Hello West Green!
It’s Robyn here! I hope you are all well. I’m taking some time away from the school office and wanted to share a fun experiment with you that I have done at home with my children.
You will need:
– a sheet of kitchen roll
– coloured felt pens
– a paper clip
– two small cups/bowls
1. Cut your piece of kitchen roll into the shape of a rainbow. Ask a grown-up to help you.
2. Colour the rainbow with the coloured felt pens about 2cms up on both sides.
3. Attach your paper clip to the top of your rainbow and tie a piece of string to it. This will give you something to hold or hang your rainbow with.
4. Fill each cup/bowl with water.
5. Hold or hang your rainbow with the ends slightly submerged in the water, then watch your rainbow grow!
Here is a little video of our rainbow as it grows! 🌈
A brief introduction to ‘capillary action’! Water molecules like to stick to things – including themselves. Sticking to things is called adhesion and sticking to itself is called cohesion. The fibres in the kitchen roll make lots of little holes. Water is ‘sucked’ through the holes because of adhesion (liking to stick to other things) and cohesion (liking to stick to itself) which makes the rest of the water follow. The water pressure will eventually slow down and the pressure of gravity will mean it stops moving.
How tall did your rainbow grow?
If you try the experiment at home please take a picture or video and send it to the school email address firstname.lastname@example.org or write me a comment below. I would love to here from you!
Stay safe! 🌈