Understanding Pascals Principal in detail

[DOCMUR]

Hello

I'm a grade 12 physics student from WCI high school in waterloo ontario.
recently or class was studying pascals principal and it stated that it only worked using liquids. The textbook said some thing around the lines of:

when the small piston pushes on the liquid in the closed container the pressure is spread evenly in the container and the big piston will move to lift the heavy load.

The problem was the textbook about 2 pages later stated that pascals principal only worked for liquids and not gases. I cannot see how Gases can not be used to achive a simular effect. If the small piston pushes on the gas will the gas not spread the pressure evenly inside the container there fore achiving the same effect as the liquid.

If some could help can privide with a good reason to why this is either true or false that would be great.


Thanks DOCMUR

 

[Hurkyl]

Gases can much more readily display a different phenomenon when you press on a side of their container...

 

[thepatientmental]

Hello DOCMUR,

Thank you for sharing your question and thoughts on Pascal's principle. Let's dive into it in detail.

Pascal's principle states that when pressure is applied to a confined fluid, the pressure is transmitted equally in all directions throughout the fluid. This means that if you apply pressure to one point in the fluid, that pressure will be transmitted to all other points in the fluid, regardless of its shape or size. This principle is the basis of many hydraulic systems that are used in everyday life, such as car brakes and hydraulic lifts.

Now, to address your question about why Pascal's principle only works for liquids and not gases. The key difference between liquids and gases is their ability to be compressed. Liquids are considered to be incompressible, meaning that their volume cannot be reduced by applying pressure. On the other hand, gases are compressible, which means their volume can be reduced when pressure is applied.

In the case of a hydraulic system, the incompressibility of liquids is what allows the pressure to be transmitted equally throughout the fluid. When the small piston pushes on the liquid, the pressure is transmitted to all other points in the liquid, including the larger piston, causing it to lift the heavy load. This is because the liquid cannot be compressed and therefore, the pressure is distributed evenly.

On the other hand, if we were to use a gas in the same hydraulic system, the gas would be compressed when pressure is applied to it. This would result in a decrease in volume and an increase in pressure in only specific areas of the gas, instead of being evenly distributed. This uneven distribution of pressure would not allow the gas to transmit the pressure equally to all other points in the gas, making it impossible to achieve the same effect as using a liquid.

I hope this explanation helps to clarify why Pascal's principle only works for liquids and not gases. Keep up the curiosity and keep questioning the concepts you learn in class. It will only deepen your understanding of physics. Best of luck in your studies!