4.2 Charge on the MoveApril 21, 2023

•Conductors cannot become charged when electrons are free to move to Earth.

•Charge is carried by electrons moving through conductors. This flow is called an electric current.

•A build up of charge can produce sparks.

What is a water current?

Try to describe in less than 20 words what a water current is.

5 minutes!

In Denmark in 2004, 31 cows were killed by one bolt of lightning. They were sheltering under a tree during a storm. Why is lightning more dangerous for creatures with 4 legs than 2?

Electric current

• In an electric circuit electrons flow.• Electrons have a ___________ charge.• Positive charges can only move in a

liquid or gas.electrons

Gold Leaf ElectroscopeDiagram

This device measures charge. Electrons can flow through the metal parts when a charged object is brought near the metal cap. The gold leaf moves because it has the ______ charge as the rod.

Surviving LightningLightning is caused when the charge on the cloud is connected to Earth – We say the charge is Earthed. The charge will take the easiest route. Air is a bad conductor. Most other materials are better conductors.

Why is a prayer position the best position to adopt in a lightning storm?

A small current (.05A) through the heart is enough to stop it.

Dangerous Sports

Which are the most dangerous sports in a thunderstorm? Can you explain why?

Many people are killed every year playing sports in thunderstorms. Some sports are more dangerous than others.

Answer the summary questions on page 163

4.2 Charge on the MoveApril 21, 2023

•Conductors cannot become charged when electrons are free to move to Earth.

•Charge is carried by electrons moving through conductors. This flow is called an electric current.

•A build up of charge can produce sparks.