Presentation on theme: "ELECTRIC CIRCUITS ACTIVITY: BUILDING SIMPLE CIRCUITS Materials: circuit kit, power source Procedure: Using the materials provided.... 1) Create an electric."— Presentation transcript:
ELECTRIC CIRCUITS ACTIVITY: BUILDING SIMPLE CIRCUITS Materials: circuit kit, power source Procedure: Using the materials provided.... 1) Create an electric circuit that can light up one light bulb. Draw a picture of your circuit. 2) Create an electric circuit that can light up two light bulbs. Draw a picture of your circuit. 3) Create an electric circuit that has one light bulb that can be controlled by a switch. Draw a picture of your circuit. 4) Create an electric circuit that has two light bulbs and one of the light bulbs is controlled by a switch. Draw a picture of your circuit.
THE SIMPLE CIRCUIT There are four main parts found in a simple electric circuit. 1) Source of Electrical Energy - a device that converts one form of energy into electrical energy Batteries Generator Wall Outlet Photoelectric CellLemons??? An ELECTRIC CIRCUIT is a closed path along which electrons can flow continuously.
2) Connectors - conducting wires used to provide a controlled path for electric current 3) Electric Circuit Control Device - a switch that allows you to start and stop the flow of electricity 4) Electric Load - the device that converts electrical energy into whatever form of energy is needed (the load is the reason why the circuit was made in the first place.
CELLS AND BATTERIES Batteries (Dry Cells) + + + + positive terminal negative terminal positive electrode (ex. graphite) negative electrode (ex. zinc) electrolyte an electrolyte is any liquid that conducts an electric current a chemical reaction between the electrolyte and the negative electrode (zinc) causes electrons to collect there the chemical reaction between the electrolyte and the positive electrode (graphite) causes it to lose electrons
generally speaking, a CELL is any device that generates an electric current by chemical reactions involving two different metals and an electrolyte a battery is called a dry cell because it uses a paste as an electrolyte; when a liquid electrolyte is used the cell is called a wet cell. WET CELL
CELLS AND THE SIMPLE CIRCUIT + + + + electrons only flow when a circuit is complete or closed electrons leave the negative terminal and enter the positive terminal direct current is when electrons flow in one direction towards the positive terminal ELECTRIC CURRENT http://www.youtube.com/watch?v=5laTkjINHrg Electrons are so tiny that is would be hard to keep track of them individually. Scientists decided to group them into bundles called COULOMBS. The symbol for this is C. 1 C = 6.25 x 10 18 electrons = 6 250 000 000 000 000 000 electrons Think of 1 Coulomb as a package of electrons.
ELECTRIC CURRENT electrons flow through a complete circuit Electric current is the rate at which electric charges move past a given point in a circuit the symbol for current is I. Suppose we looked at point B in the circuit to the right and we observed 2 coulombs of charge move by in 2 seconds. The current would be: I = 2 C = 1 C/s = 1 amperes (or amps) 2 s the standard unit of measure for electric current is AMPERES. The symbol for amperes is A. 1 C/s = 1 A + + + + B
ELECTRICAL DEVICEELECTRIC CURRENT (amps) Electric wrist watch0.00013 Electric calculator0.002 Electric clock0.16 Light bulb (100 W)0.833 Television4.1 Electric drill4.5 Vacuum cleaner6.5 Stove element6.8 Oven element11.4 Toaster13.6 Water heater element 27.3 Car starter500 ELECTRIC CURRENT Maximum level of current considered safe Muscles convulse, breathing affected, human suffocates Severe burns; no breathing Muscles tingle 0.002 A 0.005 A 0.016 A 0.2 A