What IS STATIC ELECTRICITY?

Lesson 1 – Static Electricity Houghton Mifflin Book F Chapter 15 Lesson 1 Pages F44 – F47

Essential Questions How can energy be transferred from one material to another? What happens to a material when energy is transferred to it? Pair Share: Take a few moments to discuss these essential questions with your partner.

Main Idea All matter is made up of tiny particles, some of which carry positive or negative electric charges. Objects can be neutral or have a negative or positive charge.

Electric Charges All matter, including hair and combs, is made up of tiny particles called atoms. Atoms are made up of even tinier particles. Many of these very tiny particles carry units of electricity called electric charges. These charges can make your hair stand on end or they can give you a shock.

Two Kinds of Electric Charges There are two kinds of electric charges, positive and negative. Charges that are the same are called like charges. Charges that are different are called unlike charges. Most matter is electrically neutral. This means it has an equal number of positive and negative charges.

How Charges Behave Like charges repel, or push away from each other. Unlike charges attract, or pull toward, each other. Two objects with the same charge will push away from each other. Two objects with opposite charges will pull toward each other.

More About Charges Particles that have a negative charge can move more easily from one material to another than particles with a positive charge can. Negative charges are attracted to positive charges.

Get those Negative Charges Moving Negative charges usually don’t move toward an object that is electrically neutral on their own. However, negative charges can be made to move. Rubbing can move negative charges from one neutral object to another. For example, rubbing a balloon with a wool cloth causes negative charges to move from the cloth to the balloon.

Buildup and Discharge Sometimes a charge builds up on a material. This built-up electric charge is called static electricity. When your hair stands on end and moves toward a plastic comb; that is static electricity at work.

Why might your hair stand on end when you comb it? 1. Combing your hair rubs the teeth of a comb against strands of your hair. 2. As a result, negatively charged particles move from your hair onto the comb. This gives the comb an overall negative charge. 3. Once your hair loses negatively charged particles, it has an overall positive charge. 4. Since the hair and the comb have opposite charges, they attract each other. 5. At the same time, each strand of hair has a positive charge. The strands repel each other and stand up.

An Experiment with a Comb and Some Paper

PAIR SHARE Why do you think you feel a shock from a metal doorknob after walking on a carpet?

It’s Shocking! You sometimes get a shock when you touch a metal doorknob. The shock is due to electric discharge. A negative charge builds up on a person. When the person touches the doorknob, the charge quickly jumps from the person to the doorknob. This release of the built-up negative charge is called an electric discharge, or spark.

Group Talk Q: Suppose you pull a shirt from the dryer, and it has a sock stuck to it. Explain how this happens. A: Clothes rub together in the dryer, causing charges to move and giving the clothes opposite charges, which attract.