This is a recording of a recent live teleclass I did with thousands of kids from all over the world. I’ve included it here so you can participate and learn, too!
We’re going to study electrons and static charge. Kids will build simple electrostatic motor to help them understand how like charges repel and opposites attract. After you’ve completed this teleclass, be sure to hop on over the teleclass in Robotics!
Electrons are strange and unusual little fellows. Strange things happen when too many or too few of the little fellows get together. Some things may be attracted to other things or some things may push other things away. Occasionally you may see a spark of light and sound. The light and sound may be quite small or may be as large as a bolt of lightning. When electrons gather, strange things happen. Those strange things are static electricity.
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Materials:
- Balloon (7-9″, inflated with air, not helium)
- AA battery case
- 2 AA batteries for your battery case (cheap dollar-store “heavy duty” type are perfect. Don’t use alkaline batteries if you can help it, because kids are going to short circuit their circuits, and the cheaper kind are safer in case they do.)
- 1-2 LEDs
- Alligator wires
- 1.5-3V DC motor
- 3-6V buzzer
If you want to make the laser burglar alarm, then get these also:
- OPTIONAL: CdS Photoresistor for the laser burglar alarm
- OPTIONAL: 9V Battery for laser burglar alarm
- OPTIONAL: Laser pointer (the cheap kind from the dollar store work great) or strong flashlight for the laser burglar alarm
If you want to make the first robotics projects then also get these:
- OPTIONAL: block of foam (any kind will do that is at least 2″ on each side)
- OPTIONAL: 10 (or more) wood skewers at least 4″ long
- OPTIONAL: 1 wood clothespin
- OPTIONAL: Hot glue and glue sticks (with adult help)
If you want to make the second robotics project then also get these:
- OPTIONAL: Additional 3V DV motor (you need two for this project)
- OPTIONAL: 6 large popsicle sticks (tongue depressor size)
- OPTIONAL: Tack or other sharp object for poking holes
- OPTIONAL: Hot glue and glue sticks (with adult help)
Key Concepts
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. Generally things are neutrally charged. They aren’t very positive or negative, rather have a balance of both.
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. Like in our experiment we’re about to do…
What’s Going On?
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.
When you rub a balloon on your head, the balloon is now filled up with extra electrons, and now has a negative charge. Opposite charges attract right? So, is the entire yardstick now an opposite charge from the balloon? No. In fact, the yardstick is not charged at all. It is neutral. So why did the balloon attract it?
The balloon is negatively charged. It created a temporary positive charge when it got close to the yardstick. As the balloon gets closer to the yardstick, it repels the electrons in the yardstick. The negatively charged electrons in the yardstick are repelled from the negatively charged electrons in the balloon.
Since the electrons are repelled, what is left behind? Positive charges. The section of yardstick that has had its electrons repelled is now left positively charged. The negatively charged balloon will now be attracted to the positively charged yardstick. The yardstick 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 yardstick.
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.
Questions to Ask
- Does the shape of the balloon matter? Does hair color matter?
- 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, can you keep the yardstick going?
- Can we see electrons?
- How do you get rid of extra electrons?
- Rub a balloon on your head, and then lift it up about 5 inches. Why is the hair attracted to the balloon?
- Why does the hair continue to stand on end after the balloon is taken away?
- Why do you think the yardstick moved?
- What other things are attracted or repelled the same way by the balloon? (Hint: try a ping pong ball.)
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Yes, that can affect the jiggling. If you feel that your project isn’t working correctly, you can take nice, in-focus picture and email it to aurora@superchargedscience.com. Be sure to mention your concerns in the email.
Hey Aurora. I just realised that the motors on the popsicle sticks were facing up-right. Does this afect the jiggleing?
Thanks for explaining further. Are you asking if the experiments in the teleclass are found elsewhere on the website? If so, then the answer is yes. I also re-did the teleclass in greater depth and you can find it here: https://www.sciencelearningspace.com/science-with-aurora/november-electricity-magnetism
Sorry for the confusion. I am not looking for more experiments. I am just wondering if the experiments you did in your teleclass are the same as the other experiments in this Unit? I am not exactly sure how to explain what I mean. I have not watched your teleclass yet because I saw that you did experiments during that video, but then I saw that some of the experiments were covered in the experiment videos of this Unit. I am wondering if ALL of the experiments in your teleclass are covered in the other videos in this Unit. Once again sorry if it is confusing. Have a great day!
Not quite sure I understand the question – are you looking for more experiments or more science concept explanation videos?
Hey Aurora! I was just wondering if all the experiments in your teleclass are covered in the other videos of this unit?
Okay, thanks!
To get started with electricity, work through Unit 10, then Unit 11 (magnetism) and then jump over to Unit 14. There’s a lot of content in there. So glad you know what you like!
Units 1-6 are the basics physics of motion, unit 9 is all about light (something you’ll need to learn if you want to do electronics) and 3 and 8 are all about chemistry. It’s a progression, but can you skip around and do it in any order.
I am a little confused. I know this is off topic (I didn’t watch the vid yet) and I have finished my 8th grade science early. I guess I’m supposed to do the other fields of science, but I really like electronics, and decided to do this for the rest of my year. But here’s my question: is there a Unit 1: Electronics? Because the farthest I see it Unit 10, so I just wondered of there was a Unit 1 as well.
I am not understanding your question – please ask again in a different way so I can help?
Hi misses Arora why can’t any electricity shock you at any grade?
Try it and see if it works. 3-12V may require a second battery pack.
Will a 3-12V buzzer work, too, or does it have to be 3-6V?
Yes – it does! The motor uses an “eccentric drive” to move the robot around. Try varying the weight the motor moves around as well as the arm length (moment arm) of the thing it’s jiggling to control more of how it moves. Also leg position matters.. have fine experimenting!
Hey Aurora. I just realised that the motors on the popsicle sticks were facing up-right. Does this afect the jiggleing?
No, not especially. If it does, it just means that you’re not quite in the center of the glue sticks and they are flopping around a bit. Nothing to worry about unless it starts to shake itself off the string, then you’ll need to readjust the placement of the glue sticks on the motor shaft.
Hi Aurora, it’s Andie. Is the cable car supposed to vibrate a lot? Or is it supposed to vibrate only a little.
Hi Andie! I’ve sent you a private email…
Hi Aurora, it’s Andie. On Tuesday, I found that my tri-stand LED was broken. One of its legs had broken off. How do I fix it?
Hi Andie! Can you send me a picture of the front and back of the buzzer? You can send it to my email here: aurora@superchargedscience.com If you have a short video you can send that also so I can help!
Hi Aurora, it’s Andie. In the teleclass video, your buzzer has wires but mine has snaps. I’m not sure how to hook it all up together! Can you help me?
It might, depending on the alarm’s voltage requirements – try it and see if you can get it to work!
Hi Aurora, it’s Andie. I have an electronic snap circut kit and I am using the alarm snap circut from it. Will this work?
Yes, it’s just an illustration of what a battery can look like on the inside. The image in the upper left is a better view of the windings.
HI, I probably missed it but is that item at the bottom of the screen at 32 minutes a battery?
Sure thing! Do a search on our website for “telegraph” and you’ll get instructions for building one!
Hi, We took a field trip to visit a war ship/ destroyer. They had radio operators called sparkers who sent messages in morse code. We got to try sending our names & then the operator would guess them. Is there a way we could make morse code senders to send it to each other from our desks or the living room?