Measuring Depth

• Microscope
• Prepared slide with 3 colored, crossed threads

1. Place a slide containing 3 colored and crossed threads on the microscope stage.
2. Determine the width (diameter) of the threads using the procedures from Exercise 3.
3. Locate a spot where all 3 threads cross each other at the same point. Use the fine focus control to focus first on the lowermost thread, then the middle thread, and finally, the uppermost thread. List the order of the threads from the top to the bottom, by indicating their color.
4. Focus on the top of the uppermost thread. Note the scale markings on the fine focus knob and record the calibrated reading directly from the fine focus control. Carefully rotate the fine focus and stop when the microscope is just focused on the upper edge of the next thread. Record the reading from the focus control below. The difference between the 2 readings is the depth (thickness) of the upper thread.