TOPIC: Electricity AIM: How is static electricity formed? DO NOW: Using your knowledge of atoms and electricity, describe how the static electricity is being formed in this picture

Don’t forget… Opposite charges attract Like charges repel

Build up of electric charges in an object

Electrons are transferred from one object to another. A buildup of charges occurs. The electrons stay for a while. They will eventually leave, and the object will become neutral once again.

Compared to the electrons in carpet atoms, electrons are bound more tightly to the atoms in the soles of your shoes. When you walk on the carpet, electrons are transferred from the carpet to the soles of your shoes. The soles of your shoes have an excess of electrons and become negatively charged. The carpet has lost electrons and has an excess of positive charge. The accumulation of excess electric charge on an object is called static electricity.

When you run 2 balloons on your hair, they pick up electrons & become negatively charged. They are then attracted to the positive charges on the wall. When placed close together, the 2 balloons repel each other.

Pull the clothes out of a clothes dryer just after they have stopped tumbling. The clothes may stick together. The rubbing, tumbling, and brushing all strip electrons from one object and transfer them to another. One object has gained electrons or a net negative charge. The other object has a shortage of electrons or a net positive charge and they are attracted to each other.

Van de Graaff generator: When a person places their hand on the static ball, excess charge from the ball is shared with the body. The excess charge flows to the body and spreads throughout the surface of the body, even onto strands of hair. As the individual strands of hair become charged, they begin to repel each other. Looking to distance themselves from their like-charged neighbors, the strands of hair begin to rise upward and outward - a truly hair-raising experience.

Loss of static electricity Electric charges move off object Example: Lightning

Lightning forms when electrons shoot through the air so fast they make the air around them glow. A streak of lightning always shows the path electrons followed.

Storm clouds form when humid, warm air rises and meets a layer of cold air and mix together  buildup of charges. Convection currents in the cloud separate the charges. Lightning strikes when negative charges at the bottom of the cloud are attracted to positive charges on the ground. Electrons move toward the ground & attract positive charges that surge upwards  lightning flash.

Grounding Connecting object to Earth with a conductor Provides path for charge to reach Earth Prevents buildup of charges

Example: Lightning Rods (usually made of metal)