What happens when you turn the coarse adjustment knob?

Coarse and fine adjustment The coarse adjustment knob should only be used with the lowest power objective lens. Once it is in focus, you will only need to use the fine focus. Using the coarse focus with higher lenses may result in crashing the lens into the slide.

If you turn the knob away from you, it will come closer to the slide. If you turn the knob towards you, it will move away from the slide/moves up.

Explanation:

the product of the pressure and volume is also constant