Do your kids love science experiments? Mine do! With National Science Week upon us (12-20 August), we are revisiting our favourite science experiments to do with our kids. Don’t worry: they don’t’ involve weird, hard-to-find equipment or ingredients! Many are actually in jars, as well, so not to bad on the mess front!
- A cloud in a jar
Get a clean jar and swish a few centimetres of boiling water inside it (this bit is for the grown ups to do). You want to warm up the sides of the jar by doing this. Take the lid and turn it upside down. Put a few ice cubes in it (so it’s like a little plate of ice cubes). Place it on top of the jar that has the boiling water in it, so it’s just resting on top of the jar. Leave it there for a couple of minutes. Then get an aerosol can (something like hairspray) and quickly take off the lid, spray a small amount of aerosol inside, then pop the lid back over the top, with the ice still on it. Now watch what happens. A ‘cloud’ will start to form inside the jar, on top of the water. Once it has clearly formed, you can remove the lid and watch it float away.
How to explain it to the kids: you created warm air, from the boiling water. It rose up to the top, then was cooled down when it hit the icy lid. When the warm air cooled, it wanted to go back to being a liquid. The aerosol created something called ‘CCN’ – cloud condensation nuclei. CCN are usually small particles that float in the atmosphere for water vapour to ‘hang’ onto, so it can form clouds. You just recreated a cloudy atmosphere in your little jar! Add an island paradise in there and you’ve create Hawaii! J
- Demonstrate a rain cloud
My son often asks about ‘how the clouds let go of rain’ and what it looks like. So, this is a very non-technical way of demonstrating it. Get a clean jar and fill half to two thirds with cold water. Gently apply shaving foam on top of the water, to create your ‘cloud’. We then added blue food colouring, drop by drop, until the foam could no longer hold it all and the colouring ‘rained’ down, into the water. Just like a cloud, that gets so full of water, it can’t hold any more and it rains.
- Make a lava lamp
You can use a jar or empty water/soft drink bottle for this. Just don’t go to big, or you’ll need heaps of oil! Fill your container around two thirds with vegetable oil, then top up with water. Add a few drops of food colouring then break in one or two alka-seltzer tablets. Put the lid on and watch what happens! You can add more alka-seltzer to make it bubble again.
How to explain it to the kids: oil and water don’t combine. The oil floats on top of the water because the water is more dense (heavier). The food colouring will pass through the oil and collect at the bottom of the water. The alka-seltzer fizzes as it creates bubbles of carbon dioxide gas. These bubbles travel up through the colour, water and oil, taking some of the coloured water with it. When the bubbles break on the surface, the coloured water falls back down again.
- Rainbow skittles
On a small plate or saucer, layout out some ‘Skittles’ in a circular pattern. Add a little warm water to the plate, so the lollies are just sitting in it. Watch as the coloured ‘shells’ on the skittles start to dissolve and create a rainbow effect. This is actually a good one to do with littlies, as you can get them to identify colours. My kids experimented with putting the lollies closer together on some plates, to see what different patterns they would make and how long it would take the bands of colours to mix together.
- Make a bouncy egg
This one will take 4-5 days. It’s pretty simple: put an egg in a cup full of vinegar. Make sure it is completely covered, then leave it. What happens? The vinegar actually dissolves the egg shell. When it has completely dissolved, you can remove the egg. You will be left with a very strange, rubbery egg.
How to explain it to the kids: the vinegar is an acid. It dissolves the calcium carbonate of the shell, leaving the membrane of the egg. This membrane is resistant to the vinegar. That means that instead of having a runny egg all through your cup, you can pick it up and it feels rubbery.
Here’s a list of very helpful websites:
Have fun with these science experiments! They’re a great introduction for questioning little minds!
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