Pressure and Boyle's Law

Plotting absolute pressure vs length allows for more precise measurements and eliminates the need for calculations.In summary, the difference between absolute pressure and gauge pressure is that absolute pressure includes atmospheric pressure. The reason for plotting absolute pressure vs length of the column in a J-Tube is for more accurate measurements and to avoid calculations.
  • #1
franz32
133
0
Hello guys, I got some problems again. Will you be able to help me?

What is the difference between the absolute pressure and gauge presure?

Why is the absolute pressure plotted vs the length of the column of the trapped air instead of the volume of trapped air in the J-Tube?
 
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  • #2
Originally posted by franz32
What is the difference between the absolute pressure and gauge presure?
absolute pressure = gauge pressure + atmospheric pressure

Why is the absolute pressure plotted vs the length of the column of the trapped air instead of the volume of trapped air in the J-Tube?
The length of the column is proportional to its volume.
 
  • #3


Hi there! We are happy to help you with your problems.

The difference between absolute pressure and gauge pressure lies in the reference point used to measure the pressure. Absolute pressure is measured with respect to a perfect vacuum, meaning there is no pressure at all. Gauge pressure, on the other hand, is measured with respect to atmospheric pressure. This means that gauge pressure takes into account the pressure of the atmosphere on top of the object being measured.

As for your second question, the reason why absolute pressure is plotted vs the length of the column of trapped air instead of the volume of trapped air in the J-Tube is because the volume of the trapped air is not constant. As the length of the column of trapped air changes, the volume of the trapped air also changes. Therefore, it is more accurate to plot absolute pressure vs length, as it takes into account the changing volume of the trapped air.
 

1. What is pressure?

Pressure is the force exerted on a surface divided by the area of that surface. It is typically measured in units of force per unit area, such as pounds per square inch (psi) or pascals (Pa).

2. What is Boyle's Law?

Boyle's Law is a gas law that states the relationship between pressure and volume of a gas, when temperature is held constant. It states that as pressure increases, volume decreases, and vice versa. This can be expressed mathematically as P1V1 = P2V2.

3. How does pressure affect gases?

Pressure affects gases by changing the volume of the gas. As pressure increases, the gas molecules are pushed closer together, resulting in a decrease in volume. Conversely, when pressure decreases, the gas molecules have more space to move and the volume increases.

4. What is the significance of Boyle's Law?

Boyle's Law is significant because it helps us understand the behavior of gases under different conditions. It also allows us to make predictions about how changes in pressure will affect the volume of a gas, which is crucial in many scientific and industrial applications.

5. How does Boyle's Law relate to real-world situations?

Boyle's Law is seen in many real-world situations, such as scuba diving. As a diver descends deeper into the water, the pressure increases, causing the volume of air in their scuba tank to decrease. This is why divers must continuously monitor and adjust their air supply to maintain a safe breathing pressure. Boyle's Law is also used in the production of canned foods and beverages, where the pressure inside the can is increased to prevent spoilage and maintain freshness.

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