# A resistance Investigation

Essay by ggJunior High, 7th gradeA+, April 2002

PLANNING:

Aim: To find out the affect on the resistance of certain wires when a variable is changed. Are shorter, fatter wires or longer, thinner wires best for transferring the energy per second in the context of designing a heating element?

Investigation 1) To find out how the length of the wire affects the resistance of the wire.

Investigation 2) To find out how the diameter of the wire affects the resistance of the wire.

Prediction:

Investigation 1) I predict that as the wire increases in length the resistance (collision of particles causing a decrease in velocity for the moving particle) will increase, I think this will happen because there are thousands of electrons and ions in the wire, when the voltage is applied, the negative electrons move through the wire whilst the positive ions stay in the same position. The electrons are attracted to the positive end of the battery, the electrons move so that they collide with the ions and the sides of the wire whilst moving along through the wire.

The electrons which are pushed around by the voltage (force pushing electrons around the circuit); this causes the electrons to collide, to slow down the velocity of the current (movement of electrons) within the wire. This makes me think that if the wire is longer, and thinner the resistance will be a lot greater than if the wire was shorter and thicker. The longer the wire the more ions there are throughout the wire so the moving electrons will have a greater collision rate with the ions and the side of the wire, therefore increasing the resistance. The longer the wire the more ions there are for the electrons to collide with, which means that there will be more resistance.

Long Wire Short Wire

This shows that...