The Effect of Air: Qualitative Testing Experiment

Aim

The aim is to test different models of the effect of the air on objects.

Prior Knowledge

  1. Springs
  2. Newton's Laws

Description of the Experiment

In this experiment, an empty 2 liter plastic soda bottle (with cap screwed on tightly) is hung from a low k spring attached to the top of a bell jar. You can note the stretch of the spring by looking at where the black mark on the bottle lines up with the ruler. The air is then pumped out of the bell jar with a vacuum pump. Use the different hypotheses that have been proposed to make predictions about what should happen to the black line relative to the ruler as the air is pumped out. In other words,

  • If the hypothesis is correct that the air pushes down on the bottle, what should happen to the black line as the air is removed?
  • If the hypothesis is correct that the air pushes up on the bottle, what should happen to the black line as the air is removed?
  • If the hypothesis is correct that the air has no net effect on the bottle, what should happen to the black line as the air is removed?
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