It sounds like you're describing an organism with two cell layers, which is a characteristic of diploblastic organisms. Here's how to observe the second layer:

What the student should do:

1. Adjust the Focus: Since the two layers are likely very close together, the student will need to carefully adjust the fine focus knob of the microscope to bring the second layer into view.

2. Use Different Lighting: Adjusting the light intensity can help differentiate between the two layers. Sometimes, using a slightly lower light intensity can help see the details of the second layer.

3. Change the Objective Lens: If the second layer is very thin or transparent, switching to a higher magnification objective lens might be necessary to get a clearer view.

4. Prepare a Different Slide: If the organism is thick, a thin section (a slice) of the organism might need to be prepared to view the second layer clearly.

Important Note: Diploblastic organisms (like jellyfish and hydra) typically have an ectoderm (outer layer) and an endoderm (inner layer). The student should be able to identify these two layers based on their position and any distinct features visible under the microscope.