# Understanding Pascals Principal in detail

• DOCMUR
In summary, the conversation discusses the use of Pascal's principle in lifting heavy loads using liquids. The textbook mentions that this principle only applies to liquids and not gases, which raises questions about whether gases can achieve a similar effect. The conversation ends with a request for clarification on the difference between the behavior of liquids and gases when pressure is applied.
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

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

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!

## 1. What is Pascal's Principle?

Pascal's Principle, also known as the principle of transmission of fluid-pressure, states that pressure applied to a confined fluid at any point is transmitted undiminished throughout the fluid in all directions.

## 2. How does Pascal's Principle relate to hydraulics?

Pascal's Principle is the foundation of hydraulics, which is the study of fluids in motion and the application of that study to engineering. Hydraulics uses Pascal's Principle to amplify force and transmit power through the use of pressurized fluids.

## 3. Can you provide an example of Pascal's Principle in action?

One example of Pascal's Principle is the operation of a hydraulic car lift. When a small force is applied to the small piston, it creates a larger force on the larger piston due to the transmission of pressure throughout the fluid. This allows the lift to easily raise a heavy car.

## 4. What is the mathematical equation for Pascal's Principle?

The mathematical equation for Pascal's Principle is P1 = P2, where P1 is the pressure at the smaller piston and P2 is the pressure at the larger piston. This shows that the pressure exerted by the smaller piston is equal to the pressure exerted by the larger piston.

## 5. How is Pascal's Principle related to Archimedes' Principle?

Pascal's Principle and Archimedes' Principle are both based on the properties of fluids. While Pascal's Principle deals with the transmission of pressure, Archimedes' Principle deals with the buoyancy force exerted by a fluid on an object immersed in it. Both principles are important in understanding the behavior of fluids and their applications in engineering.

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