This is a simple experiment with quick results. As with all experiments, please check with one of your adults that they are happy for you to try this. Tell them what’s involved, what you need, and where you plan to conduct it.
Tina’s Hypothesis
It is possible to ‘grow’ a rainbow with water, kitchen towel and water-soluble textas/felt-tipped pens.
Equipment
You will need:
- A sheet of regular A4 paper
- Kitchen towel (the paper sort that comes on a roll)
- A dish long enough to fit the whole edge of a piece of kitchen towel.
- Water
- Water-soluble textas of different colours
Method
1. Place the regular sheet of paper on a table or bench (this is to protect the surface from getting marked).
2. Rip a single piece of kitchen paper towel from the roll and place it flat on top of the protective paper.
3. Using your coloured textas, draw a thick line of alternating colours in rainbow order at one edge of the kitchen towel. (Because kitchen towel is thin, be careful not to make holes in it as you make your thick line. This is also why we’re using protective paper underneath.) Rainbow order, in case you’ve forgotten, is: Red, Orange, Yellow, Green, Blue, Indigo (dark purple) and Violet (light purple).
4. Pour some water into the bottom of the dish.
5. Gently lower the edge of the paper (closest to the line of colour) into the water.
6. Hold the paper just in the water.
7. Watch what happens!
Contributing Scientist: Tina S
Results and Conclusion
When you’ve done the experiment and found out if Tina’s hypothesis was correct or not, feel free to share your results – what happened – and your conclusions – what you found out – by telling us about it in the comment box below.
Is there anything you’d do differently next time?
Things to Think About When You Test it a Second Time (because you are going to test it again, aren’t you? I did!)
How long does it take for the rainbow to get to the top of the piece of towel? (Does it even get there?)
Do you think it would work if you used permanent markers? Or pencils? Or crayons?
And what if you drew a thin line? Or an extra thick one? Does this make any difference to what happens?
What works better – drawing your coloured line right at the very bottom of the paper, or leaving a gap between the bottom and the line?
Do some colours move faster than others? And why do you think the colours ‘walk’ up the paper anyway?
Have fun experimenting!
Kesta
I love art so this was the perfect experiment for me. I tried it with a line of different colours and watched my rainbow grow. I then also did it again but made a flower picture, when I put it in the water the flower grew!
I love the idea of making a flower grow! Very creative! I’ll have to try that myself.
I found that some colours are actually made up of lots of colours. When I tried black it separated out to show pink and purple colours!
That sounds cool, Harry. I wonder if anyone else will discover the same when they try this experiment.
That was really fun. I found that the orange went mostly all over the water and the water turned orange. I drew my colours in a zig zag and they went all straight up the paper towel.
Glad you enjoyed it Maia! That happened for me to the first time I tried it. I discovered that the colour bleeds down into the water if the line is drawn right at the very bottom of the paper and actually touches the water, but if you leave a space between the bottom of the paper and the coloured line, the colours travel up the paper instead of down into the water. If you want, have another go to test this out. Well done 🙂