Presentation on theme: "Energy Transformations. Magnetic Field- a region of space near a magnet, electric current, or moving charged particle in which a magnetic force acts on."— Presentation transcript:
Magnetic Field- a region of space near a magnet, electric current, or moving charged particle in which a magnetic force acts on any other magnet, electric current, or moving charged particle. Insulator-A material that blocks the flow of electric current across it. Energy- The ability to do work Work- applying a force to an object over a distance, and (2) the object moves in response to the force. Newtons-SI units used to measure force.
2.Stored energy is chemical energy. 3.Heat outside is generated by solar energy. 4.If the particles in an object slow down, that means the temperature is cool or cold. 5.Form of energy in a battery is chemical energy. 6.How do I tell which car has the most kinetic energy? The one that is moving the fastest.
7.What is the energy transformation when a stretched rubber band is released? Potential energy transformed to kinetic energy. 8.What does the Law of Conservation of energy sat is true of all energy transformations? That energy is never created or destroyed and the sum of all the energies is constant.
9.When you move your leg, your body changes chemical energy supplied by food into mechanical kinetic energy. 10. When wood burns, chemical energy stored in the wood is changed into heat energy, and light energy. 11. Water flowing over a water fall is a good example of kinetic energy.
12.Describe the energy transformation in an electric motor. Chemical energy transforms to electrical energy to mechanical energy. 13. If you wrap an electrical wire around an iron core, you create a electromagnet 14. An electric motor transforms electrical energy into mechanical energy. 15. How do you increase the strength of an electromagnet? Increase the number of times you wrap the wire around the iron core
16.What does a generator do? Converts mechanical energy to electrical energy. 17. What energy transformations occur when a hair dryer is plugged into the outlet? Electrical energy is converted to heat energy. 18. Describe the energy transformations in an electric fan. Electric energy to kinetic energy.
19. Energy Transformations a.Light bulb is electrical to light energy and heat energy. b.Door bell is electrical to sound energy. c.Stove is electrical to heat energy. d.Fan is electrical to mechanical
20. Describe the way heat moves. Heat moves in three ways: Radiation, conduction, and convection. Radiation happens when heat moves as energy waves, called infrared waves, directly from its source to something else. Conduction is another way that heat moves through contact. Convection happens when a substance that can flow, like water or air is heated.
21.Infrared heat lamps are used at fast food restaurants to keep food hot. How is heat transferred to the food? Radiation. 22.The water at the top of a pot of water gets hot by convection. 23.A cool metal spoon gets hot while sitting in your moms coffee. How does this happen? By conduction.
23. Explain how a metal spoon gets hotter than a plastic spoon. Metal is a better conductor of heat than plastic. Plastic is an insulator. 24. Same as above. 25. True or false? A student lifting her books off the table is an example of work. True.
26.What instrument can be used to measure force? Spring scale. 27. How do simple machines make work easier for you? Simple machines reduce the amount of force needed to do the work. 28. How can you adjust a lever to lift a heavy box? Move the fulcrum closer to the load. 29. How can you adjust a ramp to push a heavy object up the ramp? Make the ramp longer.
30.How do you adjust a pulley system to require the least amount of effort to lift a weight? Add more pulleys. Or add a moveable pulley. 31. What simple machine is found in raising blinds, lifting a car with a construction crane, and using a block and tackle? Pulley 32.Which of the following is not considered a simple machine?
33.A pair of scissors is made of wedge and lever. 34.A door knob is made of which simple machine? Wheel and axle 35.Of the following, which is an example of a complex machine? Can opener.
Focus Question: How can you make a magnet that turns on and off? Challenge: Can you make a steel bolt into a magnet that will turn on and off? Test the rivet for magnetism by trying to move the washers. Materials 1 steel bolt 1 electromagnet wire (very long wire) 3 wires 1 compass 1 battery 1 switch 1 cup of paper clips Electromagnets – Activity 3.3
Share with the class: How did your group make a magnet that could turn off and on?
You need to know… An electromagnet is a piece of iron or steel with insulated wire wrapped around it. While electric current is flowing through the wire, the iron or steel becomes a temporary magnet.
1.What caused the electromagnet to become magnetic? 2.What happens when the switch is opened? 3.What happens when the battery is reversed or the wire connections are reversed? Electromagnets – Activity 3.3
You need to know… To make an electromagnet stronger, you could Increase the number of coils of insulated wire around the iron core Or Use more batteries or a battery with greater voltage in the electric circuit Or Increase the diameter of the core (use a thicker nail or rivet!)
Electromagnets Electromagnets: Using Electricity and Magnets Together A Segment of: A First Look: Magnets (1:42)A First Look: Magnets
Motors An electromagnet is a very important part of a motor. A motor changes electric energy to mechanical energy!
Focus Question: How does an electric motor transform electric energy to mechanical energy? Follow the first and second student procedures outlined on page 43 of your Team Handbook Explore Electric Motors Activity 3.4
Click on picture above for link with animations of a motor An electric motor contains an electromagnet that rotates between the poles of a permanent magnet. The coil of the electromagnet is connected to a battery or other source of electric current. When the current from the battery flows through the wire in the electromagnet it produces a magnetic field and becomes a magnet. Like poles of the magnets repel and unlike poles of the magnets attract. This causes the coil to rotate and thus changes electrical energy to mechanical energy! electromagnet Permanent magnet battery
What are electric motors? An electric motor is a device which changes electrical energy into mechanical energy.
Go to the next slide How does an electric motor work?
We have seen how electricity can produce a magnetic field, but a magnetic field can also produce electricity! Moving a loop of wire through a magnetic field produces an electric current. A generator is used to convert mechanical energy into electrical energy.