We consider uplift

Investigate in the experiment the situation where a test object is immersed in a measuring cylinder placed on a scale. Analyze the results of the experiment. Answer the question.

What are we dealing with here

If a stone becomes lighter under water, it does not mean that the force of gravity on the stone decreases. The buoyant force, which partially compensates the force of gravity, is created by the water around the stone. The water seems to push the stone upwards.

But if the water pushes the stone upwards, the same force should push the water downwards, i.e. the weight of the water should increase.

This also means that the weight of the vessel containing the water with the body immersed in it increases by exactly the same amount as the buoyant force acting on the body.

How to conduct an experiment

In the experiment, we place a measuring tape with water on a scale and then submerge a weight suspended from the end of the dynamometer into the water.

Experimental data and calculations

We remind you that scales convert the force acting on them into mass. We can get the weight from the mass using the formula $F = m g$ . Let's take $g = 10 m / s^{2}$ .

Weight reading before the test object was immersed in water ( $[g]$ )
The weight of the measuring glass before the test object was immersed in water ( $F_{1}$ , $[N]$ )
Weight reading after the test object was immersed in water ( $[g]$ )
The weight of the measuring glass after the test object was immersed in water ( $F_{2}$ , $[N]$ )
The upward force acting on the test object is therefore ( $F_{2} - F_{1}$ , $[N]$ )