Which of the following is an example of a physical change?
evaporation in a swamp cooler
electricity produced by a dry cell
digestion of a hamburger
rusting of a car body

evaporation in a swamp cooler

Explanation:

Evaporation in a swamp cooler simply involves the conversion of water in the liquid state to water in the gaseous state. It is an easily reversible process if the vapour can be collected and condensed. A chemical change involves the formation of a new substance and is not easily reversible. It is a chemical reaction. A dry cell operates by a chemical change which produces voltage in the cell. Digestion involves a series of irreversible chemical reactions catalysed by enzymes. Hence the answer.

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).

a pan containing water is placed in a positio n where it is exposed to a 10 mile per hour wind. the pan contains a uniform depth of 1.27 cm of water, is quite wide, and has a length of 2.44 m in the wind direction. the water in the pan is at a constant temperature of 15.5 °c.