Question

A student wants to find out if the amount of bleach has an effect on stain removal.

He plans to use two white shirts, stain each of them with mustard, and then wash each of them using bleach. He can change the size of the stain on the shirt and the amount of bleach he adds to the water.

Which test should the student set up?

Answer 1

Bleach is a Base, it’s a natural indicator which tells us whether the substance is a acid or a base.

Answer 2

The second option.

Step-by-step explanation:

We're trying to test the amount of bleach that has an effect on the stain so that is the altered variable.

The 2nd option uses different amounts of bleach to clean the same amount of stain.

If you choose the other options, people can argue that the bigger stain would be harder to clean with one cup of bleach, whereas the small stain gets two cups or the other way around.

It's not an effective way to see if the amount of bleach has an effect on stain removal.