You can use the idea that like charges repel (like two electrons) and opposites attract to move stuff around, stick to walls, float, spin, and roll. Make sure you do this experiment first.
I’ve got two different videos that use positive and negative charges to make things rotate, the first of which is more of a demonstration (unless you happen to have a 50,000 Volt electrostatic generator on hand), and the second is a homemade version on a smaller scale.
Did you know that you can make a motor turn using static electricity? Here’s how:
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Download Student Worksheet & Exercises
Here’s how the electrostatic machine works – you will need:
- a yardstick
- spoon
- balloon
How does it work? Different parts of the atom have different electrical charges. The proton has a positive charge, the neutron has no charge (neutron, neutral get it?) and the electron has a negative charge. These charges repel and attract one another kind of like magnets repel or attract. Like charges repel (push away) one another and unlike charges attract one another.
So if two items that are both negatively charged get close to one another, the two items will try to get away from one another. If two items are both positively charged, they will try to get away from one another. If one item is positive and the other negative, they will try to come together.
How do things get charged? Generally things are neutrally charged. They aren’t very positive or negative. However, occasionally (or on purpose as we’ll see later) things can gain a charge. Things get charged when electrons move. Electrons are negatively charged particles. So if an object has more electrons than it usually does, that object would have a negative charge. If an object has less electrons than protons (positive charges), it would have a positive charge.
How do electrons move? It turns out that electrons can be kind of loosey-goosey. Depending on the type of atom they are a part of, they are quite willing to jump ship and go somewhere else. The way to get them to jump ship is to rub things together.
Remember, in static electricity, electrons are negatively charged and they can move from one object to another. This movement of electrons can create a positive charge (if something has too few electrons) or a negative charge (if something has too many electrons). It turns out that electrons will also move around inside an object without necessarily leaving the object. When this happens the object is said to have a temporary charge.
Try this: Blow up a balloon. When you rub the balloon on your head, the balloon is now filled up with extra electrons, and now has a negative charge. Now stick it to a wall— to create a temporary charge on a wall.
Opposite charges attract right? So, is the entire wall now an opposite charge from the balloon? No. In fact, the wall is not charged at all. It is neutral. So why did the balloon stick to it?
The balloon is negatively charged. It created a temporary positive charge when it got close to the wall. As the balloon gets closer to the wall, it repels the electrons in the wall. The negatively charged electrons in the wall are repelled from the negatively charged electrons in the balloon.
Since the electrons are repelled, what is left behind? Positive charges. The section of wall that has had its electrons repelled is now left positively charged. The negatively charged balloon will now “stick” to the positively charged wall. The wall is temporarily charged because once you move the balloon away, the electrons will go back to where they were and there will no longer be a charge on that part of the wall.
This is why plastic wrap, Styrofoam packing popcorn, and socks right out of the dryer stick to things. All those things have charges and can create temporary charges on things they get close to.
Want to purchase an electrostatic machine? Here’s a link to the one used in the video called a Wimshurst Machine which makes sparks up to 4″ long. For younger kids, we recommend this fun hand-held, non-shocking electrostatic generator.
Exercises
- What happens if you rub the balloon on other things, like a wool sweater?
- If you position other people with charged balloons around the table, how long can you keep the yardstick going
- Can we see electrons?
- How do you get rid of extra electrons?
- Why do you think the yardstick moved?
- What would happen if you use both a positively charged object and a negatively charged object to make the yardstick move?
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THAT IS OUT OF THIS WORLD!!!!!!!!!!!!!!!!!!!!!
That’s right – you can rub a balloon and stick it to the wall, but why does that work? The wall isn’t positively charged, is it? Nope… the wall is not charged at all. It’s electrically neutral. However, when you bring a negatively charged balloon near it, two important things happen: the negative charge on the balloon repels the negative charges in the wall, pushing them further away. At the same time, the positive charges in the wall are attracted to the balloon and move toward it. The result is that the balloon sticks to the wall, and you have just moved charges around in the wall without even realizing it. Polarization means that you separate the charges in an object. The wall became polarized when you brought the balloon close to it.
You can read more about it here in the advanced physics section if you have the upper level membership.
The experiment was cool.Why does static electricity stick to something even if the thing it is sticking to is not charged?
We used firefox at first and couldn’t get the video to start. After changing it to safari it worked! Thank you for your speedy response, really appreciate it.
The video works over here… what browser and version are you using? And what happens if you try a different computer?
The video still doesn’t work.
Oops… sorry about that. I’ve fixed it so you can try it now.
I can’t make the Wimshurst machine the link is closed 🙁 O:(
Here’s a cool video from a student (Colin) of the electrostatic experiment, but modified:
It’s really hard to build a Wimshurst machine that works well… I recommend purchasing one from a science supplier. I actually have this one and like it a lot – the sparks are big enough to use in a classroom on a dry day. I set this up in my classes for kids to shock themselves and they always have such a great time.
NOTE: If you have anyone in your house with a pacemaker or other condition (this includes all pregnant women and babies), DO NOT use one of these machines – it produces enough of a jolt to adversely affect their heart. For healthy people, the volts and amps are way below the hazard threshold.
How do we build the advanced electrostatic machine? Do you have instructions on the website?
Yes, that can happen in higher-humidity locations. Maybe in the wintertime? 🙂
we tried but it did work. I think it is too humid where we live to do this… have to wait until we turn the heater on inside…
Whoops! Sorry about that… we recently moved things around in the background, and looks like we missed updating this link. Thanks for your eagle eye! All fixed now.
“You can use the idea that like charges repel (like two electrons) and opposites attract to move stuff around, stick to walls, float, spin, and roll. Make sure you do this experiment first.”
The link to the experiment mention above (under Advanced Static Electricity Experiments) is not working.