Idea 6of 9Builds onThe tollThe push
Push, flow, fight
Twice the fight, same push. How much flow?
Today you'll discover
- how the push, the flow and the fight are tied
- the dimmer switch in one line
- a rule that gives any one from the other two
Think first12 V across 6 Ω: 2 A. Double the fight
Same 12 V, but a bulb that fights the flow twice as hard. The current?
Predict first, then drag the dials. Watch the current follow the push and fight the ohms.
A loop with a battery and one bulb, current arrows drawn. After a prediction, the Ohm's-law bench opens with sliders for the battery voltage and the bulb's resistance and readouts for the current. The last step asks the resistance of a heater from its volts and amps.
See the whole ideathe big idea and the key word, in one place
The big idea
Ohm's law: push equals flow times fight, V = I R.
Why it happensThe current is what results. The battery sets V, the component sets R, and I = V ÷ R follows. Nothing in the loop chooses the current directly.
Key word
- Ohm's law
- the voltage across a component equals the current through it times its resistance: V = I R
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?
- Use V = I R to find any one of voltage, current and resistance from the other two.