Question

E. Answer the following questions in brief.
1) What are physical and chemical changes? Give an example of each.
il) a. What are joints?
b. Why are the last two ribs called floating ribs?
iii) How is transpiration useful to plants?​

Answer 1

A physical change is a change that is caused by physical effort .

Example :- Tearing of paper, melting etc.

• Chemical change is a change that is caused by chemical.

Example :- Burning of paper , Breaking of glass

• Ans 2. A Joint is an part of body that joints two bones
• AnsThe last two ribs are called the floating ribs because they are not joined with the spinal cord .

ANS 3. Transpiration is useful to plant as it clean the stomata holes that is blocked by dust .

Answer 2

1) Differences Between Physical and Chemical Change

Physical Change

When a substance undergoes a physical change, its composition remains the same despite its molecules being rearranged.

chemical change

When a substance undergoes a chemical change, its molecular composition is changed entirely. Thus, chemical changes involve the formation of new substances.

physical change

Physical change is a temporary change. A chemical change is a permanent change.

A Physical change affects only physical properties i.e. shape, size, etc.

chemical change

Chemical change both physical and chemical properties of the substance including its composition

water, melting of wax, boiling of water, etc. A few examples of chemical change are digestion of food, burning of coal, rusting, etc.

joints

ii)Joints are the areas where 2 or more bones meet. Most joints are mobile, allowing the bones to move. Joints consist of the following: Cartilage. This is a type of tissue that covers the surface of a bone at a joint.

floating ribs

The last false ribs (11–12) are also called floating (vertebral) ribs, because these ribs do not attach to the sternum at all. Instead, the ribs and their small costal cartilages terminate within the muscles of the lateral abdominal wall.

transpiration

The water, warmed by the sun, turns into vapor (evaporates), and passes out through thousands of tiny pores (stomata) mostly on the underside of the leaf surface. This is transpiration. It has two main functions: cooling the plant and pumping water and minerals to the leaves for photosynthesis.