Electricity and Circuits.ppt
- 2. Electric Charges • Three particles that make up an atom: – Protons – Neutrons – Electrons
- 3. The Flow of Charges • Which subatomic particle can move from one object to another? – Electrons! • What does the addition of electrons do to the charge of an object? – The object will become NEGATIVELY charged. • What does the removal of electrons do to the charge of an object? – The object will become POSITIVELY charged. e- e- e- e- e-
- 4. How Charges Interact • When two objects with the SAME charge come into contact, they _____________. • When two objects with DIFFERENT charges come into contact, they _____________.
- 5. Electric Current • What is an electric current? – The continuous flow of electric charges through a material. • What is the unit of measurement for current? – amperes (A) or amps: the amount of charge flowing past a point in a certain amount of time. e-
- 6. Potential Difference • What’s potential energy (PE)? • On a roller coaster, where does the car have more potential energy? • Can the car move from an area of low PE to high PE without the help of a motor? • It’s the same for electric current! – The charges in a current are like the roller coaster cars. – The track is like the wires. – The motor that gets the cars to the top of the first hill is like the battery.
- 7. Potential Difference Cont. • So what is Potential Difference? – The difference in potential energy between two locations. • The difference between a rollercoaster and an electric current is that the potential difference is caused by the difference in electrical charges in two locations, not height.
- 8. Potential Difference Cont. • Electric charges will always flow from a region of ___________ potential energy to a region of ___________ potential energy. • When the charge reaches the positive terminal and enters the battery, it gains electric potential energy as it travels through the battery to the negative terminal. e-
- 9. Voltage • What is it? – Another term for potential difference. • What unit is used to measure voltage? – Volts (V) • So in a 9-volt battery, when an electric charge moves from the negative terminal, through the battery, to the positive terminal, how much potential energy does the charge gain? – 9 volts! e-
- 10. Basic Circuits • A circuit is a path through which electricity can flow. • Most circuits have three parts: – An energy source – One or more loads (run by electricity) – Conductors (wires) that connect the two Create a basic circuit. Use only a battery, two wires, and a bulb. Draw your circuit on your notes page.
- 11. Parts of a Circuit • Energy Source – A circuit needs an energy source to push a charge through the circuit. – Examples? • Load – a load is a device in a circuit that operates using electrical energy. – Examples? • Conductor – a conductor is a material that allows electrical energy to flow through it easily. – What makes a good conductor? – Examples?
- 12. Parts of a Circuit Cont. • Resistor – a resistor is an object added to a circuit that restricts the flow of electrical energy. – Resistors inhibit the flow of electric current by producing a voltage drop when current passes through them. They limit current and cause some electric energy to be given off as heat. – Examples? • Switch - a switch is a device that is used to control the flow of current through a circuit. – A switch works by separating (open) or bringing together (closed) two conductors attached to a circuit.
- 13. Circuit Switches • Add a switch to your circuit. See what happens when you open and close the switch. • On your notes, draw a circuit with an open switch and a closed switch. Indicate whether the light is on or off. • When an electric current reaches an open switch, the current _________. – This creates an __________ circuit. • When an electric current reaches a closed switch, the current _________. – This creates a __________ circuit. • Why would you want a switch in a circuit?
- 14. Types of Circuits • Two types of circuits: – Series Circuit • Provides only one possible path for the flow of current. – Parallel Circuit • Offers more than one path for the flow of electricity.
- 15. Series Circuits • In a series circuit, the loads are set up in a series, or line, that requires the current to flow through one load before passing through the next. • Draw your circuit on your notes sheet. • Use arrows to indicate the direction the electric current is traveling.
- 16. Parallel Circuits • In a parallel circuit, each load has its own path for electricity. • Draw your circuit on your notes sheet. • Use arrows to indicate the directions the electric current is traveling.