Explain the task to each other again in your own words.

State what you understood the task to be and what is still unclear to you.

We’re supposed to find out the teacher’s objective in conducting the experiment and exactly how the experiment will be carried out.

It is best if you first describe exactly what you can recognize and what purpose the various objects probably have.

The test tube contains two matches with their heads at the bottom. When the test tube is heated from the outside, the matches will probably catch fire. The test tube is sealed with a balloon; this is probably to prevent anything from escaping.

Think about what this experiment might have to do with your lessons up to now.

We have conducted experiments with a burning candle and ignited steel wool.

The candle became lighter, the steel wool heavier.

The question afterwards was: Do substances become lighter or heavier when they are burned?

The answer can be checked with this experiment because the test tube is sealed.

The purpose of the experiment is to check whether the mass of the involved substances changes when they react with each other during combustion.

How exactly does the teacher have to proceed in order for this to be revealed?

First, the test tube with its contents and the balloon must be weighed.

Next, it is heated so that the matches burn.

Finally, the test tube is weighed again.

Now you have all the information you need to answer the question coherently.

The experiment is intended to reveal whether the mass of the involved substances changes during combustion.

To find this out, the test tube must first be weighed, then heated so that a reaction takes place, and then weighed again.

Because nothing can get in or out of the test tube, we expect that the mass will stay the same.