9.5 Applications of Static Electricity

Applications of Static Electricity Lightning Laser Printers - Ink jet printers use static electricity to guide a tiny jet of ink to the correct place on the page. Laser printers work in a similar way. Fabiric Softener Sheets and Static cling Pollution control; Electrostatic Precipitators- by applying a static charge to dirt particles in the air and then collecting those charged particles on a

Lightning p288 Clouds contain millions of water droplets that collide with other droplets as they rise and fall. During the collisions, electrons are transferred from the rising water droplets to the falling water droplets. The negatively water droplets collect in the lower pare the cloud, giving it a negative charge. The positive water droplets continue to rise, carrying the positive charge to the top of the cloud. Creating a separation of charge. As separation of charge becomes more intense, eventually the electrons at the surface of the Earth are repelled by the strong negative charge at the lower part of the cloud. Causing Earth’s surface to become positive. In effort to neutralize the charge separation, a pathway of electrons flow between Earth and cloud. Moving electrons excite surrounding air, causing flash of light and high heat Heat causes rapidly expanding air to send out a shock wave - thunder

Laser Printers Printer sends information to laser device, which emits light that is reflected onto a drum Drum has positive charge. Light from laser causes negative charge on the drum in shapes of te letters, “writing” images on the drum. Drum is rolled onto a reservoir of toner, (fine powdery mixture of black pigment and plastic. Toner has a positive charge so it stick to the negative areas of drum. Like glue on a pop can collecting flour. Paper is given a strong negative charge, rolls under drum, picking up toner from drum. Paper passes through fuser that heats toner, melting it to page

Fabric Softeners Hot, dry environment, lots of friction Rubbing of different fabrics causes charges. Fabric sheets contain a chemical that is attracted to negatively charged clothes. Coats the surface, leaving them feeling soft. Neutralizes the negative charges, and reduces friction by coating the clothes. Toxic, Better to use clothes line – no static build up

Electrostatic Precipitators in Smokestacks Smoke from stack is given an electric charge. When it passes by electrodes of the opposite charge, most of the smoke particles cling to the electrodes. This keeps the pollution from going out into the atmosphere Also used to remove wood dust in pulp mills

Air fresheners Some people purchase what are called air ionizers to freshen and purify the air in their homes. They work on a similar principle as the smokestack pollution control. These devices strip electrons from smoke molecules, dust particles, and pollen in the air, just as what happens in creating static electricity. These charged dust and smoke particles are then attracted to and stick to a plate on the device with the opposite charge. After a while, much of the pollution is drawn from the air. Since charged particles will also stick to neutral surfaces, some of them can stick to the wall near the ionizer, making it very dirty and difficult to clean.

Painting cars Paint given an electrical charge. The charged paint particles are attracted to the car and stick to the body, just like a charged balloon sticks to a wall. Once the paint dries, it sticks much better to the car and is smoother because it is evenly distributed. Some automobile manufacturers use static electricity to help them paint the cars they make. The way this works is that they first prepare the car's surface and then put it in a paint booth. Paint given an electrical charge and then spray a fine mist of paint into the booth.

Homework Read pages 288-289 Answer CYU p 290, # Chapter 9 Test: April…..