Electric forces: static electricity
Answers are for parents and teachers.
1
On a dry day, rub a plastic comb on dry hair and try to pick up tiny paper bits. Describe what happens and what you think the comb gained or lost.
Answers differ. The paper jumps to the comb if the air is dry. The comb gained or lost electrons.
2
A balloon becomes negative when rubbed on wool. What charge does the wool get, and why?
Positive: the wool lost the electrons that the balloon gained.
3
Write three safety rules for a thunderstorm and say why one of them is important.
Stay indoors, do not shelter under a tree, and do no experiments. A tree is tall, so lightning is more likely to strike it.
4
Draw a positive and a negative charge and show the field lines between them with arrows.
Arrows go from the + to the − and they do not cross.
5
Describe the path of lightning that strikes a building with a lightning rod, from the cloud to the ground.
Cloud, pointed rod, thick metal wire, metal plate in the ground. The building itself is not on the path.