How can we change circuits to control the amount of electricity that flows?

Targets

At the end of this Unit you should be able to answer the following questions 

1. What are electricity and magnetism, and how can they be used safely?

1.1 What is electricity?

1.2 What is magnetism, and how is it related to electricity?

1.3 What are the dangers of electricity, and how can it be used safely?

2. How can electricity be controlled and used?

2.1 How is the electricity we use daily measured and paid for?

2.2 Do all materials allow electricity to flow through them?

2.3 How can we understand, design, and control electrical pathways?

2.4 How can we change circuits to control the amount of electricity that flows?

3. How can we use electrical circuits to build devices?

3.1 How can electrical technology be used to build devices and solve problems?

targets
You have learned that electricity will not flow in an open circuit. When a light bulb burns out, electricity cannot flow through it. That means that anything else in the circuit with the light bulb will not work either. That would be very bad, for example, in a kitchen or on a street. If a bulb burns out, the refrigerator or all street lights might stop working!

Using a rope to climb a cliff is like using a series circuit. If the rope breaks, the climber will not be able to get to the top of the cliff. In a series circuit, if one bulb/electrical device burns out the others will not work.

Pixabay

     

Christmas lights have many bulbs.  What happens when one bulb burns out?  Does the whole string go dark or just the one bulb?  By wiring circuits in various ways, we can keep electricity flowing even when part of the circuit is broken.

Pixabay

Each item needs a reliable supply of electricity.  When there are multiple paths for electricity to flow, even if one bulb burns out, the other bulbs remain lit.

Digging Deeper


A Cool Use of Electricity

Lightbulbs and How They Have Improved


Light bulbs are a great way to use electricity.  Electrical energy is converted into light energy, as well as heat energy.  You may have noticed that two types of light bulbs are used in homes these days. The incandescent light bulb has been around for a long time. The long fluorescent tubes have been used more in offices than in homes, but the small light tube is newer and is used increasingly in homes because less electricity is used to produce light. That is a good thing because electricity costs money, and energy is required to make electricity.

Did you know both types of lights depend on electricity moving from place to place? In the old-style light bulb, electricity flows through a very thin wire that heats so much that it gets white hot. This hot wire glows bright enough to light a whole room. The new-style light tube (and the long fluorescent tube) works differently. Electricity flows through a small amount of mercury metal gas that is inside the tube. The electricity gives the gas lots of energy, which makes a white coating on the inside of the tube glow bright white.  The more efficient bulbs convert less electricity into heat and more into light.

  Video

Watch Light Bulbs – What's Inside? How does electricity make a light bulb glow?


How tungsten works in the incandescent light bulb 


Watch how other lightbulbs such as LED bulbs work.

  Health Connection



Mercury is a poisonous metal that is used in very small amounts in light tubes.
Lights tubes should not be thrown into the regular garbage; they should be taken to a local toxic roundup. If you break a light tube, you should leave the room immediately and air out the area for 15 minutes. You should wear gloves to pick up the pieces of glass and metal.

Visit the Health Canada "Safety of Compact Fluorescent Lamps" website for complete cleanup instructions for light tubes.