We know, if you're going to get the food colouring out, an experiment doesn't just need to work – it needs to wow your child! We promise this roaming rainbow is worth a little bit of effort. Plus, it'll make science come to life for your child.
Rather watch than read? Hit play on the video below!
You will need:
- 7 glasses
- Red, blue and yellow food colouring
- Kitchen roll
Rainbow walking water experiment
Put water in four of the cups (fill them almost to the top). Put five teaspoons of red food colouring in the water of two cups, then do the same with the yellow and then the blue in the other two cups.
Position the cups so you alternate the empty ones with those filled with coloured water.
Take a sheet of kitchen roll and fold it lengthways, twice.
Position the kitchen roll strips in the cups. If they're a bit long, you can trim them.
Place the strips in this order:
- One in the red cup leading to the empty cup next to it.
- One in that empty cup leading to the blue cup.
- One in the blue cup leading to the empty cup next to it.
- One in that empty cup leading to the yellow cup.
- One in the yellow cup leading to the empty cup next to it.
- One in that empty cup leading to the red cup you started with.
Be amazed as the water starts to walk! In the next few minutes, you’ll see it travel up the kitchen roll and down into the cup where the colours will mix.
This clever experiment teaches kids about the capillary action, which is what plants use to pull water up from the soil and into their leaves to stay hydrated. Put simply – rather than being pulled down by gravity – the water travels from one cup to the other by moving up the paper towel, and into the glass next to it. You’ll need to exercise a little bit of patience to see the results, but we promise it’s worth the wait!