Warm Up #18 How do direct and alternating current differ?

Lesson 3: Making an Electric Current with Magnets Ch. 10 Magnetism Lesson 3: Making an Electric Current with Magnets

Essential Questions How can a wire and a magnet produce an electric current? How do electric generators create an electric current? How are transformers used to bring an electric current into your home?

Why does the Pendulum Slow Down? ACTIVITY Using a thread, suspend a strong magnet from a ring stand about0.5 cm off the table Pull the pendulum back 5 cm and gently release Count the swings until the pendulum stops Take a 3cm wide strip of foil and place on table so magnet doesn’t touch it Repeat step 2 and 3.

Generating Electric Current A magnet is moved through a wire coil that’s part of a closed electric circuit As magnetic field moves over the wire coil, an electric current is produced in the circuit When magnet stops moving there’s no current Direction of the current depends on the direction in which the magnet moves.

Simple Electric Generator Electric generator – a device that uses a magnetic field to transform mechanical energy to electric energy A crank rotates a wire coil through the magnetic field of a small permanent magnet, which produces an electric current in the circuit Current continues as the crank continues to rotate the coil within the magnetic field

Direct Current and Alternating Current Direct current – an electric current that flows in 1 direction Alternating current – an electric current that changes direction in a regular pattern

Generators and Power Plants Turbine – a shaft with a set of blades that spins when a stream of pressurized fluid strikes the blades Connected to a generator to supply mechanical energy

Transformers – Changing Voltage Transformer – a device that changes the voltage of an alternating current Has 2 wire coils wrapped around a single iron core Alternating current in primary coil produces a continually reversing magnetic field, which produces alternating current in the secondary coil

Electric Energy – From Power Plant to Your Home BrainPop – Electromagnetic Induction