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How Objects become Charged

Physical Science - Middle School

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There are several ways that an object can become charged, and electrons can be transferred. Friction is the transfer of electrons between two uncharged objects that are rubbing against each other. Induction is the movement of electrons within an object in response to an electric field of a charged object nearby. The electrons’ movement creates a charge in a certain area of the object. Static Electricity Static electricity occurs when electric charges build up on an object, but the electrons do not flow. Static electricity is what causes lightning. An excess of positive charges builds up on the ground while a large number of negative charges builds up in the clouds. At a certain point, the difference between the negatively charged cloud and the positively charged ground is so great that the static electricity turns into an electrical current. The bolt of lightning is actually a discharge of electrons traveling at the speed of light toward the positive charges. Electroscope An electroscope is an instrument used to detect charged particles. It has a long metal rod with a knob on top and two metal leaves attached to the bottom. The leaves hang straight down if the electroscope has no charge. If a charged object touches the knob and electrons are transferred, the metal leaves become charged. Because the leaves are the same charge, they repel each other and spread apart. The leaves will move in the presence of a negative or positive charge. Conduction is the transfer of charges when a charged object is in direct contact with another object. friction + + + + + + + conduction ++ + + + + induction metal rod metal leaves knob negatively charged metal rod metal rod metal leaves knob + + + + + + + + + + + knob positively charged glass rod metal rod metal leaves metal rod metal leaves knob negatively charged metal rod metal rod metal leaves knob + + + + + + + + + + + knob positively charged glass rod metal rod metal leaves How Objects Become Charged © Copyright NewPath Learning. All Rights Reserved. 94-4488 Visit www.newpathlearning.com for Online Learning Resources. In the 1700s, Benjamin Franklin studied lightning and electricity. He invented the lightning rod to protect buildings during storms. electroscope

How Objects Become Charged Pause and Review Add pluses (+) and minuses (-) to the pictures below to represent the presence of positive and negative charges. © Copyright NewPath Learning. All Rights Reserved. 94-4488 Visit www.newpathlearning.com for Online Learning Resources. Describe and illustrate: Friction ___________________________________ ___________________________________ ___________________________________ ___________________________________ Conduction ___________________________________ ___________________________________ ___________________________________ ___________________________________ Induction ___________________________________ ___________________________________ ___________________________________ ___________________________________

How Objects become Charged

Physical Science - Middle School

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