What do you already know about electricity?
|
1. Here is a picture of an electrical wire. The wire is copper and the green outside is rubber. |
Congratulations! You have completed this section. |
1
|
In this activity, you will measure what happens when batteries are added together in a series. |
Engage
|
2
|
Explore
|
4
|
|
|
Now line up the two batteries, pointed the same way, with plus (+) to the right. Use something to keep them in line, such as the slot below a chalk board, the groove in a ruler, or the V in a folded piece of cardboard. |
Measure the total voltage from one end to the other and record
it below next to "measured: #1 plus #2".
|
|
6
|
Now get together with another team. Line up four batteries, all pointed the same way, with the (+) to the right. Make sure the ends are touching. Use something to keep them in line, such as the slot below a chalk board, the groove in a ruler, or the V in a folded piece of cardboard. |
7
|
Measure the total voltage from one end to the other and record
it below.
Take a snapshot of your graph. |
|
Explain
|
8
|
11
|
Elaborate
|
13
|
|
What is the voltage of combinations of batteries?
|
1
|
Electricity is a part of modern life. Almost everyone has electricity in their house and uses it in dozens of ways all day long. But most people don't know what electricity is or how it works! This unit will help you explore electricity. |
Exploring the question
|
2
|
You have completed the introduction. Click on the UDL HOME button below.
What is electricity?
|
1
|
Read the story of "Eduardo and Maria Make a Telegraph" by using the forward and back arrows below. |
Chapter 1
|
2
|
Chapter 2
|
3
|
4
|
5
|
Chapter 3
|
6
|
7
|
Chapter 4
|
8
|
9
|
10
|
Chapter 5
|
11
|
12
|
Chapter 6
|
13
|
14
|
15
|
"You're not," said her mother. "I've written it all out for
you on this piece of paper. There are two copies: one for you
and one for Eduardo. After a while you'll both know the code
by heart, but at first you'll use your tables to remember it.
Here's what the Morse code looks like. Remember, the dots
stand for short pulses of light and the dashes stand for long
ones." She handed a piece of paper to Maria. This is what it
looked like:
"I get it!" said Maria. "Eduardo, I'm sending you a message!" "Wait a minute!" said her mother. "I've got to give him his copy of the code." She went into Eduardo's room, gave him the other piece of paper with the Morse Code on it, and came out again." |
|
"Here goes!" said Maria.
She sent this message: .... Â .. Â . Â _.. Â .._ Â ._ Â ._. Â _.. Â _ _ _ Â ._._._ Â .... Â _ _ _ Â ._ _ Â ._ Â ._. Â . Â _._ _ Â _ _ _ Â .._ Â .._ Â _..
Click
here
if you want to print a copy of the Morse code.
|
Telegraph Story
|
1
|
In this activity you will test materials that conduct or insulate against the flow of electricity. |
Explore
|
2
|
|
|
|
Now you will build a real circuit tester. It can measure which
materials are conductors and which materials are insulators.
Use this drawing to build your circuit tester. Work in teams. Hold the wires against the ends of the AA or AAA battery and the test material (e.g., penny, plastic spoon, rubber band, eraser, pencil lead, paper clip, wood) with your fingers. |
What can conduct electricity?
|
1
|
In this activity, you will build a model of how electrical charges travel in a circuit and move energy from one place to another. |
Engage
|
2
|
You can model this process with a circle of students. Form a circle with everyone linking arms, including the teacher. Pretend that the teacher is the battery and a student across the circle is the light bulb. |
3
|
Explore
|
5
|
Make a "necklace" by putting a piece of string through four bendable straws, as in the picture. |
6
|
Tie the string into a loop, leaving about 30 cm of string that
is not inside the straws. Use a "square knot" as shown.
Trim the knot so that it will slide through the straws. |
Tape the necklace to a piece of cardboard in a rough rectangle. Leave the string a little loose. Leave two areas where the string is not inside the straws. |
7
|
Draw a picture of a battery on a piece of paper and tape it to the cardboard. Draw a picture of a light bulb and tape it to the cardboard. |
|
8
|
9
|
Explain
|
10
|
Here is a picture of an electric circuit showing charges
moving along the wires. Of course, real electrons are
very,
very, very small!
We can't see them.
|
11
|
12
|
String circuit | Electric circuit |
Straw | Wire |
Dots on the string | Electric charges in the wire |
Must make a loop for the string to move | Must make a complete circuit for the electricity to flow |
Cut the string –- no loop! | Open the switch –- no circuit! |
Pull the string to make dots move | Battery pushes and pulls charges |
Pinch the string, making resistance | Resist the flow of electric charges (electrical resistance) |
It takes energy to pull the string if it is pinched | It takes energy to make the electric charges flow when there's resistance, as in a light bulb or a motor |
When you move the string in one place, all the dots move at once | When you hook up the circuit, the charges in the wire all move at once |
Elaborate
|
13
|
String circuit | Electric circuit |
String moves through the straw | The wire does NOT move -- just the electric charges move |
Dots move slowly | Charges move very fast |
You can see the dots | Electric charges are too small to see |
14
|
How does electricity move through a wire?
|
1
|
In this activity, you will build a circuit to light a bulb with a battery, first with a model and then with a real bulb. |
Engage
|
2
|
Find a battery to look at. Draw a picture of the battery. Show
how the two ends of the battery are different.
Take a snapshot of your drawing. |
|
4
|
Explore
|
To work, electric devices need a circuit, which is a loop that
allows the current to flow in an unbroken path.
Here is a model of a circuit. You can open and close the switch by dragging the handle with your mouse. |
|
|
|
5
|
|
|
Explain
|
6
|
1. Draw a picture of your circuit that successfully lights a
bulb. You can use the battery and bulb stamps if you wish
below the
A
tool button on the draw tool. When your
drawing is complete, draw a red line in a loop to show the
path of the electric circuit.
Take a snapshot of your drawing. |
|
Elaborate
|
9
|
Now make a model circuit with more things in it: two batteries
and two bulbs. Into the blue space, drag two batteries, two
bulbs, and as many wires as you need to make a circuit. Make a
continuous loop with battery, bulb, and wires so that the
electricity will flow through all of them.
If you didn't succeed, try again! Make a loop so that the electricity can flow all the way around. Take a snapshot of your working circuit. |
|
How do you use batteries to light up a bulb?
|
1
|
In this activity you will examine a light bulb and make it glow using a hand generator. |
Engage
|
2
|
Here is a picture of a light bulb. When electric charges are
pushed through the bulb, a special wire called a filament
heats up. It gets so hot that it gives off light.
Draw a circle around the filament and label it "filament," using the drawing tool. Take a sanpshot of your drawing. |
Here is a picture of a hand-cranked electric generator. It is called a Genecon. When you turn the crank, it makes enough electricity to light up a holiday light. |
4
|
|
Explore
|
5
|
Connect a holiday light to the Genecon hand generator. |
6
|
Notice that the filament is connected to a tiny wire at each
end. Each wire is connected to the bigger wire that you
attached to the Genecon. This is how the electricity gets to
the filament from the Genecon.
Draw a picture of the holiday light, showing the filament and the two wires that connect to the circuit. Take a snapshot of your drawing. It will be saved in your lab book. |
7
|
Connect a holiday light to the Genecon. This time, also
connect the
voltage
sensor.
Click on the magnifying glass
for
a technical hint.
The voltage is a measure of how hard the electric charges are being pushed through the circuit. |
8
|
|
|
9
|
Make a prediction of what the voltage graph will look like if
you do the following. You can draw on the graph using the
pencil tool.
|
|
10
|
Now test your prediction.
|
Explain
|
11
|
|
|
Elaborate
|
12
|
|
|
13
|
14
|
Draw a picture of the circuit that you made with the Genecon,
the two holiday lights and the voltage sensor. You can use the
stamp tools on the right.
Take a snapshot of your drawing. |
15
|
How do light bulbs work?
|
What is electricity?
|
1
|
Now it's time to review and summarize what you have learned
about electricity. To help, you can show all of your snapshots
and some of your written answers from the activities. They are
all in your lab book.
Review the questions on the following pages. There is a separate page for each activity that you worked on. Be prepared to share your answers with the rest of the class. |
Story
|
2
|
Light a bulb!
|
6
|
Volts and lights
|
4
|
String circuit
|
5
|
Summary
|
8
|
9
|
Password: |
Wrapping up
|
1. Here is a picture of an electrical wire. The wire is copper and the green outside is rubber. |
4
|
5
|
What have you learned about electricity?
|