Idea 5of 9Builds onThe flow
The toll
Same battery, a thinner bulb filament. What changes?
Today you'll discover
- what fights the flow in a wire
- why a thin wire fights harder
- the name and unit of the fight
Think firstThe same 12 V, a thinner filament
The same 12 V battery, but a bulb whose filament is thinner. The flow?
Decide first, then press Next. Watch the flow shrink as the filament fights harder.
A loop with a battery and one bulb, current arrows drawn. After a prediction, the bulb is marked as the place where the push is spent, then the current is compared for a thinner filament. The last step asks the resistance of a thick wire joined straight across the battery.
See the whole ideathe big idea and the key word, in one place
The big idea
Resistance is how hard a part fights the flow.
Easy to get wrongA battery is not a constant-current source. It holds its volts; the flow depends on what you connect, on the resistance in the loop.
Key words
- resistance
- how much a component opposes the flow of current; thin, long and hot wires have more of it
- ohm
- the unit of resistance, symbol Ω: a fight that lets one volt drive one ampere
About this modelCharge is never used up: what leaves the battery comes back. Volts are what get spent.
Charge is never used up: what leaves the battery comes back. Volts are what get spent.
Ready to use it?
- Say which of two described parts has the higher resistance, and what that does to the flow.