Pepper and salt

Scatter some coarse salt onto the table and mix it with some ground pepper. How are you going to separate them again?
Rub a plastic spoon with a woollen cloth and hold it over the mixture. The pepper jumps up to the spoon and remains sticking to it. The plastic spoon becomes electrically charged when it is rubbed and attracts the mixture. if you do not hold the spoon too low, the pepper rises first because it is lighter than the salt. To catch the salt grains, you must hold the spoon lower.