Static Electricity Flashcards
What is static electricity?
The build up of charge on insulating materials. It can cause sparks when it’s discharged.
Why do all materials contain charge? Why are they neutral?
Because all materials contain positive protons and negative electrons. They are neutral because the protons and electrons cancel each other out.
What does the friction between two objects do to electrons?
It causes the electrons to be rubbed off of one of the objects and onto the other one.
In conducting materials like metal where the electrons are able to move, the electrons just flow straight back again. Therefore, no charge ever builds up.
What happens when you rub two insulating materials together?
The electrons cannot flow back, so the transfer caused by the friction gives a positive static charge to the material that lost the electrons, and a negative static charge to the material that gained the electrons.
Which way the electrons get transferred each time depends on the specific materials involved.
True or False?
It is only the positive protons that get transferred between two materials when rubbed together.
False
It’s only the negative electrons that are transferred. The positive static charges occur because the object has lost negative charge, and NOT because it has gained positive protons.
What happens if an object keeps gaining negative electrons?
As more and more electrons get transferred, and the size of the charge increases, a potential difference will develop between the charged material and the earth, or any earthed object (like us, this is because earthed objects are always at 0V).
When the potential difference between the charged object and the earthed object gets large enough, then electrons can jump across the gap, and this jumping of electrons is what a spark is.
Note that charges can sometimes build up on conductors, too. It’s just much less common.
