Science study guide !! test Nov. 3rd

Fill in the Blank

Electroscope diagram

charging by contact diagram

Application questions:  lightning, static electricity in the home, explain a class demonstration \n \n \n \n \n

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• As a storm moves closer, the time between lightning and thunder decreases. This is because lighting travels at the speed of light, and thunder does not, traveling at the speed of sound. If you are hearing both at the same time, a storm is above you.
• Lightning can strike up to 15 KM from where it is raining. Shelters, such as large buildings, cars, school buses, and other vehicles provide proper grounding and are the safest place to be during a storm. If no safe shelters are available, it is important for you to be at a lowland because of the tendency of lightning to strike highest points.Anything that conducts electricity should be stayed away from. \n Lighting is a very dramatic example of grounding. When clouds are heated and cooled by the air, friction is experienced along with p+ and e- charges. Water droplets connect charged clouds with ground, and when grounded the e- move quickly between the two appearing as lightning.
• Lightning causes about 6 deaths and 60 injuries per year in Canada, posing as a threat that could be prevented by just following safety regimens
• Metal poles, known as lightning rods, have wires attached to them that run down to the ground. The main point of using a lightning rod is to provide a point where electrically charged particles are more likely to go. In using a lightning rod, it decreases a total amount of electric charge in a building, making it less likely to be struck. This also helps to ground the building and electrically charged particles.

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When insulators (i.e nylon, polyester) are rubbed together they create static charges. This is why clothes often come out of a clothes dryer stuck together. Dry air can provoke more charges, as it acts as an insulator. If you remove clothes before they are completely dry, there will be fewer charges too.

Sometimes, adding a dryer sheet helps with the static charges. This adds a thin layer of waxy chemicals to the surface of clothes, making less friction between the surfaces. \n \n Sparks caused by static charges can damage sensitive electronic equipment. People who work with this equipment take special precautions to reduce the risk of sparks. A carpet can cause static buildup. \n Ways to reduce the risk of static sparks from carpets include:

• Using an antistatic mat for your feet

• Increasing the moisture in the air by using a humidifier

• Spraying the carpet with antistatic spray

• Wearing an antistatic wrist strap

• Removing a carpet from the computer room

  \n \n Charging by contact vs charging by Induction

• Charging by contact = touching the object directly (i.e in this case metal sphere)

• Charging by Induction = not touching the object directly \n

  \n  - LIGHTNING DIAGRAM  = lightning moves from cloud to earth when grounder, but also moves from earth towards a positive cloud when grounded.