If I were teaching...I would instruct the students to use a "curves" adjustment layer, in normal mode. All the basic correction tools are included in the curves control.
Start with adjusting the white balance by moving the top of the curve in Red, Green, and Blue individually.
Then adjust the black balance in the same way, only using the bottom of the respective curves.
They should have the "info" window open so that they can see how the numbers change when using the eye dropper. They should be training their eyes, not using the aids to adjust white or midtones to neutral on gray or white parts of the image.
Next, adjust the white and black levels using RGB mode while holding down the "option" key to show white and black clipping.
Next, adjust the gamma in RGB mode by using just one point in the middle of the curve.
Fine tune color by adjusting the gamma in the individual R, G, and B curves.
And lastly, more points can be added to the RGB curve to adjust shadow and/or highlights to taste.
I think that this is the best approach to insure that the students understand color correction, and not short-cuts that don't involve as much thinking.