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!
- 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 create 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. You can keep it plain, or get all arty and do a plaster or papier maiche 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!
- Cornflour slime
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 if 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.
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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