|Separating the pepper from a mixture of salt and paper using a ruler.
|Grade 6 - Energy in Our Lives
Grade 9 - Using Electricity
A piece of paper
A plastic ruler
Wool (100% if possible)
Put some salt and pepper into a petri dish, and put on the lid. Use the wool to rub the top of the dish and the pepper will stick to the lid, leaving the salt on the bottom of the dish.
On the piece of paper, sprinkle a pile of salt and pepper. Make sure the salt and pepper are mixed. Ask, "How can I separate the pepper and the salt?" Rub the plastic ruler with the wool. Hold the ruler close to the paper and watch the pepper stick to it.
|No safety concerns. Allergies to wool and pepper may need to be considered.
|Make sure the top of the petri dish (or ruler) is well charged. You should be able to hear the static building. Hold the ruler fairly close to, but not touching, the paper. If it is too far away, the experiment will not work.
When the ruler is rubbed with the wool, the electrons from the wool are left on the ruler. The negatively charged ruler passes near the neutral pepper particles and becomes positively induced. The pepper particles "fly" up to the ruler. If you listen closely, it sounds like static electricity.
NOTE: Another way to separate the salt and pepper is to put the mixture in a beaker of water. The salt will sink and the pepper will float.
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