We've just learned that electrons move through circuits flowing from a negative source to a
positive one. Today we are going to create our own circuit and then use it to perform
some experiments. Here are the supplies that we'll need: uncoated copper wire, E10 flashlight
bulbs and bulb holders, a Phillips screwdriver, electrical tape, and two double A batteries.
We'll first take one of the light bulbs and screw it into a bolt holder using the screwdriver. Go
ahead and loosen these screws. Okay, now I'm going to wrap a piece of copper wire around each screw.
Good. Now I'm going to re-tighten the screws like this.
Okay. Let's tape these wires to the positive and negative terminals of one of the batteries.
Once each wire is connected properly, the light receives electricity and lights up. See?
We did it! We created a complete circuit. This is called a series circuit because the flow of
electricity only flows in one direction and is not split. Okay. Let's see what else we
can discover about electricity using this circuit we've made! Let's try making the circuit bigger
by adding another light bulb. What do you think will happen? Open your student journal
to lesson 10 and write down your prediction in the first box. Pause the video if needed.
Now I'm going to detach one wire from our completed circuit and attach it
to this bolt holder and re-tighten the screw.
Now we need another piece of the copper wire, and we'll attach it to the other screw
and then tighten that screw back down. Good! Now let's tape the end of this wire to the remaining
battery terminal. Ta-da! Both light bulbs are lit, but what do you notice? Do you see that
the light bulbs are not as bright as the one light bulb was? Why do you think that happened?
There is the same amount of electricity, but now it is being used to light up both light bulbs,
so the brightness is affected. This is also a series circuit because the energy is still
flowing in one direction. Take a moment and write down the results in your student journal now.
Okay! Let's see what happens when we unscrew one of the light bulbs in this circuit.
As you can see, the circuit is broken and the flow of energy to both light bulbs stops.
Now let's try another experiment with our circuit. What do you think will happen if we
add another battery? Pause the video and write down your prediction in your student journal.
First, let's disconnect one of the wires from the battery and add the other battery by touching the
positive end of this battery to the negative end of this battery. Then, we'll re-secure the wire to
the new battery. Wow! What happened to our light? It's much brighter. This is because the power,
or voltage, is greater. The extra battery adds more voltage and this causes the electrons to move
faster, which makes the lights brighter. Go ahead and record these results in your student journal.
Now that we have two batteries connected, if we unscrew one light bulb what will happen?
The energy will not flow to either bulb because this is still a series circuit and the electricity
is still flowing in one direction. With one bulb disconnected, the energy flow is stopped.
Alright. Let's perform one more experiment! We're going to change things up a bit here.
I have a different type of circuit. I used one battery and two bulb holders.
I took the wire from one end and connected it to one side of the first light bulb.
Then I used another piece of wire and wrapped it around the same screw and connected it
to the screw of the other bulb holder. Now let's do the same thing on the other side.
We have light again, but we no longer have a series circuit. Do you know what this type of
circuit is called? It's a parallel circuit! The energy splits where the wires touch the screws and
each bulb has its own circuit. Now, what do you think will happen when we remove one light bulb?
Before we try, make your prediction in the third row in your student journal now.
Were your predictions correct? The other light bulb still has energy because in a
parallel circuit the bulbs receive individual power without running in one continuous line.
Great job today! Oh and don't forget to record these last results in your student journal now.