Cavendish Experiment

This animation depicts a modern version of the Cavendish experiment, where a twist of a wire measured by a deflecting beam of light helps determine the force of gravitational attraction between masses.

Category:

Education

Tags:

• physics
• physical
• science
• astronomy
• gravity
• gravitation

[nhmllr725]

How long did it take for the lead balls to touch? Days?

[mrg3]

@nhmllr725 There is a "springiness" in the suspension wire opposing the attraction. The point of the experiment is not to have them touch, but to measure the force gravity induces by measuring the small twist induced in the suspension rig.

To do this in real life, you'd want an enclosure to prevent even small air currents from messing up your measurements.

[infectedmordn]

what can this " Experiment " do?`

[mrg3]

@infectedmordn This experiment brings two masses close together and measures the force of their gravitational attraction exhibited here through the (exaggerated in this video) twist in the sire suspension of two of the masses.

Ultimately this provides a measurement of the constant which describes the strength of gravitational forces in Newton's Law of Universal Gravitation.

[kokocipher]

@Kenta19191919 That's a good question. I'd assume that they used magnify glasses to focus the sunlight to a point. Then for the mirror, it can be concave.

[kokocipher]

@dillmon1 yea, I'd love to see a video recording of a real experiment taking place. I wonder how big the setup has to be to see any results though xD

[kokocipher]

Wow, Cavendish is so smart. Notice that the mirror is on the balance of the smaller masses. This way, the rotation will be greater comparing to the larger masses. Cavendish also set it up so that there are 2 masses being attracted to each other at opposite ends, so the gravitational force is amplified by x2. 

[Kenta19191919]

@gerardtheretard

I see. Making it big - sometimes is the ultimate solution to work on small quantities.

[ASKaPHYSICIST]

Awesome animation!

Well, would you mind if I use it in my next video, with due credit of course?

[gerardtheretard]

@Kenta19191919 Cavendishes original experiment was huge thus the angle was easier to read

[gerardtheretard]

@nhmllr725 depending on the size (mass) of the balls it takes only a few minutes

[whydidigetdeleted]

@Kenta19191919 I did this experiment and used a simple electric lamp. If you used a raybox, you could use a candle.