Solution to Activity 3.2 of NCERT Class 8 Science Chapter 3 Coal and Petroleum

2. Complete Activity 3.2 (Page 32).

(It is a group activity). Take some containers. Fill them with popcorn/peanuts/roasted gram/toffees. Divide students into
groups of seven each. Further divide each group into three subgroups containing 1, 2 and 4 students. Label them as first, second and third generation respectively. These sub-groups represent the consumers. As population is growing, second and third generations have larger number of consumers.
Put one full container for each group on a table. Ask consumers of the first generation from each group to consume eatables from the container of their group. Now, ask the second generation consumers from each group to do the same. Ask students to observe carefully the availability of eatables in each container. If some thing is left in the containers, ask third generation from each group to consume it. Now, finally observe whether all the consumers of the third generation got the eatables or not. Also observe if anything is still left in any of the containers.

Answer:

The above activity can be carried out as follows:

Aim: To observe the how many eatables are available after each generation finishes eating and also whether there is enough for each generation and make the necessary conclusions.

Materials Required: 5 containers with popcorn.

Procedure:

(i) The students in my class were divided into five groups of 7 each.

(ii) Each group is divided into three subgroups of 1, 2 and 4 students. The subgroups are labelled as first, second and third generation respectively.

(iii) One container is placed on a table for each group.

(iv) Now consumers of the first generation from each group are asked to consume eatables from their group’s container.

(v) Then consumers of the second generation from each group are asked to do the same. Observe the availability of eatables in each container.

(vi) If there is any popcorn left, the third generation from each group will consume it. Now observe whether all consumers of the third generation got the eatables or not and whether there is anything left in any of the containers.

Observations:

We observe that:

The number of eatables in the container decreased faster with each successive generation.
In 2 out of 5 groups there was nothing left for the third generations. The remaining three groups had enough for the third generations.

There was popcorn left in only one container after the third generation finished eating.

**Is There Enough:** After the first and second generations finish eating, is there enough for the third generation to consume? What does this tell us?

Conclusions:

We conclude that:

As population increases with each successive generation, exhaustible resources get depleted faster and faster.
We must be judicious about our usage of these resources now, so future generations can have enough of them.

Hence, Solved.