Do your kids love science experiments? Mine do! We have a bookshelf of ‘making’ books, a couple of which are dedicated to science experiments. While science experiments are a huge hit with kids, parents often don’t want to do them because of the mess and because you have to buy weird ingredients that then take up half a cupboard in the kitchen or laundry. Rest assured, our ten science experiments for kids, below, require very ordinary household items and are not very messy at all. The ‘in-a-jar’ activities are particularly good for no-mess! At the end, we have listed some websites that we used to check our ingredients and that have good pictorial guides of what to do and not to do.
Make a rainbow
My kids are always fixated by little ‘rainbows’ that appear on a wall at home when the sunlight hits the right bit of glass. So, here’s how you can explain it. Get a glass of water, a piece of white paper and go to a sunny room – somewhere near a sunny window is good. Hold the glass of water above the paper so the sunlight passes through the water and creates a ‘rainbow’ on the paper. I had to move the glass around a bit, to get the right angle. This can also give you different shape/sizes to your rainbow.
How to explain it to the kids: rainbows are created when light refracts (bends) as it passes through water – just like the light passing through rain and clouds in the sky. This process separates the light into the different colours: red, organise, yellow, green, blue, indigo, violet.
Make a crystal snowflake
This one takes a bit of explaining, but it’s not tricky. Gather together:
- a jar with a wide mouth
- a pipe cleaner (white or blue is good for the ‘snowflake’ effect)
- half cup or so of borax (I found this with cleaning stuff at the supermarket – it just took a bit of looking)
- pencil or stick that sits across the top of the jar
- boiling water.
Cut a pipe cleaner into thirds and twist them together at the centre, to make a snowflake ‘star’. Tie one end of the string to the pipe cleaner and the other to the stick or pencil (long enough so that when you place the stick across the top of the jar, the ‘star’ is freely suspended in your jar). Fill the jar with boiling water and add 3 tablespoons of borax for every cup of water you added. Give it a good stir, to dissolve the borax. Now suspend the ‘star’ in the jar – so it is completely covered with the water.
Leave the jar overnight. By the morning, it should be covered in crystals to look like a snowflake!
How to explain it to the kids: crystals are molecules arranged in a repeating pattern – they extend in all three dimensions. Borax dissolves more easily in boiling, than cold water because warmer water molecules move faster and are more spread apart, which gives more room for the borax crystals to dissolve. When the water cools, the opposite happens: the water molecules move closer together, so the crystals form because there isn’t as much room for the borax, and the crystals pile on top of each other.
Make a volcano
You can make this in a glass jar, or any small container. It can keep it plain, or you could get all arty and do a plaster or papier mache volcano around your chosen container. You will need baking soda (not baking powder) and vinegar. You can add some red colouring if you want the real ‘lava’ effect. The quantity you use is up to you: it depends on the size of your volcano. To give you an idea of ratio: we did 4 tablespoons of soda to 1 cup of vinegar. Just make sure you put plenty in your container, so it spills over, lava-style. You just need to combine them in the container then stand back!
How to explain it to the kids: the vinegar and soda create an acid based reaction. When they get together, a carbon dioxide gas is formed – all the bubbling is due to the gas trying to escape. It’s similar (but less dramatic) when the bubbles rise up in soft drink. (You could also research volcanoes and lava and do a whole project on them!)
Create a tornado in a jar
Fill a jar, almost to the top, with tap water. Add around 3 teaspoons of vinegar plus a couple of squirts of dishwashing detergent. I added a sprinkling of glitter, too. Screw on the lid and swish it around, whirlpool style. Watch centrifugal force work its magic!
This is probably the one my kids liked the best, because it is very tactile. Don’t worry about the mess: the cornflour cleans up really easily. So, in a bowl, we combined water, cornflour and food colouring (go easy on the food colouring, or you’ll have stained hands for days!). The ratio should be around cornflour: water – 2:1 (so, double the amount of cornflour to water). Add in your colouring and mix it up. I’d suggesting measuring out the cornflour and water, then gradually adding the water so the kids can mix it up and watch what is happening. You want it so it ‘flows’ like a liquid, until you try to grab it and pick it up with your hands. It then acts like a solid, becoming a firm ‘lump’. It’s really mesmerising.
How to explain it to the kids: talk about the difference between a solid and a liquid. When you mix it up, the cornflour particles float around. It’s thick because these particles are very close together, but they’re tricky: they can still slip past each other. If you stir it slowly, the particles have time to move past each other, so it still ‘flows’. If you try to grab it or roll it, the water quickly flows away from the cornflour and the particles don’t have time to move out of the way – they stay all packed in together and form a solid.
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 created Hawaii!
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 too 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.
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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