Electricity

Have you ever stuck a balloon to the wall after rubbing it on your head? Have you ever stuck a balloon to the wall after rubbing it on your head? Has your fleece ever made crackling noises when you took it off? Has your fleece ever made crackling noises when you took it off? Have you ever got an electric shock off your door knob? Have you ever got an electric shock off your door knob? Have you ever seen lightening? Have you ever seen lightening?

All these things happen because of Static Electricity

What is Static Electricity? Static electricity occurs when there is a build up of electric charge on the surface of a material. Static electricity occurs when there is a build up of electric charge on the surface of a material. It is called static electricity because the charges don’t move. It is called static electricity because the charges don’t move. The electricity we use everyday involves moving charges. The electricity we use everyday involves moving charges.

What is charge? To understand charge we have to look at things on an extremely small scale. To understand charge we have to look at things on an extremely small scale. We have to try and understand things that we can’t even see with the most powerful microscope. We have to try and understand things that we can’t even see with the most powerful microscope. Atoms!

The atom Everything we see around us everyday is made of atoms. Everything we see around us everyday is made of atoms. We can’t see individual atoms because they are so small. We can’t see individual atoms because they are so small. In fact the diameter of an atom is about m In fact the diameter of an atom is about m In the air in your classroom there are about atoms. In the air in your classroom there are about atoms.

What is inside the atom? The atom is made of 3 sorts of particles. The atom is made of 3 sorts of particles. The electron The proton The neutron We can imagine each as a tiny little ball. We can imagine each as a tiny little ball.

Inside an atom The protons and neutrons sit together in a lump in the middle called the nucleus. The protons and neutrons sit together in a lump in the middle called the nucleus. The electrons orbit around the nucleus, a bit like the planets orbiting the Sun. The electrons orbit around the nucleus, a bit like the planets orbiting the Sun. Most of the atom is empty space if atoms were the size of football fields, the nucleus would be a grain of sand in the middle and the electrons would be orbiting around the edge..

Charge The electron is negatively charged. The electron is negatively charged. The proton is positively charged. The proton is positively charged. The neutron has no charge, it is neutral. The neutron has no charge, it is neutral.

Charge Most things have the same number of electrons and protons in them. Most things have the same number of electrons and protons in them. They don’t have any overall charge. They don’t have any overall charge. Electrons can move and cause a charge Electrons can move and cause a charge Static electricity is the imbalance of Static electricity is the imbalance of positive and negative charges.

How do charges behave? What do you know about magnets? What do you know about magnets? 2 north poles will repel each other, but a north and a south put together will attract one another 2 north poles will repel each other, but a north and a south put together will attract one another

How do charges behave? Exactly the same thing happens with charges. Exactly the same thing happens with charges. 2 positive charges put together will repel each other. 2 positive charges put together will repel each other. Put a positive charge near a negative charge and they will attract each other. Put a positive charge near a negative charge and they will attract each other. A charged object may even attract a neutral one. A charged object may even attract a neutral one.

FRICTION FRICTION Rubbing one object on another object Rubbing one object on another object causes electrons to be passed from the first object to the second causes electrons to be passed from the first object to the second CHARGING OBJECTS

Conduction Conduction one object comes in contact with another object one object comes in contact with another object causes electrons to be passed from the first object to the second causes electrons to be passed from the first object to the second CHARGING OBJECTS

Induction Induction one object comes close to another object one object comes close to another object causes electrons to be rearranged on the second object causes electrons to be rearranged on the second object

Induction Pith Ball Demonstration Pith Ball Demonstration Pith Ball Demonstration Pith Ball Demonstration

Lightning

What causes lightning? Lightning is actually just static electricity on a much larger scale. Lightning is actually just static electricity on a much larger scale. The rubbing is caused by air moving around The rubbing is caused by air moving around In thunderclouds bottom is usually negative and top is positive. In thunderclouds bottom is usually negative and top is positive.

Thunder When the lightning flash happens it heats the air to a temperature 5 times hotter than the surface of the sun. When the lightning flash happens it heats the air to a temperature 5 times hotter than the surface of the sun. This causes nearby air to expand and vibrate forming the sound we hear as thunder. This causes nearby air to expand and vibrate forming the sound we hear as thunder.

Interesting facts Lightning bolts can travel at speeds of up to 60,000 miles per second. Lightning bolts can travel at speeds of up to 60,000 miles per second. Every second around 100 bolts of lightning strike the Earth. Every second around 100 bolts of lightning strike the Earth. One lightning bolt has enough electricity to power 200,000 homes. One lightning bolt has enough electricity to power 200,000 homes. You are more likely to be struck by lightning than be eaten by a shark. You are more likely to be struck by lightning than be eaten by a shark.

Some myths Lightning never strikes in the same place twice. Lightning never strikes in the same place twice. False, the Empire State Building is reportedly struck 100 times a year. False, the Empire State Building is reportedly struck 100 times a year. Wearing rubber shoes will protect me in a thunder storm. Wearing rubber shoes will protect me in a thunder storm. False, Lighting is too powerful to be stopped by half an inch of rubber or several hundred feet of rubber for that matter. False, Lighting is too powerful to be stopped by half an inch of rubber or several hundred feet of rubber for that matter.

Static Electricity Rare Occurrence or Common Hazard?

Rare or Freak Accident?

The photo before shows the results of a static electricity discharge at a Chevron gasoline station in Salt Lake City, Utah, USA (January, 2003) The photo before shows the results of a static electricity discharge at a Chevron gasoline station in Salt Lake City, Utah, USA (January, 2003) It started from static electricity. The customer, a teenage girl, started pumping gasoline using the automatic filler, and got back in the vehicle. When the pump clicked off, she got back out of the car and didn't ground herself. She said she saw a blue flame jump from her hand to the pump nozzle. The photos show the damage to the vehicle and nearby equipment. The girl was not injured. It started from static electricity. The customer, a teenage girl, started pumping gasoline using the automatic filler, and got back in the vehicle. When the pump clicked off, she got back out of the car and didn't ground herself. She said she saw a blue flame jump from her hand to the pump nozzle. The photos show the damage to the vehicle and nearby equipment. The girl was not injured. Cold, dry weather can produce the ideal conditions for a static discharge. Cold, dry weather can produce the ideal conditions for a static discharge.

Safe Refueling and Fuel Handling Guidelines Here are some refueling and fuel safety guidelines that will help keep you and your family safe when refueling your vehicle or filling up gasoline storage containers: Here are some refueling and fuel safety guidelines that will help keep you and your family safe when refueling your vehicle or filling up gasoline storage containers:

Safe Refueling and Fuel Handling Guidelines Turn off your vehicle engine while refueling. Put your vehicle in park and/or set the emergency brake. Disable or turn off any auxiliary sources of ignition such as a camper or trailer heater, cooking units, or pilot lights. Turn off your vehicle engine while refueling. Put your vehicle in park and/or set the emergency brake. Disable or turn off any auxiliary sources of ignition such as a camper or trailer heater, cooking units, or pilot lights. Do not smoke, light matches or lighters while refueling at the pump or when using gasoline anywhere else. Do not smoke, light matches or lighters while refueling at the pump or when using gasoline anywhere else.

Safe Refueling and Fuel Handling Guidelines Use only the refueling latch provided on the gasoline dispenser nozzle, – never jam the refueling latch on the nozzle open. Use only the refueling latch provided on the gasoline dispenser nozzle, – never jam the refueling latch on the nozzle open. Do not re-enter your vehicle during refueling. Do not re-enter your vehicle during refueling. In the event a static-caused fire occurs when refueling, leave the nozzle in the fill pipe and back away from the vehicle. Notify the station attendant immediately. In the event a static-caused fire occurs when refueling, leave the nozzle in the fill pipe and back away from the vehicle. Notify the station attendant immediately. Do not over-fill or top-off your vehicle tank, which can cause gasoline spillage. Do not over-fill or top-off your vehicle tank, which can cause gasoline spillage.

Potential Cell Phone Hazard Combustible Gases + Cell Phones = Explosions TURN OFF CELL PHONES BEFORE ENTERING SITES WITH POTENTIAL EXPLOSIVE MIXTURES

BACKGROUND An employee on an offshore drilling rig received second degree burns when he answered his cell phone while working on a panel which contained an explosive mixture of gas. Similarly, a driver suffered burns when gasoline fumes ignited causing an explosion as he was talking on his mobile phone while his vehicle was being fueled. Many mobile phone makers print cautions in their user handbooks that warn against mobile phones in gas stations, fuel storage sites, and chemical factories.

Best Practices Read your instruction book. Mobile phone makers such as Motorola, Ericsson, and Nokia print cautions in their user handbooks that warn against mobile phones in gas stations, fuel storage sites, and chemical factories. Turn off your mobile phone before entering any area with a potentially explosive atmosphere (For example: areas around degas wells; coal storage areas; fueling areas, such as gas stations; below deck on boats; fuel transfer storage facilities; chemical transfer and storage facilities; and areas where the air contains chemicals or particles, such as coal dust, grain, dust, or metal powders). Do not transport or store flammable gas, liquid, or explosives in the same compartment of your vehicle that contains your mobile phone and its accessories.