Teaching people about science is kinda a thing I like to do. So when my son asked the other week “Daddy, can I do science with you?” it should come as no surprise that I immediately cleared my schedule and started planning some ‘science’
Of course he did kind of ruin the moment by following it up with “I want to make a magic potion” but I’m choosing to ignore that bit.
My first instinct when thinking of doing home science was to buy one of the cool science kits I had as a kid. The ones with the purple methylated spirits and the array of strange chemicals that let you make stains on your parents kitchen table that nothing would ever shift. But when I looked around teh internets there was a singular lack of decent science kits. The only one that looked half decent was pretty pricey for a load of cheap looking plastic and clearly aimed at kids 10+ not 4.
After browsing around for disappointing chemistry kits my brain finally clicked in to gear and pointed out that I already have a kitchen full of random food-chemicals. So after a little brainstorming I came up with 3 cool experiments to do with kids, of almost any age, in the kitchen.
I’ve made purest green!
This is about the easiest experiment I could come up with but is a great place to start. It has the benefit of being a really visual experiment and teaching them about how colours are made.
- 3 x things that can hold liquid
- Some blue food dye
- Some yellow food dye
- Fill two of the liquid holding devices about 1/3 full of water. Mix a little blue food dye into one and yellow into the other.
- In one fluid motion pour the two dyed liquids into the empty container
- Marvel and the green liquid you’ve created
This one has a secret agenda that is designed to make your small person realise why soap is important. Like most hidden educational messages I suspect it will be totally ignored, kids don’t learn well from subtlety. The basic principle here is that oil and water don’t mix but oil, water and soap/washing up liquid does!
- 2 x glass or plastic bottle
- Cooking oil
- Some kind of fruit juice
- Fill the bottles about 1/2 full with water
- Pour a good slug of fruit juice into one of the bottles
- Give it to your small person to shake and try to mix it.
The fruit juice (primarily made of water) will mix really easily with the water because the fruit juice is full of things that are hydrophilic (like water).
- Pour in a little oil in one bottles (enough to form a nice 0.5cm layer on the water)
- Give it to you small person to shake and try to mix it.
The lighter density hydrophobic oil will preferentially try to escape from the water and so will form a layer on the top of the surface. When your small person tries to shake and mix the two liquids they’ll find that no matter how hard they shake it will always separate back out. This is because the oil is made up of molecules that are hydrophobic (think water is a horrible meany).
- Add a drop or two of washing liquid or liquid hand soap to the oil-water bottle
- Give the bottle back the small person and ask them to try mixing it again
The oil should now partially mix with the water creating a cloudy solution (with an oily top). The soap helps the oil mix with the water by forming micelles (surrounding the oil droplets like a coat) so they can mix with the water without having to go near it.
For those who don’t read my blog regularly, vortex rings are the science equivalent of my white whale. I have written about how their exact formation has eluded me several times. But they look pretty so we’re going to do them.
- Syringe/dropper anything that can form a little drop of water on the end
- Bowl of water
- Bowl of food dyed water
- Fill the syringe/dropper with the dyed water
- Using the syringe/dropper squeeze out a drop so that it hangs of the end off the dropper
- Slowly touch the drop to the surface of the water
When the drop touches the water it should fall off the tip of the syringe and form a coloured vortex ring that shoots to the bottom of the bowl. The reason why is a little vague as I think I have previously covered…at length, we don’t really know why this happens.