Open and Closed Circuits

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Open and Closed Circuits
Science Electricity: Lesson 9: Open and Closed Circuits and Switches Materials needed: -yellow and black unifix cube (or piece of paper) for each student -open, closed circuit, switch sheets for each student -box for each pair of students: -1 battery in holder -1 bulb in holder -3 wires -baggie for each pair of students: -2 paper fasteners -index card with two holes -large paper clip -2 fahnestock clips 1

How is current electricity produced?
The BIG Question: How is current electricity produced? Last time, we answered this big question. We have learned four important conclusions about how current electricity is produced. Turn and talk to your partner. See if you can name all 4.

something must touch the positive and negative terminal of the battery
something must touch the threaded base and the tip of the bulb What conclusion did we make about the battery? * What conclusion did we make about the bulb? * What conclusion did we make about the direction current electricity flows? * What conclusion are we missing? * I am going to show you some pictures. You need to decided if the bulb will light or not light. I am giving you two cubes – yellow and black. Lay them inside your pencil tray so only you can see each one. current electricity can only flow from negative to positive electricity needs a complete circle in order to flow + + + +

NO! Will the bulb light? + Take a close look at this arrangement.
Decide if the bulb will light or not. If you think it will light, you are going to hold up the yellow cube. If you think it will not light, you are going to hold up the black cube. Put your choice on your finger inside your desk. Hold up your choice! The correct answer is…* + NO!

YES! Will the bulb light? + Take a close look at this arrangement.

YES! Will the bulb light? + Take a close look at this arrangement.

NO! Will the bulb light? + Take a close look at this arrangement.

YES! Will the bulb light? + + Take a close look at this arrangement.
Decide if the bulb will light or not. Put your choice on your finger inside your desk. Hold up your choice! The correct answer is…* + + YES!

NO! Will the bulb light? + + Take a close look at this arrangement.
Decide if the bulb will light or not. Put your choice on your finger inside your desk. Hold up your choice! The correct answer is…* NO! + +

NO! Will the bulb light? + Take a close look at this arrangement.

YES! Will the bulb light? + Take a close look at this arrangement.
Decide if the bulb will light or not. Put your choice on your finger inside your desk. Hold up your choice! The correct answer is…* Today we have a new big question… YES! +

How can I control the electricity flowing through a circuit?
The BIG Question: How can I control the electricity flowing through a circuit? Would someone like to read it? To answer our question, we first need to build a circuit. For our circuit, we are going to use 4 components…

components: First, to give our electrons a push, we’ll use * one battery, and to make it easier for us to connect our components, we’ll put our battery in the battery holder. Next we’ll use * two wires for our electrons to travel through. We’ll use one bulb, but today we’ll also put our bulb in a * holder. Then we won’t need to use our hands to hold our circuit together. Let’s get our supplies to build our circuits. When you get your box, take out these 4 components. Take a close look at your bulb holder. Where does one of the clips lead? Where does the other clip lead?

Inside a Light Bulb filament
We know that something must touch the threaded base * and the tip * of the bulb so electricity has a complete path * through the light bulb. What do you call that * thin wire inside the light bulb that glows when electricity pushes through it? * Now we’re ready to build our circuit.

Using a fahnestock clip
Your bulb holder has fahnestock clips just like your battery holder. Let me just remind you how to use those clips. First * you use your thumb to press down on the part that sticks up. When you do that, a hole will pop up in the middle. You need to * put the end of the wire all the way through this hole and then let go of the clip. Remember, though, not to put any of the black part of the wire through the hole. When you let go, * the wire will be held in place in the hole.

components: Go ahead and build a circuit using your four components. (give students time to build circuits) I am going to give you a piece of paper where we can draw a picture of our circuit. Please write a 20 on the front in the bottom right corner and a 21 on the back in the bottom left corner.

How can I control the electricity flowing through a circuit?
closed circuit How can I control the electricity flowing through a circuit? We’ll use the top half of our sheet to draw a picture of our circuit. I would like you to use only the left side. First let’s draw our battery *. Be sure to label the positive and negative terminal. Now let’s draw * our light bulb. Be sure we can see the threaded base and the tip. Finally, let’s add our wires. One must connect to the * tip of our bulb, and the other must connect to the * threaded base. Let’s draw some lines around our bulb * to show that it is lit. The circuit we just built has a name. It is called a * closed circuit. Turn and talk to your partner. See if you can come up with a definition for a closed circuit. (share)

a complete circuit that allows electricity to flow
closed circuit a complete circuit that allows electricity to flow ______________________________________________ _____________________________________________ Let’s add the definition of closed circuit to the bottom of sheet. We’ll write the words * closed circuit in the box. On the lines we’ll write our definition. *

How can I control the electricity flowing through a circuit?
closed circuit How can I control the electricity flowing through a circuit? O L S C E Now let’s go back to the top and add another picture to help us remember what a closed circuit is. Let’s use the letters in the words * closed circuit to make a complete circle. We’ll add * arrows to show that the electricity can flow. Now I want you to disconnect one wire somewhere in your circuit. What happens? (the bulb goes out) Flip your paper over on the back. T D I C U I C R

How can I control the electricity flowing through a circuit?
open circuit How can I control the electricity flowing through a circuit? Draw a picture of your circuit now. * Your picture may be different than mine depending on where you disconnected your wire. I disconnected mine from the positive terminal of my battery. You might have disconnected yours from the negative terminal or from the threaded base or tip of the light bulb. The circuit we have now also has a name. The first circuit we built was a closed circuit. What do you think this circuit might be called? * Turn and talk to your partner. See if you can come up with a definition for an open circuit. (share)

an incomplete circuit that does not allow electricity to flow
open circuit an incomplete circuit that does not allow electricity to flow ______________________________________________ _____________________________________________ Let’s add the definition of open circuit to the bottom of sheet. We’ll write the words * open circuit in the box. On the lines we’ll write our definition. *

How can I control the electricity flowing through a circuit?
open circuit How can I control the electricity flowing through a circuit? O P Now let’s go back to the top and add another picture to help us remember what an open circuit is. Let’s use the letters in the words * open circuit to make an incomplete circle. Look around the room. Let’s see if we can find some open and closed circuits. How about the lights? Is the circuit open or closed? (open if off, closed if on) The projector? (closed) The TV? (open) The heater? (closed) The laptop? (closed) The radio? (open) E T N I C U I C R

The filament is broken. The circuit is open and no electrons can flow.
The circuit is closed. Electrons flow through the filament and produce light. We have been using a light bulb as an important component of our circuits. In this light bulb, the circuit is closed and electrons flow through the filament to produce light. When a light bulb burns out, like * this light bulb, that will create an open circuit. The filament is broken, so the circuit is open and no electrons can flow. Add this sheet to your Electricity Notebook. Let’s go back to our big question for a minute… The filament is broken. The circuit is open and no electrons can flow.

How can I control the electricity flowing through a circuit?
The BIG Question: How can I control the electricity flowing through a circuit? We controlled the electricity flowing through our circuit by disconnecting a wire. But, if I wanted to control the electricity flowing through our classroom lights, I don’t have to disconnect any wires. If I want to turn on my TV, I don’t have to reconnect some wires. What device do I use to open or close these circuits? (switch)

A switch can be used to open and close a circuit.
So a switch is a device that can let you quickly and safely control the electricity flowing through a circuit. You can easily change from a closed circuit that lets electricity flow to an open circuit that does not allow electricity to flow. Today, I am going to challenge you to build a switch for your circuit.

components: . . I am going to give you some additional components to use. First you will need another wire * from your box. I am also giving you a baggie with the following components: * A piece of paper with two holes in it * A paper clip * Two paper fasteners You can build your switch with just these components. However, I am also giving you * two fahnestock clips. You can use these to attach your wires more easily if you wish. So here are your things to do…

Things to do: Build a switch that will allow you to easily

a device that can be used to open and close a circuit
switch a device that can be used to open and close a circuit ______________________________________________ _____________________________________________ Let’s add the definition of switch to the bottom of our sheet. We’ll write the word * switch in the box. Does anyone remember what we said the definition was? We’ll write that on the lines. *

Inside a Switch Closed Circuit Open Circuit
There are many different types of switches. The most common type of switch for lights looks like this. When the switch is in the closed position, like it is now, electricity has * a complete path and can flow. The light turns on. When the switch is in the open position, the path is broken and electricity cannot flow. The light turns off. Let’s add our sheet to our Electricity Notebook. Write a 22 on the bottom right corner of your sheet. Then add it to your Notebook.

Electrifying Vocabulary 1-2 My Prior Knowledge 3-4 All About Atoms 5
How is Static Electricity Produced? 6-8 How Electrical Charges Affect One Another 9-10 How is Current Electricity Produced? 11-16 We need to add an entry to our Table of Contents. Find your Table of Contents page. On the next line, we’ll write…* For the page numbers, we’ll write…* We also need to add some new words to our electrifying vocabulary pages. What do you call a complete circuit that allows electricity to flow? Will the Bulb Light? 17 Parts of a Light Bulb 18-19 Open and Closed Circuits 20-22

Electrifying Vocabulary
current electricity - pg. 12 circuit - pg. 15 closed circuit - pg. 20 Find the C box and add the words * closed circuit and the page number. What do you call an incomplete circuit that does not allow electricity to flow?

Electrifying Vocabulary
open circuit - pg. 21 Find the O box and add the words * open circuit and the page number. What do you call the device that allows you to open and close a circuit?

Electrifying Vocabulary
S static electricity - pg. 8 switch - pg. 22 Find the S box. Write the word * switch and the page number.