I am heartened by the beautiful images of rainbows which are appearing in windows across the country. The images on social media and in the windows of the houses I pass on my run, bring a welcome smile to my face. They have left me thinking about colourful science experiments that can be done at home to create smiles, evoke awe and wonder and provide a welcome distraction from some of the challenges we are all facing at this moment in time.
Here are a few simple and colourful science experiments that can be done easily with children at home:
Skittles - creating a rainbow
It turns out that not only can you taste the rainbow with skittles you can also make it. Place some skittles around the outside of a white plate and pour water on the plate so the skittles are covered with water and watch what happens.
The colour and sugar of the skittle dissolve into the water and then spread throughout.
(This is just the start, it gets better)
Questions to ask children: What do you notice? What questions does this make you think of?
This activity can even be turned into an enquiry such as: How does the temperature of the water affect the time taken for the colour to reach the centre of the plate?
Magical Cabbage - colour changing liquid
For this experiment, you will need to make the magical red cabbage liquid or indicator first. To do this, finely chop, grate or blend a red cabbage and put into a saucepan. Add some boiling water and then simmer for around 10 minutes. Sieve the pieces of cabbage out and leave the purple/blue cabbage indicator to cool before using. This will last a couple of days in the fridge and can also be frozen if you want to use at a later date.
How it works: The red cabbage contains a pigment called anthocyanin, which changes colour in acids and alkalis, acting as an indicator. It turns red in acid, purple in a neutral solution and blue or green in alkali.
Using your indicator: In a glass, add a small amount of one of the suggested substances below and see what colour it makes. In separate glasses, test the other substances and see what colours of the rainbow you can make.
(Suggested substances: water, milk, lemon juice, vinegar, lemonade, toothpaste, bicarbonate of soda or baking powder, washing up liquid.)
These are my results.
If you don’t have red cabbage you can also make an indicator with beetroot juice or blackberries.
Nature rainbow hunt
This activity involves going on a hunt in a garden or outdoor area to find all the colours in the rainbow. This is what I managed to find in my garden:
Questions to ask children: Can you find all of the colours in the rainbow in your garden? What colours are difficult to find at the moment? Why might this be?
Animal rainbow hunt
This activity requires the internet or a good range of books of animals to find different animals for each colour of the rainbow.
Questions to ask children: Can you find an animal for each colour of the rainbow? What is the most colourful animal you can find? Why are some animals colourful and some not?
Simple kitchen roll chromatography
You may remember chromatography from secondary school days. It is a method for separating the component parts of a dye or ink and works well with water-soluble felt tip pens.
The Royal Institute has some wonderful videos showing parents investigating science with their children at home. In one of these, they show how easy it is to do chromatography at home with just kitchen roll and water-soluble pens. Check out their colour quest video to find out more.
Rainbow in a glass
This experiment involves using different coloured liquids with different densities to make a mini rainbow in a glass.
What you will need: syrup or honey, washing up liquid, coloured water (with food colouring or squash), oil and a clear glass.
First, add a small amount of golden syrup to the glass, trying to avoid getting any on the side. Next, carefully drip some washing up liquid on top by letting it run down the side of the glass. After this, slowly add coloured water on top in the same way and finally add a small amount of oil. You should now have a liquid rainbow with four layers separated according to density with the least dense at the top.
(My attempt in my kitchen. Made from syrup, shampoo, blue water and oil. Green washing up liquid would have been more colourful but as my washing up liquid is clear I went with the white shampoo instead.)
Questions to ask children: Why does the oil sit on top? Do you think the order the liquids are added matters? If we drop in something that floats in water, where will it sit? If we do drop in something that sinks in water, where will it sit?
Science is all about asking questions so if all this talk about rainbows has made you curious about the real thing, check out the Met Office website for more information.
Have fun making your own science rainbows. Keep the scientific flame alive by talking about what you notice and keep asking questions.
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