Question

classify the following as physical or chemical change and explain - growth, blinking, respiration, chewing.

Answer 1

1) Growth of a plant is not just a physical change but both physical as well as a chemical change. Physical because it involves changes in the shape and size of the tree (tree on growing becomes bigger in size and its branches spread out). Chemical because growth of a plant is a biochemical process which is regulated by plant hormones and enzymes.

2) Blinking of eyes is a physical change.

3) Respiration is a chemical change as in respiration Oxygen is assimilated into blood and CO₂ is released along with energy.

4) Chewing is a chemical change as saliva gets mixed with the food .