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Chapter 4, Lesson 1 Multimedia

Pencil Zoom

A three-tiered diagram of a pencil.  There is a close-up view of the graphite, showing carbon atoms, and then a close-up view of one of the carbon atoms, revealing the protons, neutrons, and electrsons of which it is composed.
  • The “lead” of a pencil is actually made of a substance called graphite which is made of carbon atoms.
  • The picture shows a close-up of one carbon atom.

Protons and Electrons

This animation demonsrates that two subatomic particles of like charge repel one another, while two subatomic particles with different charges are attracted to one another.

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  • Protons have a positive charge. Two protons repel each other.
  • Electrons have a negative charge. Two electrons repel each other.
  • A proton and an electron have opposite charges and attract each other.

Hydrogen Atom

This animation shows a simple model of a hydrogen atom. A single electron orbits around the nucleus of the atom. This model also offers a view of a diffuse electron cloud, which is the more widely accepted model of conceptualizing electron position in an atom.

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  • A hydrogen atom has one proton as the nucleus and one electron in the region outside the nucleus.
  • The electron and proton are attracted to each other. This attraction holds the atom together.
  • It is not possible to locate the exact position of an electron but the electron cloud shows the region where an electron is most likely to be.

Charged Plastic and Hand

A diagram of a neutral piece of plastic and a neutral area of skin on a person's hand.After the person runs the plasic between their fingers, some of the elctrons are transferred to the plastic, giving it a negative charge, and giving the skin a positive charge. A diagram of a neutral piece of plastic and a neutral area of skin on a person's hand.
  • When the plastic strip is rubbed on the skin, electrons from the skin are transferred to the plastic giving the plastic a negative charge.
  • When the plastic is moved near the desk, electrons in the desk are repelled by the negatively charged plastic.
  • This leaves an area of positive charge in the desk near the plastic.
  • The negative plastic and the positive area of the desk attract.

Balloon and Water

This video shows how a charged balloon can cause a stream of water to bend towards it when it is placed close to it.

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  • When the balloon is rubbed on hair or clothes, electrons move onto the balloon giving it a negative charge.
  • When the negatively charged balloon is brought near the water, electrons are repelled and move away from the balloon, leaving a positive area of the water near the balloon.
  • The negatively charged balloon and the positive area of the water attract.