STATIC ELECTRICITY

This page contains Physics contents discussed in class and re-written by students in prose form to show how well they understood the materials with some elements of creativity and link to the holistic being that the school is promoting through the P.I.A.G.E.T. values. Classmates read the contributions when doing home revisions and/or serve as peer support to others may have fall short of the standard, failed to earned the content-based badges.

Contributions in this page are also part of the 5% PROJECT component of the Final Grade in each term of the school year.

The Atom

Tips from Alycia, 7 August 2020

A neutral atom has the same number of protons and electrons. An atoms becomes charged when electrons are moving away or into the atom. When this happens, it becomes either a negative ion or a positive ion.

• An atom becomes negatively charged, should be called now a negative ion) when electrons flow into the atom and the number becomes larger than that of protons (electron > proton).

• An atom becomes positively charged, now called positive ion, when the electrons leave the atom and the number of protons is now larger than that of the electrons ( electron < proton).

• A charged atom is called an ion, as you may have noticed already in my explanations above.

Why not protons move in and out of the atom to change the charge? Why only electrons?

This is because protons are located in the nucleus, which makes them harder to move in and out of the atom, while electrons are outside, revolving around the nucleus, so they are easy to move. You may also look into the idea that the number of protons defines an atom. If protons are removed from the atom, consequently, an atom, say copper in our house wires, should become something else. This doesn't happen though, which proves that it isn't the one leaving or being gained by an atom but the other, electrons.

I will explain now how positive and negative charges interact? Please see this a s a result of observations in the lab and modeled by Physicist using lines of force we just studied this week.

• When two negatively charged rods or two positively charged rods are brought close to each other, they will repel. Lines of forces are shown in the figure below.

• When a positively charged rod and a negatively charged rod are put close together, they will be attracted to each other. See how the lines of forces interact leading to attraction between unlike charges.

Charge, just like distance, speed, pressure, density, force, and others we studied in previous terms, is also a physical quantity. It is measured using coloundmeters as other quantities as also measured by specific tools. Furthermore, like the others, it also given a unit, which is called coulomb having the symbol C. As measured, the magnitude of charge carried by protons and electrons are 1.6 × 10⁻¹⁹ C, with given + and - representing the charge type, respectively.

Charging by Friction

As explained by Angelyne, 7 August 2020

When it comes to static electricity, things are categorized into either insulators or conductors. Both of these kinds can be charged or given an excess of electrons or left with fewer electrons than protons. Charging by friction is a method of electrostatic charging which is used for charging electrical insulators. This occurs when two objects are rubbed together and the electrons are being transferred from one material to another.

The two objects in the above gif are insulators. Thus the electrons that are transferred are not able to move around and remain at the surface where the material has been rubbed.

Here is my explanation of how charging by friction takes place in the above scene.

The second way to charge by induction is charging a single metal conductor by induction. The equipment used in this method are your finger ( for grounding, because the human body is a good conductor), a metal conductor on an insulator, and a positively charged rod. These are the steps:

Those were the two methods of charging by induction. It is all quite simple, just remember that like charges repel and unlike charges attract and this should be pretty easy to understand.

Lightning

As explained by Hyun Bin, 9 August 2020

Have you ever been aghast by those threatening lightning? Have you wondered why and how that phenomenon occurs? Since all of SPA’s promising future scientists are filled with curiosity and integrity to learn, this article will be a little and simple secret map in order to satisfy your curiosity.

We all experience thunders and lightning in our daily lives. Especially in the rainy season in Indonesia, we experience lightning very often. Some may be shocked by the deafening thunder, and some might see the terrifying lightning. Before going deeper into lightning, it’s important to know what’s the difference between the lightning and the thunder. I may have confused you because I used the word lightning and thunder. Some of you may have thought that lightning and thunder was the same thing. My answer to that statement based on hours of researching, is a “no”. Well, lightning and thunder always comes together. However, the difference is that lightning is the electrical charge that you can see from those clouds. In easier terms, lightning is the light! Whereas thunder is the threatening sound that we hear after the lightning strikes. During thunderstorms, I’m pretty sure most of us experience this. You are sitting in your room staring at the window. Soon later, you see outside suddenly getting brighter because of the lightning. Then a few seconds later, you will hear the roaring thunder. That is mainly because of the speed of light being faster than the speed of sound. You see the lightning first and later, you hear the lightning( which is called a thunder). It is known that every 5 second is equivalent to one miles, meaning if you heard the thunder 5 seconds after the lightning, the lightning struck somewhere one miles away from your position. If you hear the thunder right after the lightning, I suggest you evacuate and follow the safety precautions. (Will be explained later).

Being hit by lightning sounds like things that happen only in movies. However, people do get hit by lightning as they lose their lives. Research showed that in the US, an average of 49 people per year die due to lightning strikes. That’s not much considering that almost 40000 people die due to car accidents in the US every year. Lightning doesn’t seem to be a deadly disaster that takes away people’s life these days. This is mainly because humans developed and learned methods to avoid those disasters caused by lightning strikes. Back in the ancient times, people actually got killed by lightning because they had no knowledge about how to keep themselves safe from the lightning strike. These days, scientists and engineers studied ways to avoid being damaged by lightning. First method is to use the metal rod. Metal rods are installed in some buildings to transfer the massive energy from the lightning to the deep ground. Metal rod on the top of the building is connected to the ground, and since the metal rod is a good conductor of electricity, instead of the lightning destroying the building and burning them, it is transferred to the ground. Second way is more simple. Stay indoors! I’m pretty sure that nobody in SPA enjoys running outside while thunderstorms. Being in closed areas like buildings and houses are mostly considered to be safe. Just in case if you were walking outside and suddenly the lightning occurs with heavy rain, my advice is to go inside somewhere. Being inside a car is also safe during the lightning. It’s also important to remember never to shelter under a tree during thunderstorms. Tall trees are a great target for lightning because there’s plenty of moistures in the tree and the leaves to attract the lightning since those moist are a better conductor than the air.

So, in this article, we have discussed what lightning is, how it occurs and how to avoid it. Despite the fact that the article is quite lengthy, I wish this is intriguing enough for all of the scientists of SPA. Writing this article really reminds me of my memories in science class back in Y7. The first thing I learned from Mr. Marlon was to be always curious about the topics and show the eagerness to learn something new. I hope this article will be an accelerant to achieving that goal.

Thank you.

Uses of Static Electricity

As explained by Jin Sol, 8 August 2020

How?

The metal drum inside the photocopier is coated with a photoconductor* called selenium.

*Photoconductors can only conduct electricity in the presence of light.

However, the metal drum is positively charged on the entire surface. This is because the metal drum is rotated near a highly-charged wire. The original image that should be photocopied will be placed on a sheet of the clear glass above the metal drum. As an intense light beam will be shone on the image, the darker areas of the image will reflect less light and lighter areas will reflect more light to the drum. Therefore, the areas of the metal drum will be conducting and discharged. Since the metal drum is kept on rolling, the image on the drum that is positively charged will attract the negatively charged toner powder in the toner cartridge. When the positively charged paper passes over the drum surface, the toner that is negatively charged will be attracted by the paper from the metal drum. After the paper is heated and pressed, this will permanently fuses the toner to the paper.