an activity to show transfer of charges using an electroscope
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Alright. Let's talk about electroscopes and methods that we can transfer charge. Alright. First off, we know that there is charge out there but we want to somehow be able to measure it. Well, how are we going to do that? Well, we're going to use something called an electroscope.
An electroscope is a piece of metal that consist of a knob, a long wire and then two very very very thin, usually gold foil, leaves. Okay? So these are all connected, they're all wire and that's going to mean that charge can flow freely through them. Alright. Now how does this work? Well, let's say that I bring a glass rod close to the knob of an electroscope, and this guy's been electrified. Alright? Well, what's going to happen is this positive charge, it really likes the negative charge. Remember that positives attract negatives. Now these positives can't go anywhere. So they're just kind of stuck. But the negative charges inside the conductor can all conspire to jump up to the knob. So if the negatives come up out of the leaves into the knob, then that leaves positives down here. So both of the leaves are positively charged. But just like pit balls, that means they're going to repel each other. So these guys are going to move apart. And that's how we're going to measure it. We're just going to look at the leaves and if they move apart, means we got some charge. Alright?
What about negative charge? Well, it's going to do the same thing. Look what happens. Negative right? Now, negative charge doesn't like other negative charge so the negative charge up in the knob instead of running up there is going to run down to the leaves. That's going to leave positives in the knob and negatives in the leaves. And again, they'll go apart. So using an uncharged electroscope, we're able to measure the existence of charge but we can't tell the difference between positive and negative. So it's very important to remember an uncharged electroscope can give you an idea that there is charge there but it can't tell you positive versus negative. Alright. So how can we do that? Well, let's see.
What if we charge the electroscope? So now, what if I start off with an electroscope that already has positive charge on it? So that means that these leaves are already a little bit apart. So now I'm going to bring a positively charged glass rod close to it. Well, again, that's going to attract electrons. It's going to attract negative charge. So I've got negative negative. And what does that leave behind? Well, it leaves more positives behind. So that means that these guys are going to move further apart. Okay. So that's the same thing that happened before. The uncharged electroscope. So what gives, what does that buy us? Well, what if I bring negative charge close?
Well, negative charge is going to scare the negatives down into the leaves and leave positives up in the knob. And notice what happens now. Now the leaves are less charged. So that means they're going to be drawn together, basically, by gravity. So these guys get closer together. And so now, with the charged electroscope, I can tell whether the rod that I'm bringing close to the knob has the same charge as the electroscope or the opposite charge. And that's very nice. It actually allows us to get an entire system going. Once we choose, the glass rods are positively charged, then we can just hold them up to electroscopes, hold anything that's electrified up, and just see what happens. And we can tell whether that thing is positively charged or negatively charged.
Alright. Now, how do we charge this electroscope in the first place? There's two major ways that we can charge an object that was initially uncharged. The first is conduction, and conduction is associated with taking something that's already charged and then touching it to something that's uncharged. Now, as I bring it closer, these positive charges are going to push all the positive charges over to the other side and the negative charges over there. So this is called polarized. I have polarized this material. Alright. So now when I let them touch, some of the negatives are going to jump over. And then I pull them apart and look what's left, he's positively charged. So that's charging by conduction. Charging by conduction is very very very simple. It gives you the same charge that you started off with and it involves direct contact between the two things
An electroscope is a piece of metal that consist of a knob, a long wire and then two very very very thin, usually gold foil, leaves. Okay? So these are all connected, they're all wire and that's going to mean that charge can flow freely through them. Alright. Now how does this work? Well, let's say that I bring a glass rod close to the knob of an electroscope, and this guy's been electrified. Alright? Well, what's going to happen is this positive charge, it really likes the negative charge. Remember that positives attract negatives. Now these positives can't go anywhere. So they're just kind of stuck. But the negative charges inside the conductor can all conspire to jump up to the knob. So if the negatives come up out of the leaves into the knob, then that leaves positives down here. So both of the leaves are positively charged. But just like pit balls, that means they're going to repel each other. So these guys are going to move apart. And that's how we're going to measure it. We're just going to look at the leaves and if they move apart, means we got some charge. Alright?
What about negative charge? Well, it's going to do the same thing. Look what happens. Negative right? Now, negative charge doesn't like other negative charge so the negative charge up in the knob instead of running up there is going to run down to the leaves. That's going to leave positives in the knob and negatives in the leaves. And again, they'll go apart. So using an uncharged electroscope, we're able to measure the existence of charge but we can't tell the difference between positive and negative. So it's very important to remember an uncharged electroscope can give you an idea that there is charge there but it can't tell you positive versus negative. Alright. So how can we do that? Well, let's see.
What if we charge the electroscope? So now, what if I start off with an electroscope that already has positive charge on it? So that means that these leaves are already a little bit apart. So now I'm going to bring a positively charged glass rod close to it. Well, again, that's going to attract electrons. It's going to attract negative charge. So I've got negative negative. And what does that leave behind? Well, it leaves more positives behind. So that means that these guys are going to move further apart. Okay. So that's the same thing that happened before. The uncharged electroscope. So what gives, what does that buy us? Well, what if I bring negative charge close?
Well, negative charge is going to scare the negatives down into the leaves and leave positives up in the knob. And notice what happens now. Now the leaves are less charged. So that means they're going to be drawn together, basically, by gravity. So these guys get closer together. And so now, with the charged electroscope, I can tell whether the rod that I'm bringing close to the knob has the same charge as the electroscope or the opposite charge. And that's very nice. It actually allows us to get an entire system going. Once we choose, the glass rods are positively charged, then we can just hold them up to electroscopes, hold anything that's electrified up, and just see what happens. And we can tell whether that thing is positively charged or negatively charged.
Alright. Now, how do we charge this electroscope in the first place? There's two major ways that we can charge an object that was initially uncharged. The first is conduction, and conduction is associated with taking something that's already charged and then touching it to something that's uncharged. Now, as I bring it closer, these positive charges are going to push all the positive charges over to the other side and the negative charges over there. So this is called polarized. I have polarized this material. Alright. So now when I let them touch, some of the negatives are going to jump over. And then I pull them apart and look what's left, he's positively charged. So that's charging by conduction. Charging by conduction is very very very simple. It gives you the same charge that you started off with and it involves direct contact between the two things
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hope it helps mark as brainliest plz
materials
Glass jar with lid
Awl
2'' of plastic straw
10'' of 14 gauge copper wire
Hot glue
Pliers
Balloon
Any other materials you'd like to test for a charge, such as carpet, rubber, or vinyl
2 - 2'' square pieces of aluminum foil (or gold leaf)
Steps
Safety Tip!! Get an adult to help you punch a hole in the lid.
1. Start by punching a hole in the jar lid large enough for the straw and copper wire to fit through.
2. Insert the straw into the hole and center it. Leave a couple inches of space from the bottom of the jar. Use the hot glue to secure the straw in place.
3. Next, insert the copper wire into the straw, with about 2'' protruding from the straw inside the jar.
4. Use the pliers to bend 1'' of the copper wire into a hook to hold the aluminum foil later.
5. Use the pliers to bend the remaining copper on top of the lid into a coil to provide more surface area.
6. Next, cut a small slit in the aluminum foil and slide them onto the copper hook.
7. Attach the lid to the jar.
Electroscope setup
setup
8. Now, rub the balloon on your hair.
9. Place the balloon next to the copper coils. Observe what happens to the metal inside the jar.
10. Move the material away and touch your hand to the coiled wire. Observe what happens.
11. Repeat step 8-10 with any other materials you would like to test.
Troubleshooting
Make sure you use the correct gauge wire. Thicker wire will conduct more electricity, thus producing a stronger result. Thinner wire, or fewer coils will not work as well. For the best results, make sure you thoroughly rub the balloon or other materials on your hair. They must accumulate a sufficient charge for the electroscope to detect it.
Discussion Questions
What happened when you put the charged material near the electroscope and why?
What happened when you touched the electroscope?
Why did we use aluminum foil or gold leaf inside the jar and not plastic?
How It Works
An electroscope detects electrical charge. When you rubbed the material on your hair, your hair transferred electrons to the material, giving it a negative charge. This process is called induction, or the process of accumulating charge.
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materials
Glass jar with lid
Awl
2'' of plastic straw
10'' of 14 gauge copper wire
Hot glue
Pliers
Balloon
Any other materials you'd like to test for a charge, such as carpet, rubber, or vinyl
2 - 2'' square pieces of aluminum foil (or gold leaf)
Steps
Safety Tip!! Get an adult to help you punch a hole in the lid.
1. Start by punching a hole in the jar lid large enough for the straw and copper wire to fit through.
2. Insert the straw into the hole and center it. Leave a couple inches of space from the bottom of the jar. Use the hot glue to secure the straw in place.
3. Next, insert the copper wire into the straw, with about 2'' protruding from the straw inside the jar.
4. Use the pliers to bend 1'' of the copper wire into a hook to hold the aluminum foil later.
5. Use the pliers to bend the remaining copper on top of the lid into a coil to provide more surface area.
6. Next, cut a small slit in the aluminum foil and slide them onto the copper hook.
7. Attach the lid to the jar.
Electroscope setup
setup
8. Now, rub the balloon on your hair.
9. Place the balloon next to the copper coils. Observe what happens to the metal inside the jar.
10. Move the material away and touch your hand to the coiled wire. Observe what happens.
11. Repeat step 8-10 with any other materials you would like to test.
Troubleshooting
Make sure you use the correct gauge wire. Thicker wire will conduct more electricity, thus producing a stronger result. Thinner wire, or fewer coils will not work as well. For the best results, make sure you thoroughly rub the balloon or other materials on your hair. They must accumulate a sufficient charge for the electroscope to detect it.
Discussion Questions
What happened when you put the charged material near the electroscope and why?
What happened when you touched the electroscope?
Why did we use aluminum foil or gold leaf inside the jar and not plastic?
How It Works
An electroscope detects electrical charge. When you rubbed the material on your hair, your hair transferred electrons to the material, giving it a negative charge. This process is called induction, or the process of accumulating charge.
To unlock this lesson you must be a Study.com Member.
Create your account
Register to view this lesson
Are you a student or a teacher?
Electroscope Experiment Related Study Materials
Related
Recently Updated
Popular
Explore Subjects
Create an account to start this course today
Try it risk-free for 30 days!
Like this lesson Share
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Search
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