Science educator and magician Bob Friedhoffer recently shared a demonstration that he performs with an immersion hand blender and a glass of water. The demo is very simple, yet the physics behind it is not so obvious. He first submerges the blender's blade in a glass of water. With the blade near the bottom of the glass, he turns on the blender and, voilà, lifts the glass and its contents off the table!

Bob reported that he has tried producing the effect with glasses and cups having different shapes and sizes. In some cases lift was achieved; in others it was not. Perhaps not surprisingly, he has also found that some blenders work better than others. He said that a particularly powerful blender once allowed him to pick up a small aluminum sauce pan.

It has been suggested that the Bernoulli effect is responsible for the lift. However, the jury...

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