The Graviscope

This graviscope is a very sensitive device for measuring gravity force. The device is extremely simple and can be built at home.

The force of gravity between two objects with equal mass of one tonne each one, that are separated by a distance of one meter is only about 0.006 gram. The gravity force is so weak that we need some huge laboratory equipment to detect it.

How can we see a gravitational interaction between small bodies with a weight of some kilogram? The devices which can detect this weak interaction should have extremely high sensitivity.

But anyway, we can built very simple gravity detector using only plastic and glue. The construction of this device is very simple, and anyone can build it yourself.

The graviscope - the instrument to measure gravity force

Home made graviscope - view from the top

The base of this device is a transparent vessel (1) made of a transparent plastic material. The vessel inside is partially separated by a partition (2) into two parts. The partition wall that does not reach half the way to the bottom and it protrudes outside the vessel. Two transparent pipes (3,4) are mounted in the vessel at the both sides of the partition wall. The cross section of each pipe is 1 mm2 (the diameter of the pipes is about 1.12 mm). Two another pipes (5,6) of larger diameter are connected to the vessel. Each of this pipes has a tap on it. Be sure that all joints are airtight.

How to use the graviscope

Place the graviscope horizontally on a table or shelf. Put into each small pipe one drop of a colored liquid. Be sure that both drop are leveled against each other. After that, fill the vessel with water or any other liquid through the other pipes until the lower part of partition wall is completely submerged, but leave a small air gap (2..3 mm) between the water surface and the lid of the vessel. When the liquid in the vessel calms down, close the taps. The device is ready to use.

If we now put a massive object near graviscope's side, or a human comes close to it, then the surface of the liquid inclines for a little because of the gravity force. The liquid will moves from one side to the other side of the vessel, which closer to the massive object or human. Because of this movement, the air under the lid will moving too, so the painted drop in the pipes will moves. In our case the painted drop on the right side of the vessel will raise, and the painted drop on the left side will goes down. If the massive object will be removed from the right side of the vessel, then both drops will moves in opposite directions. The same will happen if we put the massive object near the left side of the vessel.

The sensitivity of the graviscope depends on a ratio between the diameter of small pipes and the area of surface of the liquid. For example, if the area of surface of the liquid in each side of the vessel is 80 mm2, and the cross section of each pipe is 1 ΠΌΠΌ2, then the change of the liquid level for one micron will change the distance between two colored drops for some centimeters. It is enough to see the gravitational interaction between the massive object and the liquid in the vessel.