The experiments I most vividly recall are the one where he stacks the books overlapping in a staircase fashion until the top book's inside edge is past the bottom one's outside edge, the vacuum pump that sucked liquid up the side of a building, and, of course, the enduring celery-in-the-food-coloring trick:
You can see water go up the stem to the leaves of a plant by trying this experiment. Cut off an inch of the bottom of a celery stalk with leaves. Put the celery into water colored with ink. In about an hour the leaves and stem are streaked with color.Link (PDF). To mark the passing of the great Don Herbert, let's all stick a stalk of celery (with leaves) in a glass of inky water today.
Cut off another small piece from the bottom. Notice the colored spots along the cut end. These are the ends of little tubes through which the water rises in the stalk. Cut the stalk lengthwise and follow the tubes up to the top.
Indexed by tags science, television, education, Mr. Wizard, Don Herbert.