Question

A group of students were testing different insulators. They used three metal cans, one wrapped with bubble wrap, a second with a paper towel, and third unwrapped. Equal amounts of hot water were poured into each can and the temperature was noted at definite time intervals. The data is shown in the table.
From the data, they concluded that bubble wrap was the best insulating material. What is the weakness in the conclusion?
A) It is the better of two insulators only; it is not the best insulator.
B) The experiment should have been continued till the temperatures of the cans reached 0°C.
C) The experiment must be repeated at least three times before this conclusion can be drawn.
D) The data on the can without insulator is irrelevant and distracts from the main idea of the experiment.

Answer 1

Answer:

A)

Explanation:

The insulator is a material that creates a barrier for the heat transferred, maintaining the temperature of the system almost unaltered. To know what is the best insulator, the experiment needs to be done with an unwrapped can, so that is possible to know how much heat the can be lost, thus letter "d" is incorrect.

The temperature of the water would not achieve 0°C, but the ambient temperature, being in thermal equilibrium, so the letter "b" is also incorrect.

By the data given is already notice the insulator power, because the temperature decreases faster with the paper towel, thus it's not necessary to repeat the experiment only to know which one is better, so the letter "c" is incorrect.

But, it's not possible to affirm that the bubble wrap is the best insulating material, because exists a lot off insulating material that wasn't tested. Besides, the insulation depends on the thickness of the material.

Answer 2

Answer:

A

Explanation:

The term “best” means that there is nothing better. The student cannot conclude that bubble wrap is the best insulator after having tested only two insulating materials. It is the better of two insulators only; it is not the best insulator.