Challenge your kids to separate a mixed pile of salt and pepper! It might seem impossible, but sometimes the impossible is possible with a little science! While you might enjoy the thought of several quiet minutes of them parsing through the salt and pepper grains, the task might grow tedious, but by adding a bit of static electricity you can sort the mess in just a few seconds! My boys thought is was some kind of joke until I showed them the trick.
What you need:
- Wool or the hair on your head
What you do:
- Sprinkle some salt and pepper on a plate.
- Mix them up evenly.
- Rub a comb briskly through your hair or on a piece of wool.
- Slowly hover the comb teeth side down over the mix of salt and pepper.
- Watch the pepper jump!
Why does it work?
The static electricity on the comb has a negative charge. Because salt and pepper are positively charged and opposites attract, the pepper jumps up onto the comb. But why not the salt? Salt is much heavier than pepper, and the charge is not strong enough to lift the salt. Buzz, snap, jump and you have sorted the salt and pepper.