EVERYDAY SCIENCE

Detailed explanation-1: -For example, changing the color of a metal does not change its physical properties. However, in a chemical reaction, a color change is usually an indicator that a reaction is occurring.

Detailed explanation-2: -A piece of metal may be heated in a fire until it glows, but the metal is the same material before heating and after cooling. Similarly, when a material changes phase, it only changes physically; the substance is still the same. Think about ice melting into water, and then water being heated up and turning into steam.

Detailed explanation-3: -Common physical changes include melting, change of size, volume, color, density, and crystal form.

Detailed explanation-4: -Application of heat to certain substances causes only physical changes in which no new substance or substances are formed. Application of heat to some substances causes chemical changes, or chemical reactions, in which one or more new substances are formed, with different properties from the original.

Detailed explanation-5: -The increase in the temperature of the metal is the result of the heat transfer from the produced fire using the lit match to the cold piece of metal. No changes in the chemical structure were observed which is why this process is due to a physical change.