EVERYDAY SCIENCE

Detailed explanation-1: -However, when you roast marshmallows a new substance forms. When you melt marshmallows, you are only changing the state of the marshmallows (i.e. solid and liquid marshmallows are the same substance). A physical property has changed, but the composition of the substance is the same. This is called a physical change.

Detailed explanation-2: -When marshmallows are roasted, a chemical change happens. When you toast marshmallows, the heat causes a chemical reaction producing water molecules, which then evaporate, leaving carbon behind (the blackened part of the roasted marshmallow).

Detailed explanation-3: -Convection is the process of heat transfer that involves the movement of a liquid or a gas. In this case, when you roast a marshmallow above the fire where the hot air is rising, convection takes place.

Detailed explanation-4: -The trick is to get the marshmallow a nice golden brown without catching it on fire. Too often we are not successful and we see the marshmallow burning on the stick – a combustion reaction taking place right in front of us.

Detailed explanation-5: -Some common examples of physical changes are: melting, freezing, condensing, breaking, crushing, cutting, and bending.