# The Physics of Vacuums: Understanding Force and Gravity

• oneamp
In summary, the force associated with a vacuum is atmospheric pressure, which counteracts gravity and allows liquid to be pushed up a straw. This phenomenon was explained in a lecture by Professor Walter Lewin.
oneamp
What is the force associated with a vacuum? If I put a straw in a soda and pinch off the end of the straw, then lift it out of the soda, some soda stays. What force counteracts gravity?

It is the atmospheric pressure that pushes the liquid up the straw.Since you reduce the pressure inside the straw the downward force on the liquid is only the force of gravity, the upward force due to pressure remains so the fluid goes up. If you try to do this with a very long straw you would reach a point where the weight of the fluid column is greater than the force due to the atmospheric pressure and the fluid would fall.
prof Walter Lewin did an amazing lecture on this here:

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## 1. What is a vacuum?

A vacuum is a space that is completely devoid of matter. It is often referred to as an "empty space" or a "void". In scientific terms, a vacuum is a space with a pressure lower than atmospheric pressure.

## 2. How are vacuums created?

Vacuums can be created artificially by removing air or other gases from a container. This can be done using a vacuum pump or by cooling the air until it condenses. In nature, vacuums can also be created by volcanic activity or meteorite impacts.

## 3. What is the relationship between vacuums and force?

In a vacuum, there is no air resistance or friction, which means that objects can move more freely and with less resistance. This allows for the application of force to have a greater impact on the movement of objects in a vacuum compared to in a non-vacuum environment.

## 4. How does gravity work in a vacuum?

In a vacuum, gravitational forces still exist and act on objects. Gravity is a force of attraction between objects with mass. In a vacuum, there is no air resistance or other external forces to counteract the gravitational force, so objects will fall towards each other with a greater acceleration compared to in a non-vacuum environment.

## 5. What is the significance of studying the physics of vacuums?

The study of vacuums is important in many fields of science, including physics, chemistry, and engineering. Understanding how force and gravity behave in a vacuum can help us better understand the laws of physics and how they apply in different environments. It also has practical applications, such as in the design and operation of vacuum pumps and other equipment used in scientific research and industrial processes.

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