Idea 5of 6Builds onPaying with a pushHow fast you pay
Warmth is where it went
The winch is warm after lifting. Why?
Today you'll discover
- what a machine does with the part it does not bank
- why warmth counts as a store
- the name for energy spread into particles
Think first240 J in, 196 J banked, and a warm motor
The winch spent 240 J; the crate banked 196 J. The motor is warm. What are the other 44 J?
Decide first, then press Next. Watch the third bar take the missing joules.
An energy ledger for a winch lifting a crate: a hollow bar for the joules put in, a bar for the height energy banked, and a third bar for warmth. After a prediction, the warmth bar is labelled with the missing joules, then the total line shows the bars adding back to what went in. The last step shows a pendulum climbing back a little short and asks where the missing joules are.
See the whole ideathe big idea and the key word, in one place
The big idea
Warmth is a store: thermal energy, spread into particles.
Easy to get wrongWarmth is not a fluid that leaks out and is gone. It is energy spread into the random motion of particles, harder to gather up but every joule still there.
Key word
- thermal energy
- the energy of the random motion of a thing's particles; where most 'lost' energy ends up
About this modelThe bars move energy between stores; the total only changes when work is put in or taken out.
The bars move energy between stores; the total only changes when work is put in or taken out.
Ready to use it?
- Account for missing joules by naming the thermal entry that balances a machine's ledger.