The electrical nature of matter: electrification

We rub a balloon against a T-shirt and, when bringing it close to small pieces of paper, they jump and stick to the balloon, as shown in the diagram.

What is this method of charging an object by rubbing it called? Explain in your own words what has happened to the balloon.

In winter, when taking off her woollen hat, Vega's hair stands on end and some hairs stick to the hat. Why does her hair stand on end and why do individual hairs separate from each other? Explain this using what you know about charges.

When going down a plastic slide, your body rubs against the surface. When reaching the bottom and touching the metal handrail, we sometimes feel a small electric shock. Explain step by step, from when we start going down, how this electric shock is produced.

How many types of electric charge are there and what are they called? Look at the two pairs of charges in the diagram:

Explain what happens when two charges of the same type are brought close together and what happens when two charges of different types are brought close together.

We rub two balloons with the same woollen cloth and bring them close to each other, as in the diagram.

1. a) Will they attract or repel each other?
2. b) Justify your answer by considering the type of charge each balloon has received.

Marcos brings a rubbed plastic rod close to a small cork ball hanging from a thread, as shown in the diagram.

The small ball moves towards the rod and touches it; immediately afterwards, it flies backwards. Explain why the ball first moves closer and then moves away.

Atoms have positively charged protons, negatively charged electrons and uncharged neutrons. An atom has $6$ protons and $6$ electrons, like the one in the diagram.

1. a) What is its total charge?
2. b) What type of charge will the atom have if it loses an electron?

When rubbing a balloon against hair, some of the charge transfers from the hair to the balloon, and the balloon is left with a negative charge.

1. a) What type of charge is then left on the hair?
2. b) Explain why, when slowly pulling the balloon away, some hairs stretch out towards it.

Andrea says: "When rubbing a balloon, new charge is created that did not exist before." Bruno replies: "It is not created: charge transfers from one body to the other, which is why the balloon and the cloth end up with different charges."

1. a) Who is right?
2. b) Support your answer by considering what happens to the two objects being rubbed.

State which of these objects allow electric current to pass through well (conductors) and which do not (insulators): an iron key, a plastic ruler, a coin, an eraser, a steel spoon and a wooden toothpick.

The inside of cables is made of copper and the outer sheath is made of plastic, as seen in the cross-section in the diagram.

Why are they not made the other way round, with plastic on the inside and copper on the outside? Give reasons for your answer using the words conductor and insulator.

A plug has a hard plastic casing and metal pins, as shown in the diagram.

1. a) What electrical property is required in each of the two parts?
2. b) What would happen if the casing were made of metal?
3. c) What if the pins were made of plastic? Explain whether the plug would work.