A convenient form of energy

Electricity is the name commonly used for anything related to electrical energy. If something has energy it can work. Doing that work means energy is transformed from one form to another or that the energy is transferred from one object to another. As electricity is a type of energy, it obeys the Law of Conservation of energy. This law is extremely important for all modern humans to remember. 

Law of conservation of energy

The law says. "Energy can neither be created nor destroyed, but only rearranged in form." It’s a law because every time someone has tested or investigated the statement, their investigation has found it to be supported.

You can’t create electricity from nothing. It’s a form of energy.  A lot of other energy forms can be changed into electrical energy but we can't create electrical energy from nothing. The change of energy form one form to another is called a transformation. One way of creating electrical energy is by separating electric charges.

Charges

If an object has no charge then the number of negative charged particles called electrons is equal to the number of positively charged particles. Positively charged particles are tightly held in the centre of atoms called the nucleus but negatively charged particles called electrons are not and as a result are relatively easily separated from the nucleus.

All matter is made from atoms that contain electrically charged components. The atoms that join together to form everything around us, have positively charged protons in the atomic nucleus, with the negatively charged electrons orbiting around that nucleus in shells like a solar system. The amount of electrical charge a proton has is equal in size to the amount of charge an electron has but the charges are opposite. It is the electrons in the outer orbit shells around the nucleus that create the chemical bonds that hold atoms together. Usually the amount of positive charge in the nucleus is equal to the amount of negative charge from the orbiting electrons. This normally leaves the material uncharged, i.e. it has total of zero or no net electrical charge.

You might have just separated some electrons from the nucleus of some atoms already today creating a static electrical charge.  Sometimes you do that on purpose, sometimes it happens by accident.

Whenever two different materials come into contact with each other some charge will transfer from one material to the other. This is why, when you comb your hair or try to polish a sheet of plastic, you experience "static electricity" and objects gain an electrostatic charge. The child slid down the slide and either lost electrons or gained electrons. Dry hair is a poor transfer of electrons. This means it's an insulator. The hairs on the child’s head were all charged the same. Like charges push away from each other and so do objects carrying a like charge. That means the hairs were trying to get as far away from each other as they could and the result was a wild hairdo.

Try this investigation

To do this you will need a balloon and you will need to be close to a water tap. Inflate the balloon. Rub the balloon against your clothes for about 30 seconds to give it an electric charge. Turn on the tap so as to produce a light steady stream of water. Bring your balloon close to the water stream. What happens?  Did you see your water stream get attracted to the balloon and bend? Does it bend more when the balloon is closer?  What does that mean? 

If you can’t do this investigation you might like to watch a movie  about it

This attraction of the uncharged water stream to the charged balloon is due to the electric field surrounding the charged balloon. All electrically charged objects have an electric field around them. Objects with the same charge repel. Objects that are uncharged are attracted to, and attract charged objects. Objects that are charged differently, one positively and one negatively attract each other.

To use an interactive simulation of this activity visit the interactive learning guide, download the balloons activity and explore charging a balloon. You can then observe the interactions of charged objects.

In class you will probably use charged rods to explore electrostatic charges and electric fields. There are three basic rules to remember when dealing with charge, i.e.   

Static electricity
Static electricity means electricity that stays still. The electrical charges aren’t moving. That doesn’t mean that they will always stay still. Electrons carrying the negative electrical charge want to move away from where they are more highly concentrated to where they are less concentrated. They do this by jumping from one spot to another. When they jump, they often cause a sound and produce a visible spark. You might have seen this if you take off a jumper made from synthetic material such as fleece in front of a mirror in the dark. Small flashes of light and heat are electrons jumping from one spot to another to even out the level of charge.

Sometimes you might get a shock from static that builds up when a car travels. This occurs when you either get out of a car or when you go to get into a car that has been travelling. Sometimes static electricity can be dangerous. This can include when static electricity ignites a flammable substance.

Static electricity is a common phenomenon. Lightning is an example of a static electrical discharge. Lightning can occur in dust storms, volcanic eruptions, and when thunder clouds form. 

Take a look at volcanic lightning and listen to this explanation of lightning as a phenomena

Lightning is an example of static electricity that shows you that electrical charge can jump from where it is out of balance. When this occurs across electrical connections it is called arcing. Arcing produces a flash of light and heat. Electrical transformer farms and facilities such as substations have devices and equipment carrying large electrical charges. They can arc to objects and the ground on occasions.

People who work at these facilities are trained to take great care and follow strict safety procedures to make sure they don’t have electricity arc to them and then on to the ground.

Remember - never enter a substation or electrical distribution facility because arcing is dangerous and could severely injure or kill you.