Question
Question: Which of the following represents a physical change? (A) Stretched rubber band. (B) Melting of I...
Which of the following represents a physical change?
(A) Stretched rubber band.
(B) Melting of Ice cream.
(C) In winter, hair oil freezes.
(D) All of the above.
Solution
Hint : We know that the physical change alters the form of a substance, but do not change it to another substance. It changes shape or size. It dissolves. It changes phase. When a substance undergoes a chemical change, it is changed into a different substance with different properties.
Complete Step By Step Answer:
Matter is anything that has space and mass. Matter is always experiencing both physical as well as chemical change. Chemical changes are changes matter undergoes when it becomes new or different matter. Temperature changes without heating or cooling. It bubbles, burns, changes color and forms a precipitate. E.g. Precipitation, color change, gas production etc. A chemical change occurs when fireworks are used. They are made up of magnesium and copper. These change chemically as they light up the sky. Physical change occurs when matter changes its property but not its chemical nature. Physical property changes could include a change in texture, shape, size, color, odor, volume, weight and density. E.g. A boiled egg. No new substances are formed. It involves very little absorption of energy.
Thus, all of the following represents a physical change i.e. stretched rubber band, melting of ice cream and in winter hair oil freezes.
Therefore, the correct answer is option D.
Note :
Remember that boiling water to give vapor is a physical change because it is reversible. The water vapor can be cooled to give water. Melting of ice to give water is also a physical change. There is a change in the phase of the matter.