A student can use a magnet to indicate that combining iron and sulfur produce a mixture of铁and sulfur is a physical change by following these steps:

Materials:

* Iron powder

* Sulfur powder

* Magnet

* Petri dish

* Mixing spoon

Procedure:

1. Place a small amount of iron powder in a petri dish.

2. Place a small amount of sulfur powder in the petri dish.

3. Mix the iron and sulfur powders together using the mixing spoon.

4. Bring the magnet close to the mixture.

Observation:

The magnet will be attracted to the mixture of iron and sulfur. This indicates that the iron is still present in the mixture and has not reacted with the sulfur.

-This is because iron is a magnetic material, while sulfur is not. Therefore, if the magnet is attracted to the mixture, it means that the iron is present and the two powders have not reacted.

Conclusion:

Based on the observation, it can be concluded that combining iron and sulfur produces a mixture of iron and sulfur, and this is a physical change. This is because the iron and sulfur powders have not reacted to form a new substance. The magnet is still attracted to the mixture, indicating that the iron is still present.