Exploring Charges Post Lab

What did the balloon simulation teach us? Opposites Attract and Likes Repel Charged objects can be attracted to neutral objects Because electrons inside the neutral object can move within it Electrons can be transferred from one object to another Some charges are stronger than others

What did we learn from JJ Thomson (cathode ray tube)? Electrons are in the atom Electrons are charged Electrons are negative Electrons can move

The Conductivity Demo Electrons can move more freely in some substances than others Metals --- electrons move very well Evidence: electric wires are metal, salt water and other solutions made from metals conduct Non-metals ---- not so well Evidence: some lights were dim; some solutions Some substances not at all Evidence: dry substances that are not metals did not conduct

Charged Objects vs Nonmetals How will the electrons move? • • • Electrons in non-metals do not move very freely. They can move but not completely away from the nucleus.

Charged Objects vs Metals How will the electrons move? • • • Electrons in metals can move very freely. They can move completely away from the nucleus.

What’s the bottom line? Electrical forces are involved in holding together the particles that make up pure substances. Negative particles can move Positive particles can NOT move Mobile electrons are freer to move in some substances than in others.