Static electricity is always a popular topic with our G3 scientists. Why? In part, I think it’s fun to learn about something that we all experience pretty much on a daily basis. When you walk across the floor in your socks and then get a shock when you touch the TV – that’s static electricity. When you see lightning flash during a summer storm – that’s static electricity. [FUN FACT: Did you know that lightning not only goes from clouds down to the ground, but it can also go from cloud to cloud and from ground to cloud?] And the list of static electricity examples could go on and on.
To get us ready for the day’s experiments, we first briefly discussed what static electricity is and how it can be created. All matter is made up of tiny things called atoms. And in each atom, there are protons (+), neutrons, and electrons (-). Normally, an atom has an equal number of protons and electrons, so the atom itself is neutral with no charge. But if the conditions change and there are more protons in the atom, then that atom becomes positively charged. Likewise, if the conditions change and there are more electrons in the atom, that atom becomes negatively charged.
Take as an example the static electricity reaction you sometimes see after you comb your hair. When you drag a comb through your hair, the comb is attracting the electrons from the atoms in your hair. The comb becomes negatively charged as electrons stick to it, and your hair becomes positively charged as the electrons are removed from it. Your hair strands would be drawn toward the comb if you held it above your head – opposite charges attract each other. On the other hand, your strands of hair try to push away from each other because of their like charge – like charges repel each other.
We watched a few youtube videos to get us in the right scientific frame of mind as well, some of which are included below. Bill Nye the Science Guy talks about how a Van de Graaf generator works; a news report shows us why you should never talk on your cell phone or keep your car running while you pump gas at a gas station; and a family shares a cute home video about how static electricity can even have an impact on the loveable family pet :)
OUR PROJECTS FOR THE DAY: Leyden Jars and Floating Tinsel Orbs!
- Empy 35mm film canister with lid (or similar sized object)
- a paperclip (with one part stretched out straight)
- tin foil
- glue (we used glue sticks)
- Balloons (for creating the static charge we stored in the leyden jar)
I pre-cut strips of tin foil for all to use (approximately 2″ x 5″). Step one was smoothing out the foil and putting some glue on the less shiny side. We then wrapped the foil on the outer side of the empty film canister, making sure the foil was as smooth as possible. [The foil should overlap slightly.] There should be excess foil in the length that gets folded under the bottom of the film canister as well. Next, we pushed the straight edge of the paperclip through the center of the film canister lid. We then pulled the lid off and filled the container about 2/3 to 3/4 full of water. [You can dissolve some salt in the water if you'd like to try and enhance how well the static electricity is carried through the device.] With the lid back on and in place (the straight edge of the paper clip should be in the water), we just needed to charge our leyden jars.
This is the tricky part. We rubbed balloons on our clothes and hair to create a static charge, and then we touched the balloons to the PAPERCLIP ONLY to transfer that charge to the leyden jar. It’s very important that you only touch the paperclip; if you touch the plastic part of the case’s lid, you will neutralize (or eliminate) the charge. Likewise, you have to be very careful to ONLY TOUCH THE TINFOIL WRAPPING for the very same reason. Once we touched the paperclips with our balloons 3 or 4 times, we could then test the jar by hopefully giving ourselves a shock!
To test the jar, you first put the thumb of one hand on the tin foil. With that same hand, you SLOWLY approach the paperclip with another finger from that same hand. If all is successful, you will feel a small shock (the same level of shock you might get by touching the TV after walking across a rug in a pair of socks). With the lights out, you might even be able to see the spark that occurs between your finger and the paperclip. All of my tests before the program were a success. Sadly, we had less success during the programs themselves…in part (at least for the Track B program) because it was a rainy, humid day. When there is extra moisture in the air, the water molecules in the air attract a portion of any charge you create and thus make it more difficult to build up a decent charge on the balloons, in the jars, etc. We did have a few G3 scientists successfully feel the shock though!
For fun, I also showed our scientists a really fun trick that just requires a balloon and some tinsel (the kind of tinsel strands some people put on their Christmas trees!). First, you take a few strands of tinsel and tie them together in a knot at each end. You probably don’t want your “orb” to have strands longer than 4-5 inches. Next, you charge your balloon by rubbing it against your hair, clothes, or any other item that you think might help. The trick itself takes a little practice, and often a few attempts. But when successful, you drop the tinsel onto the charged balloon and after it quick touches the balloon’s surface, it then bounces off and floats above the balloon in mid-air! Why does this happen? Initially, the balloon and the tinsel have opposite charges and are attracted to each other. But once they touch, they carry the same charge…and as you know, like charges repel. Thus, the floating tinsel orb!
We had more successes with this trick than the leyden jars, I think. In fact, check out one of our successful moments below…and I’ll be talking with you again after our next program!