Different materials affect electrical resistance in unique ways. There's a helpful rule called Ohm's Law that explains this. It says:

V = IR

Here, V is voltage, I is current, and R is resistance.

We can also measure resistance using this formula:

R = ρ (L/A)

In this formula:

• R is resistance
• ρ (rho) is resistivity, which is a feature of the material
• L is the length of the material
• A is the area of its cross-section

Now, let’s look at how different materials compare:

1. Conductors (like Copper and Aluminum):

• Copper: Its resistivity is about 1.68 x 10^-8 Ω·m. That means it lets electricity flow easily.
• Aluminum: This has a resistivity of 2.65 x 10^-8 Ω·m. It also conducts electricity well, but not quite as well as copper.

2. Insulators (like Rubber and Wood):

• Rubber: This material has a very high resistivity of about 10^12 Ω·m. This means it doesn't allow electricity to flow through it easily.
• Wood: Its resistivity is around 10^10 Ω·m. Like rubber, wood is also a good insulator.

3. Semiconductors (like Silicon):

• Silicon: This material has a resistivity of about 2.3 x 10^-3 Ω·m. It can conduct electricity, but not as well as metals.

These differences show how materials can greatly impact electrical resistance. Understanding this helps us figure out how to use them in electrical systems.