The Science of Electricity

1. The Science of Electricity By: Nicole Hayes

2. What is Electricity? • Electricity is a form of energy that starts with atoms.

3. All About Atoms • Atoms are tiny particles that make up everything around us. • Atoms have 3 basic parts: • Protons • Inside the nucleus. • + charged • Neutrons • Inside the nucleus • No charge • Electrons • In rings around the nucleus. • - charged • Atoms have the same number of protons and electrons.

4. Diagram of an Atom

5. Electron Movement • Electricity can be created by forcing electrons to flow from atom to atom.

6. The Periodic Table • A chart which organizes the elements. • Made by DimitriMendelev in 1869. • Atoms are arranged by increasing atomic number (number of protons in nucleus). • Vertical columns are called groups. • Horizontal rows are called periods. • Placement of element on table indicates ability to produce electricity.

8. Happy Atoms • Atoms are the happiest when their outer shell is full of electrons. (2-8-18-32) • Atoms will tend to bond with those who can make them “happy”. • Those who have fewer electrons will share them with another who has more. • This flowing of electrons by “donors” make them good conductors.

9. Conductors • Elements that allow electrons to flow easily through it. (Electricity flows). • Determined by number of valence (outer shell) electrons. • Conductors have 3 or fewer valence electrons.

10. Insulator • An element that does not allow electrons to move freely within it. • Elements with a full set of valence electrons.

11. Semi-Conductors • An element that is neither a conductor nor a good insulator. • Allows some current to flow, but offers a lot of resistance. • Found in transistors, integrated circuits, and solar cells. • Outer shell has exactly 4 electrons.

12. Current vs. Static Electricity • Electricity that is moving. • Ex: Copper wire moving electricity from a power plant to a house. • Electricity that is standing still. • Ex: Getting a shock after walking across carpet and touching something.

13. How is Electricity Produced • Various energy sources are used to turn turbines. • The spinning turbine shaft turns electromagnets which are surrounded by heavy coils of copper wire inside generators. • This creates a magnetic field which allows the electrons in copper wire to pass freely from one atom to another.

14. Turbines

15. Sending Electricity Out From the Plant • Electricity is sent down transmission lines from the plant. • Electricity loses some of its voltage (strength) as it travels. • Transformers help boost up its power. • When the electricity gets where it needs to go, the voltage must be stepped down before being used. This is done at sub-stations.

16. The electricity is then carried on distribution lines throughout neighborhoods to houses. • It is stepped down one more time before entering the house. • It enters the house through wires passing through a meter box. • When you flip a switch, you complete a circuit. • This allows electricity to pass through the appliance, back down the cord, and back into the electrical line.

18. Electrical Terms • Voltage- the “pressure” under which electricity flows. • Like turning on the faucet for the flow of water. • Amperage- measures the amount of electrical current. • Measuring the amount of water moving through the hose. • Watts- measures the amount of work done by a certain amount of current at a certain pressure. • Washing a muddy car off would require much more water at a higher pressure.

19. Formulas • _____P_____ I E Where P is power (watts), I is current (amps), E is voltage. • So, watts = amps x volts • Watts/current = voltage • Watts/voltage= current

20. Time to Explore • Click on the link below to explore electricity. • http://www.thetech.org/exhibits/online/topics/10a.html