- #1

Kaxa2000

- 71

- 0

I know it's true for Kelvin but I'm not sure about Celsius.

You are using an out of date browser. It may not display this or other websites correctly.

You should upgrade or use an alternative browser.

You should upgrade or use an alternative browser.

In summary, the discussion is about whether doubling the temperature in Celsius also doubles the pressure in a container. It is confirmed that this is true for Kelvin but not necessarily for Celsius. The equation (T2/T1) = (P2/P1) can be used to determine the change in pressure, but it should be noted that it only works if the temperature is measured in absolute units. The paradox of using Celsius or Fahrenheit units is also discussed, with the conclusion that the ideal gas law does not apply at very low temperatures. The Kelvin scale is directly related to pressure, with 0 Kelvin being equal to 0 pressure. However, at zero pressure, the Celsius scale has a negative value.

- #1

Kaxa2000

- 71

- 0

I know it's true for Kelvin but I'm not sure about Celsius.

Physics news on Phys.org

- #2

mgb_phys

Science Advisor

Homework Helper

- 7,903

- 15

Just trying a couple of values should convince you.

And in you system what would happen to the pressure if you went from 0C to 1C?

- #3

Kaxa2000

- 71

- 0

Which equation do I use to figure out if celsius doubles?

(T2/T1) = (P2/P1)

Do I use that?

(T2/T1) = (P2/P1)

Do I use that?

- #4

mgb_phys

Science Advisor

Homework Helper

- 7,903

- 15

Almost, P1/T1=P2/T2=constant.

But a moments thought about what is double 0C should be enough.

You should also consider if changing the temperature by the same amount measured in C or F should have the same effect on pressure ?

Suppose you heat something from body temperature to the boiling point of water.

In C that's 37 -> 100 = 2.7x

In F that's 97 -> 212 = 2.2x

How does the gas molecules know what units you are using ?

But a moments thought about what is double 0C should be enough.

You should also consider if changing the temperature by the same amount measured in C or F should have the same effect on pressure ?

Suppose you heat something from body temperature to the boiling point of water.

In C that's 37 -> 100 = 2.7x

In F that's 97 -> 212 = 2.2x

How does the gas molecules know what units you are using ?

Last edited:

- #5

Kaxa2000

- 71

- 0

I still don't understand your explanation mgb

- #6

mgb_phys

Science Advisor

Homework Helper

- 7,903

- 15

I am trying to prove that this only works if you have an absolute 'temperature' ie. one that goes linearly from zero.

If you have a temperature that doesn't start from absolute zero you get some ridiculous answer, such as increasing the temp from freezing (0C) to 1C would mean an infinite increase in pressure.

And raising the temperature from body heat to boiling would give a different pressure change depending on what units you used.

Since these are impossible - it must be that you have to use absolute temperautre.

- #7

Kaxa2000

- 71

- 0

Ok thanks mgb...it makes more sense now...but couldn't you also have 0 Kelvin?? So wouldn't an increase from 0K to 1K do the same thing ?

Last edited:

- #8

ideasrule

Homework Helper

- 2,286

- 0

Think about what happens when a gas, say air, goes from 1 degree Celsius to 2 degrees Celsius. (This is hot enough that the ideal gas law applies, so we're safe in using this thought experiment.) Celsius temperature doubles, but the room in your air doesn't suddenly double in volume when the temperature goes from 1 degree Celsius to 2.

- #9

Kaxa2000

- 71

- 0

So we usually talk about Kelvin at around 273K and above which prevents using 0K. Isn't the Kelvin scale directly related to pressure since 0K = 0Pressure? but at zero pressure the celsius scale has a negative value.

Last edited:

- #10

mgb_phys

Science Advisor

Homework Helper

- 7,903

- 15

From 0C to 1C is 274/273 = 0.3% increase in pressure.

Doubling the Celsius temperature will also double the pressure. This is because temperature and pressure are directly proportional to each other, meaning that as one increases, the other also increases.

The relationship between Celsius temperature and pressure is direct proportionality. This means that as the Celsius temperature increases, the pressure also increases at the same rate.

No, doubling the Celsius temperature is not the only factor that affects pressure. Other factors such as volume and number of particles also play a role in determining pressure.

The ideal gas law, PV = nRT, explains the relationship between Celsius temperature and pressure. According to this law, when temperature (T) is doubled, the volume (V) and number of particles (n) remain constant, resulting in a doubling of pressure (P).

Yes, the relationship between Celsius temperature and pressure can be applied to all gases under ideal conditions. In real-life situations, other factors may affect the relationship, but for ideal gases, the direct proportionality between temperature and pressure holds true.

- Replies
- 5

- Views
- 2K

- Replies
- 7

- Views
- 1K

- Replies
- 16

- Views
- 2K

- Replies
- 2

- Views
- 1K

- Replies
- 7

- Views
- 2K

- Replies
- 7

- Views
- 1K

- Replies
- 2

- Views
- 2K

- Replies
- 41

- Views
- 4K

- Replies
- 19

- Views
- 2K

Share: