The Experiments on this page are offerred in good faith and the expectation that the user complies with all safety requirements and uses Risk and Assessment measures wherever appropriate.
- Air pressure demonstrations
- Alchemist's Dream
- Alka Seltzer alternative, Year 8 dissolving practical
- Alka-seltzer-a fun activity
- Angry Bottles
- Bath Bombs
- Blood model
- Bouncy Balls Recipes
- Chlorine and Bromine water production
- Coke and Mentos
- Convection Currents
- Crystal growing
- Density layers/floating demonstrations
- Digestion demonstration
- DNA Extraction
- Esters experiment alternative
- Fats and oils testing (emulsion test)
- Flame tests
- Ice cream, liquid nitrogen
- Indicators-making your own
- Iodine Clock Reaction
- Lemon Battery
- Magic Bottle
- Phenolphthalein agar: size and diffusion
- Plant Tissue Culture
- Science Chemistry Show
- Science Snacks
- Senior Science- ideas for long-term projects
- Silly putty
- Slime recipes-Australian website
- Tea bag rocket
- Vitamin C content of fruit
The Experiments on this page are offerred in good faith and the expectation that the user complies with all safety requirements and uses Risk and Assessment measures wherever appropriate.
1. Place 1-2ml methylated spirits in small plastic bottle, and place in water bath of boiling water (heat water bath on hot plate as meths is flammable).
Continue heating until vapours of meths are seen. Take bottle from water bath and quickly put cap on. As it cools, the bottle is crushed. Can be done with water but meths boils at a lower temperature and so the process is quicker.
2. Place a small amount of water in a soft drink can and heat on a hot plate or with a Bunsen burner until steaming. Plunge quickly into cold water, hole side down.
3. Use an old olive oil tin. Put a small amount of water in it, and heat on a hotplate or Bunsen with the lid off. When I comes to the boil, turn off the heat, place the tin on a heat proof mat, close the lid and pour cold water over.
4. Make it really spectacular and use 44 gallon drums. Get them free from drum recyclers. Do it outside, supporting the drums on some bricks and use a gas ring burner of the type you can get in a camping store to heat the water. The drums have a small amount of water, 10 cm or so, and bring to a vigorous boil. Turn the gas off, close the lids, and hose down. Drums collapse wonderfully!
Shiny penny or 1 cent piece
Granular or powdered zinc
Tongs or forceps
6M sodium hydroxide
Beaker filled with cold water
Graduated measuring cylinder
1. Wear goggles and take CAUTION in performing this experiment.
2. Clean a penny with steel wool. Make it as shiny as possible.
3. Place 5g of powdered zinc into an evaporating dish. Add enough 6M NaOH solution to cover the zinc and fill the dish to about one third. Heat the mixture until it just starts to boil. This should take about five minutes.
4. Use tongs to place the penny in the dish. Carefully stir the mixture with the tongs and turn the penny. Continue to heat and stir gently until the penny becomes covered with zinc and turns 'silver'. This usually takes 3-4 min.
5. Use the tongs to remove the penny. Rinse the penny in cold tap water, and pat it dry.
6. Using tongs to hold the penny, place the 'silver' penny on the hot surface of the hotplate. The penny should turn 'gold' almost immediately.
7. Immerse the penny into a fresh beaker of cold water. After the penny has been cooled for over a minute, pat it dry and record your final observations.
The chemistry explained:
1. Zinc dissolves in concentrated sodium hydroxide solution to form sodium zincate. When the copper penny is placed in this solution, the zinc plates out on the surface, displacing copper. The penny thus turns 'silver'.
2. When the zinc-coated copper penny is heated on the hotplate, the zinc and copper atoms inter-diffuse to form brass at the surface, an alloy of zinc and copper which has a gold colour.
Safety: disposal of the Zinc-NaOH solution. This mixture and the waste zinc should not be disposed of in a bin.
Rinse off the liquid with several portions of water. Add the remaining zinc to a beaker containing 200mL of 1M sulfuric acid. This dissolves the zinc to give zinc sulfate and neutralises any remaining alkali.
The waste can now be washed down the drain with plenty of water.
For the year 8 dissolving prac, try using denture cleanser tablets, which are more economical than Alka Seltzer.
Changes the colour of water to blue and also froths a little bit, adding another dimension to the prac. Meths stays clear does not froth and is a much slower reaction.
Alka seltzer tablet, within useby date
35mm plastic film canister
Do not tell the students what will happen. Get students to do a rehearsal with the film canister, but no tablet or water. All together, pretend to put the tablet in the canister, half fill with water, put upside down on the bench.
Then do it all in unison, and watch the canisters fly sky-wards. Get them to wipe up.
8g potassium hydroxide dissolved in 300mL water.
Add 10g glucose.
For blue to clear:
When dissolved, add 2 to3 squirts methylene blue.
For blue to pink:
Also add 2 to 3 squirts phenolphthalein.
For blue to yellow/green:
Also add lots of fluorescein.
Pour into a 1 litre volumetric flask or a jar and shake.
If the reaction starts to slow, take the top off to allow more oxygen in.
4 tablespoons (35 g) Bicarbonate Soda
1 tablespoon (8g) Citric Acid
2 teaspoons Sweet Almond oil
2 drops food colouring
2 drops Essential oil
•Sieve bicarbonate soda and citric acid together into a plastic cup
•Add 2 teaspoon of sweet almond oil, 2 drops of food colouring, 2 drops essential oil
•Mix all ingredients well, with pop stick
•Give a light spray with water and mix well
•Press into mould
•Package and label
500g glace cherries cut in half.
1 litre bottle of water
uncooked rice grains
4 or 5 flat oval yellow and white lollies or similar.
Teacher concocts the model while giving a lesson on the components of blood.
Cherries are red blood cells.
Water: plasma (asks How many 1 litre bottles of blood do we have in our bodies? We actually have an average of 5 litres of blood, or about 8 percent of our body weight).
Rice grains are platelets.
Lollies represent white blood cells.
Products from all 3 recipes don’t last very long, so store the balls in a small zip-lock bag between uses.
Recipe 1 (our favourite):
3 teaspoons water glass (sodium silicate). The cheapest place to buy is from pottery supply warehouses
1 teaspoon alcohol. Use alcohol based hand sanitiser as it smells less but isopropyl alcohol works too
2 drops food dye
Mix together with a spoon or pop stick until it forms a ball then squeeze out as much mixture as possible with paper towels.
If it crumbles add a little more alcohol and press it back together.
1/2 teaspoon borax
2 tablespoons warm water
1 tablespoon cornflour
food colouring (optional)
1 tablespoon liquid glue such as Elmer's
In one bowl, mix the 1/2 teaspoon borax, 2 tablespoons warm water, 1 tablespoon cornflour and a few drops of food colouring if desired. In the other bowl put the 1 tablespoon glue.
Add the borax mixture to the glue in the other bowl. Set the timer for 15 seconds. Let it set for the full 15 seconds before mixing things together.
Stir the mixture until the ingredients are combined and then start rolling the mixture in your hands until it forms a ball. It takes a while for it to dry completely
These: http://www.profbunsen.com.au/shop/item/diy-bouncing-ball-kit are just made of PVA powder.
Colour half a beaker of water with food dye. Place a pile of PVA powder into a square of Chux-cloth, roll it up into a ball shape and dunk it into the water for about a minute. Remove it, roll it into shape and let it dry a little.
Combine equal parts of polyvinyl alcohol powder and gelatine.
Try 3 teaspoons of each, varying the amount to suit the size needed. Add just enough warm water to wet the powder, add a drop of food colouring and roll in your hands to make round. Leave to dry-it only takes two minutes.
PVA supplier: ChemSupply
Both of the following procedures MUST BE CARRIED OUT IN A FUME HOOD
Measure out 40ml of household bleach (do not use the expensive variety of bleach that has been thickened)
Add 40mL of 1M sulfuric acid and then dilute with water to 100mL
Take the prepared chlorine water and add potassium bromide crystals until you get a deep brown coloured solution.
To neutralise the bromine water add sodium thiosulphate crystals until the solution is colourless.
Use Home Brand diet cola, warmed, and original Mentos that have been kept in the fridge overnight.
Professor Bunsen also offer a great delivery system available for purchase but you can make your own.
There are some good ideas for demonstration, on these websites:
This is the link to the ABC's Surfing Scientist, great demos, etc with easy set ups. Good ideas for end of year pracs.
Salt (sodium chloride or table salt) produces big crystals and you can colour them to make them easier to see.
Try phenyl salicylate also known as Salol. This solid melts at 41 to 43 degrees C so if some is placed in a test tube and then placed in hot water it becomes a liquid. Students can then drip some onto a slide and the crystals form almost instantly. It is available from Crown Scientific and Perth Scientific Equipment.
Also try ammonium chloride, magnesium sulfate and sodium thiosulphate.
FAST AND SLOW COOLING
Conical flask 150 ml
25gm copper sulfate
Few drops of concentrated sulfuric acid
1.Supply 2 flasks containing 25 grams of copper sulphate and 50 mL of water.
2. Heat and dissolve the copper sulphate, forming a saturated solution.
3. Cool one flask quickly by placing in a bucket of ice.
4. Cool the other slowly by wrapping the flask in cotton wool, then alfoil.
5. Leave both flasks overnight.
6. Examine the crystal formations.
DEMONSTRATIONS OF CRYSTAL FORMATION
The formation of crystals can be demonstrated on an overhead projector or with a video-flex.
Copper sulfate, potassium nitrate and alum (aluminium potassium sulfate) produce the best crystals.
Glass petri dish
Hot plate or Bunsen burner
Jar of the solid chemical
Boil 50 mls of the saturated solution.(For saturated solutions,look up solubility table. At 20 degrees Celsius: copper sulfate 20.5 gm per 100ml water; potassium nitrate 31.6gm per 100ml Alum 6.3 g per 100ml)
Add more solid until no more dissolves.
While still hot, pour a thin layer into a petri dish.
View on an OHP or through a video flex.
Crystals start to form within 10 minutes. If left overnight, the whole dish is covered in the familiar shaped crystals.
In test tube, does not form immediately. Overnight, structures of tall crystals form.
On petri dish, crystals start to form after 5 minutes. Particularly spectacular if left overnight.
Alum which is Aluminium potassium sulfate:
Petri dish- forms small crystals within a few minutes. These grow fairly rapidly into beautiful shapes.
Test tube-not very interesting.
Produces the best crystals in a test tube, the crystals falling out of solution as you watch.
Crystals are not very interesting, with a fuzzy mass forming in the petri dish.
If you want to investigate other ideas, type in crystal growing or crystal recipes in a web search.
1. Gas jar with layers set up as follows:
Pink tinted meths as the top layer
Green coloured water
Honey at the base
Then, gently drop in a marble which will sink to the bottom.
Followed by a 10c coin which sits on top of the honey.
Then a piece of Perspex (cut up biro tube) which sits on top of the water.
Then a piece of flat plastic which sits on top of the paraffin oil.
Finally a polystyrene ball which floats on top of the meths.
2.Set up a jar with marble-glycerol (or golden syrup)-perspex (acrylic)-water-candle wax-paraffin (or olive oil)-small dob of petroleum jelly-methylated spirits-wood.
3. Use a strong copper sulfate solution eg saturated, with kerosene on the top and 3 ping-pong balls. Two of the ping-pong balls have been filled with a certain amount of lead shot. So, one ball will sink to the bottom, one will float in between the copper sulfate & kero and the unweighted ping-pong will sit on top of the kero.
Firstly with the ping-pongs, the empty one should weigh ~2.13g and will float on top of the kero. The other two I filled with very small lead shot (2mm diameter) by drilling a very small hole in each and filling one to a total weight (ball plus shot) of 32.49g and the other 24.42g. Seal with Araldite.
If the hole is larger, it is difficult to seal. If too large, place a small square of paper over the hole, then seal with Araldite.
Before sealing, you might want to test the weights first by sealing temporarily with blu-tack and dropping them in the liquids.
You may have to change the weights a little to suit.
In a 1000mL measuring cylinder pour in approximately 370 mL of copper sulfate solution (Relative Density approximately 1.10) and gently pour in the kerosene. Drop in the heavy one first...then the second heaviest.....and so on....(there is not enough room in the measuring cylinder to drop them in reverse). Label them 1, 2 and 3.
An interesting and memorable way of demonstrating digestion for Year 11 Human Biology.
Tuna sandwich made from one piece of bread and spread.
Length plastic tubing about 3.5cm x 20cm for the oesophagus
Medium plastic bag for the stomach.
Tubing about 7 to 10 cm in diameter, fashioned from a plastic bag, cut and taped together, 60 to 70 cm long to represent the small intestine.
Lengths of poppit beads to represent the fats, proteins, carbohydrates etc.
Water: represents the various enzymes.
Green liquid detergent-bile.
Chopping board or plate.
Disposable gloves to prevent smelly hands.
Teacher explains the process of digestion from mechanical and chemical processes in the mouth through to the entry into the small intestine. Explain how the components of food are broken down by enzymes into smaller chains, as shown with the poppit beads
Chop up the sandwich on the board/plate, with the knife. What food groups does the sandwich contain?
Add a small amount of water (saliva).
Push bolus through the oesophagus into the stomach (plastic bag). Squish it together to represent the action of the stomach. Add water (acid, enzymes etc)
Transfer it into the plastic bag tubing (small intestine).
Add a squirt of green detergent (bile).
Wheat germ, kiwi fruit and onion DNA extractions all work well. The wheat germ method is simple, you get lots of DNA, and it isn't smelly.
Test the detergent, as only some brands promote the production of DNA.
There are two web sites recommended for DNA extraction pracs:
1. http://gslc.genetics.utah.edu/units/activities/ This site has an excellent wheat germ DNA extraction which I have used before. It is easy and you get lots of DNA.
All the ingredients can be bought at the supermarket. You can use rubbing alcohol instead of ethanol and it still works fine. The detail is good and easy to follow and there are a number of different DNA extractions you can try.
EXTRACTION OF DNA FROM WHEAT GERM
From Jan McGaw, Ferny Grove State High School, Queensland
Raw wheat germ
Detergent (Dawn Lemon Zest works well)
Glass hook, paper clip or pop stick
50 or 100ml beaker
2x 50 ml measuring cylinder
1. Place 1g or 1 level teaspoon raw wheat germ in a 50 or 100ml beaker
2. Add 20 ml of hot (50-60 degrees C) tap water and mix constantly for 3 minutes.
3. Add 1 ml of detergent and mix gently every minute for 5 minutes. Avoid creating foam.
4. Remove any foam with a pipette or paper towel.
5. Tilt the beaker and SLOWLY pour 14ml of methylated spirits down the side so that it forms a layer on top of the mixture. Do not mix the 2 layers together. DNA forms at the water-meths boundary. It is crucial to pour the meths very slowly so that the DNA forms in a layer on top of the water. If the meths mixes with the water, it will become too dilute and the DNA will not precipitate.
6. Let it sit for a few minutes. White, stringy DNA will begin to appear. After a while the DNA will float upwards. Use a glass hook, paper clip or pop stick to collect the DNA.
7. If you want to keep the DNA, store it in 50-70% ethanol in a sealed tube, or air dry it on a paper towel.
KIWI FRUIT METHOD 1:
Small ziplock plastic bag (15 x 9 cm)
Extraction solution (50ml shampoo, 7.5g salt and water to final volume 500mL.) enough for 25 students and don't use baby shampoo or one that contains conditioners. Try Pear's shampoo.
Small test tubes
Cheesecloth or gauze or Chux
Iced water bath
95% ethanol or isopropanol (rubbing alcohol)
Cutting board & knife
1. Cut half of one kiwi fruit into six pieces and place in ziplock bag
2. Add 20mL of extraction solution
3. Close bag, carefully removing as much air as possible
4. Press kiwi fruit and extraction solution together for five minutes
5. Using iced water bath, alternate cooling the mixture for one minute and continue to press the contents together for one minute. Repeat three times
6. Use the cheesecloth/gauze/Chux in a funnel to filter the mixture (all groups can filter through the one funnel)
7. Each person gets about 2mL of cold ethanol. DO NOT shake the tube.
8. DNA strands should form at the top of the tube and can be removed using glass rod or paper clip
KIWI FRUIT METHOD 2
Plastic Petri Dishes
¼ very ripe Kiwi Fruit
Filter paper (with a fast filter speed such as a Whatmans no. 4)
Large test tube
Test tube rack
Ice cold methylated Spirits
Pipette or dropper
25 ml measuring cylinder
25 ml of salt and detergent solution:
salt: 3g/100ml water
and washing-up detergent:10ml /100ml water
(This is best made up as a bulk solution for each group to collect 25 ml).
1.Using the plastic knives chop up the kiwi fruit into small pieces and place in 100 ml beaker with 25 ml of the salt and detergent solution.
2.Sit in a water bath for 15 minutes at 60 degrees Celsius.
3.Pour contents into a filter paper in the filter funnel.
4.Collect the filtrate in a large test tube.
5.Discard the filter paper and kiwi fruit pulp.
6.Carefully drizzle the ice-cold methylated spirits down the side of the test tube so that it forms a purple layer on top of the green layer. Let the test tube sit in the test tube rack.
7.You should almost immediately see a white layer beginning to form at the boundary between the green and purple layer. This is the DNA.
8.Use a wire loop to hook out some of the DNA.
EXTRACTION OF DNA FROM ONION
Chux cloth or similar
Protease enzyme or meat tenderiser powder from supermarket
Collect only when needed: ice, 5ml cold ethanol, disposable pipette, glass hook.
1. Chop onion into really small pieces.
2. Add chopped onion to blender with 100ml hot tap water
3. Blend for 10-15 seconds.
4. Put the blended onion into a 250ml beaker.
Add 1 teaspoon Lux flakes and 2g sodium chloride and stir well.
How does blending help to extract the DNA?
5. Boil for 5 minutes, stirring gently.
While the mixture boils, read the following:
The Lux flakes cause the cell membrane to break down and emulsify the lipids and proteins of the cell by disrupting the polar interactions that hold the cell membrane together. The soap flakes form complexes with these lipids and proteins, causing them to precipitate out of solution. Sodium chloride enables the nucleic acids to precipitate out of an alcohol solution because it shields the negative phosphate end of DNA, causing them to come close together and coalesce.
The heat treatment softens the phospholipids in the cell membrane and denatures the DNA-ase enzymes, which, if present, would cut the DNA into small fragments so that it would not spool.
6. Cool the onion mixture to 40 degrees C by stirring gently and running cold tap water over the outside of the beaker for 2 minutes and then placing it in an ice water bath, using the 400ml beaker until 40 degrees is reached.
7. Add 1 level teaspoon of protease enzyme (meat tenderiser) powder and stir gently for 5 minutes.
8. Filter through layers of Chux cloth into a 100ml baker.
9. Put 10ml of the filtrate into a 100ml beaker.
10. Add 10ml of icy cold ethanol to the beaker, pouring it SLOWLY and carefully down the side of the beaker so that the ethanol sits on top of the filtrate. You may find it easier to add the ethanol using a pipette.
11. Let it sit for 2-3 minutes. You should see the DNA precipitate out of solution near the boundary between the onion filtrate and the ethanol. It looks like mucous.
12. Gently swirl the DNA using the glass hook. Swirl so that the hook is in the onion filtrate below the ethanol and gently lift it up through the ethanol. You may have to repeat this several times to accumulate enough DNA.
Congratulations, you are one of the few people to have extracted DNA from the cells of a living organism.
Place yellow sticky traps from a hardware store in different areas of a garden. The following results came from one set-up:
The trap near the non-native ornamental plants were full of white fly, the trap near the worm farm mainly had vinegar flies and the two fruit tree traps had lots of fruit flies because there was also an attractant near the sticky trap.
Students were able to use fine forceps to pull off the insects and look at them under a microscope.
Although it was only the insect population in the one garden, they could see the biodiversity (as all the traps had common insects like small moths) and how and why there were different populations in different areas.
They then discussed the predation and also why the sticky traps were used.
Donna Jensen, Murdoch College
Can you please tell me the details of the experiment where you use jelly beans in lieu of esters?
Esters - A Tasty Investigation
This compliments Experiment 69 in the Science Teachers Association Western Australia (STAWA) Chemistry Laboratory Manual.
Key Ideas:Alcohols and carboxylic acids react to form esters.
Esters have pleasant odours and are used to give food flavour.
The laboratory preparation of esters is dangerous and not always very successful.
By giving the students the equations to write and then the jellybean to identify the flavour, the activity is enjoyable, relevant and fulfills the purpose of the experiment.
The jellybeans used are Jelly Belly brand. For suppliers, see the Suppliers page under Jelly Belly Jelly Beans. Different flavours can be bought individually by weight.
pentanol + ethanoic acid produces pentyl ethanoate + H2O (Banana)
octanol + ethanoic acid produces octyl ethanoate + H2O (Orange)
pentanol + pentanoic acid produces pentyl pentanoate + H2O (Apple)
pentanol + butanoic acid produces pentyl butanoate + H2O (Pear)
ethanol + methanoic acid produces ethyl methanoate + H2O (Raspberry)
methanol + butanoic acid produces methyl butanoate + H2O (Pineapple)
Add ethanol to a very small amount of the substance to be tested. Shake or crush to dissolve. In tough cases it can be warmed gently in a water bath.
Filter or dilute if necessary to obtain a fairly clear liquid, which is the solution of fat in ethanol.
Pour this solution into a test tube containing tap-water. A white (milk-like) emulsion indicates the presence of fats or oils.
Gentian Violet for fingerprinting is a banned substance now and is not procurable any more. Are there any alternatives?
1. On wood in silver nitrate.
2. Finger prints on filter paper in iodine chamber.
Use a fume hood.
Put fingerprints on filter paper and attach a paper clip and cotton thread to it, and dangle it into a jar containing a few crystals of iodine (also hazardous). The fingerprints slowly appear. The iodine can go back into the iodine jar.
3. On smooth non-porous surfaces with Supaglue.
(a) Put fingerprints on a suitable item. CAREFULLY squirt some Supaglue into a large zip-lock bag and place the finger-printed item into the bag. Zip it up.
(b) Put microscope slide into a glass petri dish and put a dob of Supaglue onto a cover slip or second slide beside it. The effect can be speeded up by placing petri dish lid on, because the concentration of fumes is stronger, and adding boiling water to slides (not petri dishes) because Supaglue degrades at 86 degrees C.
(c) Make a small container from aluminium foil and put a small amount of Supaglue in it. Place into a takeaway container with a microscope slide with fingerprint. Put the lid on and leave it till next lesson. The vapour from the Supaglue highlights the print.
(d) Put aluminium can which has been finger printed into a zip-lock bag. Add a warm wet cotton wool ball. WITH CARE, add generous amount of Supaglue. Blow moist hot air into bag and seal it. Float bag in large beaker of warm water.
Vapours from Supaglue attach to finger prints and crystallize out
Our text-book says to burn 2M solutions for flame tests, and I have tried solids too, but IT DOES NOT WORK! Can you please tell me what you do, and what actually works?
Buy flame test bottles (atomisers) from Haines Educational.
Use the following:
All 0.5 M. Copper sulfate, sodium chloride, potassium chloride, strontium chloride and calcium nitrate, though other soluble salts with the same cations will do.
The best results come from spraying the mist into the Bunsen burner flame from about 20 cm away, and positioning the bottle just below the top of the Bunsen burner, so that the mist goes up into the flame. The most common problem comes from the atomiser being too close to the flame when the mist is sprayed, which blows the flame out.
POP STICK METHOD: Soak pop sticks over-night in about 150mls of 2M solution and then either pull them out the next morning to dry out a bit or just give them to the students wet. Place sticks in a Bunsen flame.
Another method is to burn a small amount of the different salts on a DEFLAGRATING SPOON but this can sometimes spit so is really only suitable for a teacher demo.
Here is an experiment for demonstrating radioactive decay and half-life.
1.Get a packet of M&Ms (they only have an M on one side)
2.Count the M&Ms.
3.Place them in a beaker, shake and pour out onto a plate.
4.Remove the M&Ms that land face-up. These have decayed and need to be eaten immediately.
5.Count the remaining number of M&Ms.
6.Repeat steps 3 to 5 until finished.
7.Plot a graph of the remaining M&Ms and marvel at the shape of the best decay curve you have ever seen.
Beats Uranyl Nitrate!
THIS EXPERIMENT MUST BE CARRIED OUT IN HYGIENIC CONDITIONS IN THE HOME ECONOMICS DEPARTMENT (APPLIED CONSUMER SCIENCE DEPARTMENT).
USE FRESH INGREDIENTS FROM THE SUPERMARKET, NOT MATERIAL THAT HAS BEEN STORED IN CHEMICAL CUPBOARDS.
USE APPROPRIATE PERSONAL PROTECTIVE EQUIPMENT WHEN USING LIQUID NITROGEN
1. You don’t need a strictly measured recipe but here’s a guideline:
Pour 600mL of cream and the same amount of milk into a large metal mixing bowl.
Add castor sugar to taste (probably quite a large amount, 1-2 cups?) and stir with a wooden spoon to dissolve as much as possible.
Add a splash of vanilla essence (or some recipes use chocolate/strawberry topping to taste).
Pour in some liquid nitrogen – we used a few hundred mL over two or three pours, using a stainless steel thermos filled from our Dewar – and stir vigorously straight away. Don’t add it all at once or parts of it will freeze too hard.
Once made it can melt quickly so eat fast!
2. Generally, we use the cheat’s method because it’s much cheaper and easier.
2L vanilla ice cream (Buy the vanilla ice cream, let it melt and transfer to large metal bowl.)
1 cup Smarties
250ml Choc sauce
Large flat wooden spoon
1L liquid nitrogen
Mix choc sauce into ice cream.
Slowly add liquid nitrogen whilst stirring with wooden spoon adding the smarties as it begins to thicken.
Continue adding liquid nitrogen until completely frozen.
Spoon into small cups.
(Making up an ice cream recipe using cream, etc would just require following the recipe, until it is ready for freezer, then using the liquid nitrogen instead.)
If there is a little nitrogen left over, staff can have a treat with a sorbet. –melt 1 cup sugar in 1 cup water in microwave. Mash up a punnet of strawberries or other fruit. Mix, then and add liquid nitrogen.
3. Buy some tubs of cream (approx 2 tubs for about 20 people for a spoon size taste each) put them in a stainless steel bowl. Add flavouring if desired, we use strawberry, pour in liquid nitrogen and start whisking taking all safety precautions such as goggles, mitts, etc. It doesn't happen instantly but takes at least 10 minutes and the resultant ice cream tastes different and doesn't have the same texture as the commercial product, however the kids love making it.
4. Allow 2 litres per class to fully melt (takes a few hours).
Then pour in the liquid nitrogen while stirring icecream. Kids will love it!
5. Buy a tub of ice cream and allow it to melt, or:
Prepare the night before:
3 eggs lightly beaten
50g caster sugar
Evaporated milk 410ml
Heat milk, chocolate, eggs and sugar in double saucepan, stirring constantly until mixture coats the back of a spoon.
Just before adding nitrogen:
Whisk evaporated milk and add. Whip cream and add.
Mix in nitrogen as quickly as possible while the mixture is still well aerated.
Note: the volume of liquid nitrogen is approximately the same as the volume of the ice cream mixture (1 litre)
Re the experiment in Lower Secondary Science, Can you make an Indicator?:
Red cabbage, red roses, onion skin and black tea work but flowers from your schools garden make great indicators.
The following flowers work very well:
Pink Camellia, flame tree, Grevillea Robyn Gordon, sour grass, nasturtium- orange flower form, white (with purple back) daisy, red (and pink) pelargonium, Polygala, pink and red roses.
Simply grind a small amount in water with a mortar and pestle, filter if you wish and test with acids and bases.
Those which don't work are lavender and dandelion.
This demo shows a chemical reaction which can be used to show how concentration affects reaction rates.
Students will observe and describe chemical and physical change.
Differentiate between common chemical and physical changes.
Analyse factors that influence chemical and physical change.
INTENDED LEARNING OUTCOMES
1. Make observations and measurements
2. Collect and record data using procedures designed to minimise error.
3. Analyse data and draw warranted inferences.
400 mL. distilled Water
1.6 gm of KIO3
320 mL. distilled Water
1.6 gm powdered starch: add a little water and make into paste
1 gm Na2S2O5-Sodium Metabisulfite
2 mL. concentrated sulfuric Acid
Add starch to 320 ml boiling water, boil for 2 more minutes. When solution is cool to touch, add Sodium metabisulfite and sulfuric acid. Add an additional 500 mL. of distilled water to the solution.
1. Pour 50 mL of Chemical A into a 250 ml flask.
2. Pour 50 mL of Chemical B into the same flask.
3. Time how long it takes for the reaction to be completed, mark it on a graph on the board.
4. Mix 40 mL of chemical A with 10 mL of distilled water and 50 mL of chemical B, time the reaction and mark it on a graph on the board.
5. Mix 30 mL of chemical A with 20 mL of distilled water and 50 mL of chemical B, time the reaction and mark it on a graph on the board.
6. Mix 20 mL of chemical A with 30 mL of distilled water and 50 mL of chemical B, time the reaction and mark it on a graph on the board.
7. Mix 10 mL of chemical A with 40 mL of distilled water and 50 mL of chemical B, time the reaction and mark it on a graph on the board.
Teachers and students: be sure to keep all Chemical and Fire Safety Rules that are specified by your teacher and in all general laboratory experiences. Wear an apron to keep the chemicals off your clothing.
1. What happened to the reaction rate as you diluted solution A?
2. Why do you think the reaction change speed?
3. Predict what would happen if we increased the concentration of solution A? Defend your answer.
NOTES AND VARIATIONS:
This comes from the teachers’ guide of the old Chemistry Experimental Foundations course. Works every time and always has the “wow” factor!
An interesting variation on this, used with good success in lower school and even upper primary students as extension is to heat the test tubes with solutions A and B in the microwave for the temperature experiment before adding them together.
Trying to use a beaker of warm or hot water to heat the two test tubes is slow and messy.
You can get a great set of results by heating the test tubes (standing in a 250mL beaker) in the microwave for 3, 6, 9, 12, 15 seconds etc and it is quick and the results are good.
Note the upper limit on useful temperature is about 60 degrees C.
This comes from Queensland Science 2, Working Scientifically, Detecting Ions, Experiment 1.5. The method is an alternative to the one in the book, which does not work:
Bathroom tile (eg 15x15cm) covered with aluminium foil
Connecting leads and crocodile clips
0.5M potassium iodide
0.5M sodium thiosulfate
Soak the filter paper in a mixture of 10ml potassium iodide, 5ml sodium thiosulfate, 5 drops starch solution, 3 drops phenolphthalein.
Connect 6V power pack, -ve to foil, +ve to filter paper. Draw on the filter paper with the nail.
Does anyone have any tips on how to make the lemon battery work?
We are using Jacaranda Science Book 2, page 231.
For best results with a lemon battery use BROAD pieces of zinc and copper (1-2cm wide, roughly polished with sandpaper). Use a high impedance meter (any digital multimeter) to monitor the voltage produced (it will be around 0.9 volts per battery). [Do not use a school quality analogue meter (those with a needle) because they draw too much current, which causes the voltage produced across the zinc and copper electrodes to drop right off].
YOU CANNOT MAKE A GLOBE GLOW, because of this same problem. You can however use a Light Emitting Diode (LED) instead; because they draw much less current (these are readily available at Dick Smith). But it must be connected the right way around or it will not work (just reverse the connection).
AT LEAST THREE, THOUGH PREFERABLY 4 OR 5, LEMON BATTERIES IN SERIES** WITH EACH OTHER IS REQUIRED TO LIGHT THE LED. Get the students to link them together if not enough sets to go around. Shroud the LED to see the glow more clearly.
** To connect in series, means to connect the zinc electrode of one battery to the copper one of another, and so forth. Connecting like electrode to like electrode (i.e. a parallel connection) will increase the current, BUT NOT the voltage - A THRESHOLD VOLTAGE OF 1.7 VOLTS is required to activate an LED# #.
SOME ADDITIONAL (& RELEVANT) INFO:
A lemon battery can produce 0.9volts, but minuscule current, because of the lemon battery's high internal resistance.
Good old Ohms Law comes into play, ie Volts=Current x Resistance, or more appropriately expressed here, Current = Volts/Resistance.
From this equation you can see that a high resistance will give a very low current.
# # THRESHOLD VOLTAGE OF 1.7 VOLTS: Since 1.7 volts is required, one needs to put at least three, but preferably 4 or 5 Lemon Batteries in series with each other to get the required voltage. [Just two is not sufficient, because, as explained above, whilst each battery produces 0.9 volts, the voltage will drop off significantly when connected to the load (the LED in this case). This effect can be observed by simply connecting a digital multimeter (on DC Volts setting) across the battery's electrodes, and noting how the voltage goes down when the LED is connected. This is the case with ANY type of battery, though significantly more pronounced with a lemon battery.]
COCA COLA BATTERY:
Set up 3 Coca Cola cells in series using copper and zinc electrodes. It will light an LED eg 5 Amp, available from Altronics, Perth. Connect the LED the correct way around.
By Ian Sullivan, Noble Park High School.
A stimulating demo, good introduction to the topic Introduction to Chemistry.
Bottle contains 500ml of fresh 1M H2SO4 with 0.5g of anhydrous iron(III) chloride FeCl3. Solution in the bottle is nearly colourless.
Use a wine bottle and appropriate glasses rather than a flask and beakers.
Practise, with a view to adjusting quantities of chemicals in the glasses, which should not be visible to an audience.]
Scientific explanation should not come until the trick is completed. The array of beverages appears to flow from the same bottle of sulfuric acid plus iron chloride.
Set up glasses containing solutions as follows. Pour solution of sulfuric acid into each consecutive glass.
1.PORT 1 ml fresh saturated ammonium thiocyanate soln NH4SCN
2.SHERRY 2ml saturated iron(III)chloride solution FeCl3.
3.WINE/CLARET 1 drop fresh saturated ammonium thiocyanate soln NH4SCN
4.MILK TUMBLER 2 ml. lead nitrate 0.1M
6.CHAMPAGNE 1g sodium hydrogen carbonate (sodium bicarbonate)
7.COLA/SOFT DRINK 1g sodium hydrogen carbonate (sodium bicarbonate) and 1 ml saturated ammonium thiocyanate.
8.INK OR CURACAO LIQUOR 1ml saturated potassium ferrocyanide K4Fe (CN)6.3 H2O
The original prac is in Biological Science, The Web of Life Teacher’s Guide Part 2, Exercise 10b.4
1. Approx 25g agar (increase from 18g)
Dissolve NaOH in 100ml water.
Heat 900ml water in a beaker almost to boiling
Add agar and continue boiling while stirring till dissolved. Allow to cool until temperature drops below 60C then add NaOH, still stirring.
Add phenolphthalein until very deep pink – 6 droppers full.
Allow to set then cut unto 1cm, 2cm and 3cm cubes, leaving some for cylinders.
Do NOT refrigerate (it fades). Can be made 2-3 days in advance if you take it out of container and leave loosely covered with plastic wrap on glass Petri dish and store in chemical store shelf.
2. Calculate amount of agar required to make gel at 1 cm, 2 cm & 3 cm deep
Dissolve 18 g agar per litre in distilled water. Microwave in 1L beakers, with caution
Add 4 g NaOH per litre after agar solution has cooled below 60C then add – phenolphthalein and pour into containers. Can last for 2 weeks in the fridge
3. We provided kits for students:-
Kit set up in large plastic tray containing – 500 ml 0.1M Sulphuric Acid
2 pairs gloves
large crystallizing dishes. These make removing the agar blocks easier than using beakers which are much deeper.
small white plastic dish for cubes of phenolphthalein agar -1 cm3, 2 cm3 & 3 cm3
To make up 500mL of jelly for the cubes, weigh out 9g of agar and 2g solid NaOH. Dissolve the NaOH in 50mL of water. Heat 400mL of water in a beaker almost to boiling, add the agar and stir until dissolved. Allow to cool then, when the temperature falls below 60C, add the NaOH solution, stirring continuously, until the jelly is deep pink. Allow to set. The agar can then be cut into blocks of the appropriate sizes.
4. 36gm agar
1600ml water, enough for 24 groups with 1 x 3cm,1 x2 cm,1 x 1cm block each
9gm NaOH in 100mls water
Phenolphthalein in dropper bottles
Make agar with water & boil till dissolved until clear solution
Dissolve NaOH in the water stirring constantly as this is exothermic
Cool agar to 60 deg C then add NaOH soln - this is important
Add phenolphthalein - a lot at first then drop by drop till agar is a deep pink colour
Pour into containers to set. You can use the rectangular “Unitray” which has square corners.
5. 1800mL boiling water + 40g Agar, stir until dissolved
Turn hot plate off, but leave stirrer on and wait until it drops to less than 60oC.
Mix 6g NaOH in 150mL water and add to above
Squirt in 200mL Phenolphthalein. Yes, 200mLs!
Pour it into plastic dropper bottle trays, the “Unitray”. Leave overnight to set and the students then cut them to sizes
6. We changed the prac because the agar tends to fade. Make the cubes ahead of time. Students place them in 0.5% potassium permanganate solution for 5 minutes then slice as per the Student Prac book. It works really well.
FROM THE CSIRO LAB AT SCITECH:
There is a program in the CSIRO Lab at Scitech called PLANTECH.
Another sterile technique of tissue culture, carried out in laminar flow cabinets, is being offered for high schools, called an embryo rescue. It is also used in conservation biotechnology at Kings Park, plus a huge range of other plant biotechnology and botanic activities.
Agar is not actually needed to do enquiries into the effect of plant hormones on growth.
Plant rooting hormones and potting mix or vermiculite can simply be used. The best way to measure roots is to harvest the plant, wash it out and use a grid that you lay the roots across and count the number of intersections of roots across the lines.
Hormones can be bought at gardening and hardware stores and probably at scientific suppliers.
Low grade agar powder is fine.
Sugar needs to be in the agar, plus a complete fertiliser and M&S (Murashige and Skoog) basal medium
Sugar encourages fungal and bacterial growth, so the vials must be sterilised in an autoclave or pressure cooker. Be aware that some types melt, some don’t.
PLANT TISSUE CULTURE:
Prepare media for agar vial tissue culture at least one day before class
Mix in 2 litre beaker:
1 bottle MS (nutrients) 4 g (rinse out)
1 litre distilled or tap water
30 g sucrose. Sucrose aids photosynthesis but also promotes microbial growth
Adjust pH to 6 with sodium hydroxide solution or HCl (10%), added drop-wise with a pipette
8 g agar
Let it boil to mix agar (in microwave), approximately 5 minutes
Pour into polycarbonate vials ready to autoclave (sterilise)
Eg: 10 ml in 120 mL vial. Smaller containers mean that can get more out of the 1 litre agar.
Prepare tools for autoclave or pressure cooker.
Livingstone Mediplast-pressure tape (autoclave masking tape with colour change)
2 forceps, 2 scalpels or dissecting scissors
Sterilise laminar flow cabinets
Wipe down regularly with ethanol
Leave UV light on for at least 20 minutes
Or do this in a sterilised aquarium. This is not as good but much cheaper.
You can propagate plants from softwood cuttings.
Auxins (plant hormones) induce new root formation.
In horticulture, auxins, especially Indole-3-butyric acid and Indole-3-acetic acid, are commonly applied to stimulate root growth when taking cuttings of plants.
In a couple of weeks, plants will have adventitious roots.
Adventitious roots differ from the more usual root formation of branches of a main primary root, and instead originate from the stem, branches, leaves, or old woody roots.
LOOKING AFTER YOUR CLONED PLANT:
The cloned plant can be transplanted within three weeks, when it has started to develop adventitious roots. It can transplanted it into a pot with potting mix.
The new plant is a clone as it has the same genetic material (DNA) as the parent plant from which it was cut.
PLANT TISSUE CLONING
What to do
1. Wash and dry a pair of scissors. Clean scissors are required to avoid infection and disease.
2. On the petri dish, cut a piece of shoot from a main stem of your parent plant making sure there is a node.
3. Remove most of the older leaves so that the plant doesn’t use too much water or die because of a lack of roots. Place unwanted plant material in the bin.
4. Keep only the young growing shoot. This called an explant.
5. Make sure that your explant is the right way up.
6. Dip the bottom end of the explant into the auxin (plant hormone).
7. Shake off any excess root hormone.
8. Remove the lid from your vial.
9. Push the explant into the agar.
10. Replace the lid.
It is important to shake off surplus auxin (plant hormone) as too much auxin will stop root growth. A small amount of root hormone will make adventitious roots grow.
BIG LITTLE SCIENCE CHEMISTRY SHOW:
Planning amounts for 3 shows, plus 3 trial runs
1. LUMINOL “LIGHT PIPE”
big stand with clamps and tubing
2 L beaker
big glass funnel
Solutions: 3–Bottle A (Dilute 4.0 g Na2CO3 to 500 mL, add 0.2 g Luminol and stir to dissolve. Add 24.0 g
NaHCO3 , 0.5 g (NH4)2CO3•H2O and 0.4 g CuSO4•5H2O and dissolve. Dilute to 1 L.)
3–Bottle B (50 mL of 3% H2O2 diluted to 1 L)
To Perform: Pour equal amounts of bottles A and B into funnel, with lights off (adjust pouring rate to get maximum glow)
What is Happening: Luminol is a special molecule which reacts to form a product having electrons in a highly excited energy level. As the molecule loses energy and its electrons fall down to a lower energy state, the energy lost is in the form of light.
2. DRAGON’S BREATH
Candle taped to the end of a meter stick
Chemicals: Make a mixture of 100 mL of ethanol, 15 mL of water and about 3 g of lithium chloride. Shake to
dissolve as much lithium chloride as possible.
Put about 50 mL of ethanol in the spray bottle. Hold a lit candle at arm’s length. Hold the spray bottle about 4–6 inches from the candle and quickly spray ethanol through the flame.
This should produce a nice little fireball that lasts for a second.
3. ELEPHANT’S TOOTHPASTE
500 mL graduated cylinder
sponges for clean up
Solutions: 300 mL of 30% hydrogen peroxide
45 mL of dish washing detergent
30 g of potassium iodide
WEAR GLOVES! Pour about 100 mL of hydrogen peroxide into the graduated cylinder, add about 15 mL of detergent and add about 10 g of sodium iodide. Huge yellow worm springs out of cylinder!
What is happening: The hydrogen peroxide oxidizes the iodide ion to iodine, while simultaneously releasing oxygen gas. The gas is trapped in the detergent, creating a foam.
4. SHAVING CREAM IN A VACUUM
bell jar with bell jar base
can of shaving cream
large Petri dish supported over three pieces of wood (to avoid plugging of air exit hole)
Put a generous daub of shaving cream in Petri dish, put bell jar over dish base, turn stopcock to off, connect vacuum pump to bell at stopcock and turn on pump. Open stopcock and watch shaving cream swell up and completely fill inside.
What is happening: The shaving cream is full of gas bubbles in equilibrium with the gas pressure of the atmosphere pushing down on the bubbles. When the air is removed, the bubbles expand.
5. DISAPPEARING WATER
Equipment: Part A:
small glass (with even lip)
6–pieces of cardboard (About 15 cm x 15 cm)
Part B: Styrofoam cup
15 cm square piece of cardboard having “Do not remove this cardboard” written on
400 mL beaker
Chemicals: jug of water, sodium polyacrylate powder
To Perform: Part A: Fill the glass 3/4 full of water, place the cardboard over the end of the glass and invert the glass. Let go of the cardboard and the water stays in the glass.
Part B: Put some sodium polyacrylate powder into a Styrofoam cup (ahead of time, unseen).
Have a student hold the cup in the air with both hands. Then pour water out of the pitcher into the cup and put the second piece of cardboard over the mouth of the cup. While the student is still holding the cup, turn it upside down over the student’s head and lower the cup onto the student’s head. Then, pull the piece of cardboard out and have the student read the card. Finally, lift the cup up off the student’s head, showing that no water comes out.
What is Happening:
As the water tries to come down out of the glass, the pressure inside the cup is lowered. The greater pressure of the atmosphere outside then pushes the cardboard firmly against the rim of the glass.
The sodium polyacrylamide quickly forms a gel when water is added.
6. MELTING STYROFOAM CUP
250 mL acetone in juice bottle, with small label
500 mL distilled water in juice bottle, with small label
4 new Styrofoam cups
Pour distilled water into cup and drink. Ask if someone else wants a “nice strong drink” and quickly pour half a cupful of acetone (HOLD IT OVER AN ORANGE BUCKET WHEN OFFERING IT TO SOMEONE – you have 3 seconds before the bottom drops out!)
7. DRY HANDS IN WET WATER
2 L beaker
jug of water
Chemicals: Lycopodium powder in a test tube
Pour test tube of Lycopodium powder onto the surface of the beaker of water. Slowly push hand below the surface of the water and then bring your hand back out. The hand will be dry.
What is Happening: Lycopodium powder is “hydrophobic” (it repels water, similar to oil). When a hand
is pushed down into the water, a thin layer of air is trapped between the hand and the powder. Since the powder repels water, the hand remains dry. The beautiful silvery colour of the water against the hand is actually the reflection of light off the water–air interface. (This might be similar to how a fish sees the sky.)
8. SMOKE CANNON
extra elastics (large and long)
Solutions: Concentrated hydrochloric acid (in squirt bottle)
Concentrated ammonia (in squirt bottle)
Place some ammonia and hydrochloric acid at different places on paper towel inside cannon.
Pull back handle and fire.
What is Happening: Ammonia and hydrochloric acid give off fumes which combine to form a “smoke” made of solid ammonium chloride. As the air rushes out of the mouth of the cannon, a region of partial vacuum forms in the region behind the onward–rushing air. This partial vacuum pulls in the surrounding air and forms a doughnut–like “vortex” which is similar to a miniature “tornado”.
9. THE METHYLENE BLUE TRAFFIC LIGHT
500 mL Florence flask with stopper to fit
Chemicals: 300 mL distilled water
8 g potassium hydroxide
10 g dextrose
6–8 drops of methylene blue indicator (indicator solution prepared by dissolving 0.20 g
methylene blue in 100 mL water)
Dissolve 8 g KOH in 300 mL distilled water in 500 mL Florence flask. Just prior to doing the demonstration, dissolve 10 g dextrose in the KOH solution and then add 6–8 drops of methylene blue solution. Swirl the flask and allow it to sit undisturbed until it becomes colourless (about one minute).
To do the demonstration, give the flask a quick shake or two. The blue colour appears again and then slowly fades. This process can be repeated many times.
What is Happening: The oxygen present in the flask oxidizes the methylene blue dye to its blue form. The basic conditions cause the dextrose to reduce the methylene blue dye to its colourless form.
Shaking the flask reintroduces more oxygen into the solution and re-oxidizes the methylene blue to its blue form, continuing the cycle until the oxygen in the flask is used up.
10. SUPERFAST ICE
6–250 mL flasks, with stoppers
2–yellow tote trays
600 mL beaker (to contain scrapings)
In a clean 250 mL flask, dissolve 130 g of sodium acetate in 100 mL distilled water (with heating). Stopper and let cool COMPLETELY UNDISTURBED. Prepare 6 such flasks.
Also have on hand a small beaker with a gram or so of sodium acetate crystals.
Carefully move the flask to where the demonstration will take place – DON’T JAR IT!
Unstopper the flask and, while holding the flask up for the audience to see, add a couple of crystals of sodium acetate.
What is Happening: Sodium acetate has a peculiar crystal structure. When this compound is melted, it is difficult for the molecules to “remember” how to form a crystal again. The solution is “supersaturated” and when a crystal of sodium acetate is added to the liquefied material, the sodium acetate suddenly “remembers” how to crystallise and BINGO!
11. NEON LIGHT AND FLUORESCENT LIGHT
Old neon sign from sign company specialising in neon signs
stands and clamps for neon lights
To perform: Touch one end of the neon light with an operating Tesla coil. A bright red light emission from neon is seen near the metal electrodes; the colour then changes depending on the coating inside the glass tube. (Argon lights give a blue emission.)
Have one person hold the fluorescent tube and another person touch the Tesla coil to the tube, lighting up the tube.
candle and matches
Chemicals: pieces of guncotton
To Perform: throw the guncotton into a flame
What is Happening: The cellulose in the cotton has been treated with nitric acid to make nitrocellulose, which burns rapidly and leaves no residue.
13. AN ORGANIC RAINBOW
500 mL separatory funnel
2–400 mL beaker (one to contain HCl and one to catch liquid from separatory funnel)
1 L beaker to hold ice for cooling HCl
distillation apparatus (optional)
magnetic stirrer, with stir bar
500 mL graduated cylinder or (600 mL beaker and 250 mL graduated cylinder)
10 mL graduated cylinder
250 mL 70% ethanol (175 mL of ethanol + 75 mL of water)
1 mL of tert–butyl chloride
4 mL of universal indicator a few millilitres of 1 M NaOH
Into either a 500 mL graduated cylinder or a 600 mL beaker place 250 mL of distilled water and 250 mL of isopropyl alcohol. Place the container on a magnetic stirrer and begin stirring. Add 1 mL of tert-butyl chloride and stir for another 15 seconds, add 4 mL of universal indicator and stir for another 15 seconds. Finally, add a few drops of 1 M NaoH and continue stirring. The initial blue colour will turn to green, orange and finally red. The process can be repeated by adding some additional NaOH to the reaction mixture.
14. DISSOLVING STYROFOAM
Magnetic stirrer, with stirring bar
2 L beaker
large bag of polystyrene packing chips
400 mL of acetone
To perform: Rapidly stir 400 mL of acetone in the 2 L beaker. As the foam chips are added, they rapidly dissolve. Students are usually amazed at the large volume of chips that can be reduced to a substantially smaller volume.
15. OSCILLATING REACTION: YELLOW AND BLUE
Magnetic stirrer, stir bar, 500 mL beaker, 3–100 mL graduated cylinders, piece of white paper to serve as a backdrop, sticky tape.
Solutions: Solution A = 120 mL 30% hydrogen peroxide added to 300 mL distilled water
Solution B = 1.29 g potassium iodate and 1.5 mL concentrated sulphuric acid added separately to
400 mL distilled water
Solution C = Make a paste of 0.15 g soluble starch in some hot water and add, with
stirring, to 500 mL water. Then add 7.8 g malonic acid and 1.7 g MnSO4•H2O.
Put 50 mL solution A in 600 mL beaker and sit on magnetic stirrer at lowest setting. Then
add 50 mL solution B and then 50 mL solution C.
16. LYCOPODIUM EXPLODER
Lycopodium exploder (see reference or below)
small birthday candle
rubber tubing: 10 mm OD, 150 cm
wide stem Beral pipette
sponge (for clean up)
Chemicals: Bottle of Lycopodium powder
Insert the tubing into the bottom of the plastic bottle. Arrange the candle so the wick is in the centre of the bottle. Use the pipette to place 3–5 “loads” of Lycopodium into the bottle end of the tubing. Make sure the end of the tubing is aimed at the end of the candle and light the candle. Turn off the room lights: take a large breath and blow into the other end of the tubing. A huge fireball erupts above the bottle.
Science Snacks are miniature versions of some of the most popular exhibits at the Exploratorium, San Francisco.
Senior Science students can grow native trees from seed, in conjunction with the Men of the Trees. They germinate them in different media and measure growth rates.
The students can set up aquaria with tropical fish and look after them. Alternatively, they set up the tanks with yabbies. The students enjoy doing this and the other classes benefit as the aquaria are in the classrooms. They do not cost too much to feed and they do not smell, unless one dies and it is not seen straight away. Keeping yabbies does not need heaps of Animal Ethics paperwork.
Other projects involve setting up a garden from scratch, composting and growing vegies from seedlings.
Marine Studies: snorkelling, boating (including knots and channel markers), archaeology, Bathymetric models and the term project of building aquaria and running fish aquaculture.
Does anyone have a recipe for sherbet which includes jelly crystals please?
I tried many recipes, and the winners are:
icing sugar 1 tablespoon
Bicarb soda (Sodium hydrogen carbonate) quarter teaspoon
citric acid quarter teaspoon
jelly crystals 1 teaspoon
Bicarb soda 1 teaspoon
icing sugar 10 teaspoons
citric acid 1 teaspoon
jelly crystals 3 to 4 teaspoons
We have been trying to make silly putty. We have some recipes but have not been very successful.
Does anyone have a tried and true recipe which will produce stretchy and/or bouncy putty?
25 ml Craft-Tec PVA glue (from Emtex Handcrafts/School Mart 9 Sevenoaks St Bentley phone 9356 2392 and 9356 2242) (other brands don't work as well).
10 ml 5 percent borax solution.
Pour 25 ml glue into 100 ml beaker. Add 3 drops food colouring and 10 ml water and stir.
Slowly pour borax solution to the mixture in portions, with continual stirring.
Rinse putty under running water whilst moulding it in your hands. Dry with paper towel.
Store in a plastic bag.
A MORE DIFFICULT REACTION (Suitable for Year 8s)
THE FOLLOWING CHEMICAL REACTION REQUIRES VERY CAREFUL AND ACCURATE HANDLING.
SOME OF THE CHEMICALS YOU WILL USE ARE POTENTIALLY HAZARDOUS!!
FOLLOW ALL INSTRUCTIONS VERY CAREFULLY!!
1.Collect safety glasses for all members of your group.
2.Collect the following:
1x 100 ml polyvinyl acetate (C5H8O2) (handle with extreme care) (PVA glue)
1x white plastic container (ice cream container)
1x 250ml beaker
2 ml chloronitrobromine (Food colouring)
Sodium borate (Na2B4O7.10H2O) Safety glasses must be worn- this is an eye irritant) Borax-2.5 g/ 50ml for a 5 percent solution
Very hot water-from kettle when required.
1x stirring rod
1.Making sure all safety precautions are in place, carefully pour the polyvinyl acetate into the empty white container.
2.Add 50 ml of tap water (use a beaker). Stir.
3.Add the chloronitrobromine. Stir until combined.
4.Let this mixture stand while you CAREFULLY place the sodium borate into the other empty beaker. Add 50 ml of very hot water, stirring with the stirring rod until completely dissolved.
5.Carefully pour this solution into the polyvinyl acetate and water mixture, stirring to combine.
Note: students should still wash hands after playing with this putty.
AT THIS POINT, ASK YOUR TEACHER FOR THE FINAL SHEET OF INSTRUCTIONSâ€¦.
NOW THAT YOU HAVE WORKED AS SENSIBLE, RESPONSIBLE CHEMISTS, ITâ€™S TIME TO PUT AWAY YOUR SAFETY GLASSES!!
WITH COMPLETELY UNPROTECTED HANDS, KNEAD AND MIX YOUR REACTION UNTIL IT RESEMBLES SOMETHING THAT YOU MAY HAVE PLAYED WITH IN YOUR YOUNGER YEARS!!
1 x 100 ml beaker
1 x 250 ml beaker
2 glass stirring rods
100 ml measuring cylinder
1 g guar gum powder
1.5 g borax powder
1 plastic teaspoon of glycerol
1. Put the guar gum in a 250 ml beaker and add 80 ml of tap water, stir with rod
2. In another beaker, dissolve the borax in 30 mls of HOT tap water
3. Add the glycerol to the guar gum solution and keep stirring. While stirring add one or two drops of food colouring
4. Slowly add the borax solution to the guar gum solution, stirring it constantly. Stop adding when the slime reaches a desired consistency
Exciting and new demonstrations in science. All tried, tested and guaranteed to work. Also, science humour including Rules for Teachers from 1872.
Use tag-bag teabags, the ones with the string and tag.
These are actually tissue cylinders.
Carefully remove the staple and the string and empty the tea out.
Open the cylinder, but do not open out the fold.
Place open side down on a bench.
Light the folded part at the top, and observe.
You can also stand it on your hand, and this is where your trust in the laws of physics is tested !
Does anyone have information on how to test the Vitamin C content of different fruits?
We do a simple practical using 5 different juices: freshly squeezed orange juice, bottled 100 percent cordial, lemon juice and boiled orange juice as comparisons. You could also use grapefruit but note that if you were using, for example, strawberry then you would not be able to see the colour change of the DIP solution easily.
Make up a 0.1 percent solution of DIP (2,6-DICHLOROINDOPHENOL SODIUM SALT), which can be obtained from Southern Biological Services Pty Ltd. It is expensive and comes in very small quantities. It must be a fresh solution.
In the prac:
(1) Add 20 drops of DIP to a clean, dry test tube.
(2) Add the juice to be tested to the DIP. ONE DROP AT A TIME and gently shake the tube to mix the contents after each drop. Count the number of drops of juice it takes to turn the DIP colourless.