As you can see, both the right terminal of diode and top terminal of the resistor is negative.
This has something to do with shorting the negative terminal of an oscilloscope, but I don't under stand why. Why do these terminals both need to be negative?
From what I remember, the negative terminal of an oscilloscope is ground, so if the top resistance is positive, there will be a short circuit. I don't have any idea what that is or if that really was what I heard.
The experiment was to find the I-V characteristics of a diode.