Question

two metal blocks that have slightly different temperatures are placed next to one another. after five minutes, they both have lower but equal temperatures. according to the law of conservation of energy, what most likely happened?
energy was created inside the blocks.
energy was destroyed inside the blocks.
energy was absorbed into the blocks from outside the system.
energy was transferred from the warmer block to the cooler block.

Explanation:

The law of conservation of energy states energy can't be created or destroyed, only transferred/transformed. When two metal blocks with different temps are placed together, heat (a form of energy) transfers from the warmer block to the cooler one until thermal equilibrium. The first two options violate energy conservation. The third option isn't likely here as the system is the blocks; heat transfer between them (not external absorption) explains equalizing temps.

Answer:

D. Energy was transferred from the warmer block to the cooler block.