WHAT YOU NEED:
- A bicycle
- 2 small clear containers with lids (about
the size of a film canister is perfect!)
- Sticky tape
WHAT TO DO:
1. In a jug, mix three parts oil with one part vinegar and a little bit of mustard.Pour the mixture into your two containers and put the lids on.Seal the lids securely with tape.
2. Shake both bottles as hard as you can for at least 10 seconds!The mixture should be cloudy and everything should be mixed together.One of these bottles will go for a spin, the other will be your control bottle (so you can see the difference at the end!).
3. Turn your bike upside down so it’s resting on the seat and handlebars.Tape one of your bottles to one of the spokes on the back wheel.Tape it with the base as close to the rim as possible.
4. Using your hands, spin the pedals of your bike as fast as you can for at least 30 seconds to give your bottle a good spin.Mind your fingers and make sure you wait for the wheel to stop spinning completely!
5. Once the wheel has stopped spinning, untape your bottle and compare it with the control bottle – what’s happened?You should notice that the oil, vinegar and mustard have separated out!
The Extreme Science behind this:
In this experiment, you’ve used your bike
as a centrifuge!A centrifuge is a high
speed machine that scientists sometimes use to separate mixtures out into the
various substances they contain.
Your mixture was made up of oil, mustard
and vinegar.Each of these ingredients
contain particles of different sizes and weights – and when you spun them
around on your bike wheel, the heavier particles were pushed to the bottom of
the mixture more forcefully than the lighter particles.
That’s how you end up with three layers –
the mustard is the heaviest so it’s at the bottom.The vinegar is in the middle and the oil is
the lightest so it’s at the top.