Lesson 13 — Activity 3: Electrical Energy through Resistance
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Lesson 13 — Activity 3:
Electrical Energy
through Resistance
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In the last activity, you learned about electricity and circuits. In this activity, you will learn how resistance works to convert electric energy into other forms of energy.
Energy can exist in several forms. Voltage and current affect the conversion of electrical energy into other forms of energy.
Why
are some materials good conductors of electrical energy while others
are not? The difference is the resistance of the material to the
movement of charged particles. In other words, a material that has a high resistance will not let electrons move easily through it (low current). A material with
low resistance allows electrons to move through it quite easily (high current).
A good conductor lets currents flow through it — a good conductor is not very resistant. A good insulator, on the other hand, will be very resistant. The concept of resistance relates to the extent a material is a conductor. Take a look at the picture
below for some examples of good conductors and insulators.
Why
are some materials good conductors of electrical energy while others
are not? The difference is the resistance of the material to the
movement of charged particles. In other words, a material that has a high resistance will not let electrons move easily through it (low current). A material with
low resistance allows electrons to move through it quite easily (high current).
Resistance is important. When electrical current flows through a material with high resistance, the electrical energy is converted into a different form.
An everyday example of resistance at work is the light bulb. In an ordinary, round light bulb, tungsten is used to produce light (and heat). Tungsten is a highly resistant metal, so a current cannot move easily through the tungsten filament in a light bulb. As a result, the electrical energy in the filament is converted into light and heat.
Do you have a dimmer switch on some lights in your home? This is an example of resistance that you can control when you want dim or bright light. A dimmer switch controls the current and voltage. When the switch offers more resistance, the light is dim. When the resistance is less, the light is brighter because the electrical energy can flow through the wire to the bulb more freely.
Perhaps you can think of this as similar to a water hose. The valve can be turned fully open — with no resistance, the pail fills quickly! Turn the valve down — restrict the flow (give greater resistance), and the pail fills slowly.
An everyday example of resistance at work is the light bulb. In an ordinary, round light bulb, tungsten is used to produce light (and heat). Tungsten is a highly resistant metal, so a current cannot move easily through the tungsten filament in a light bulb. As a result, the electrical energy in the filament is converted into light and heat.
Do you have a dimmer switch on some lights in your home? This is an example of resistance that you can control when you want dim or bright light. A dimmer switch controls the current and voltage. When the switch offers more resistance, the light is dim. When the resistance is less, the light is brighter because the electrical energy can flow through the wire to the bulb more freely.
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