# Does a barrel explode if it's filled with water?

1. Jan 26, 2012

### titaniumpen

Pressure = density * gravity * height

I'm wondering what will happen if you fill a barrel completely with water and leave absolutely no air in it. Let's say the barrel is 1 meter tall. So the pressure from the water inside would be 1000*9.8*1 = 9800 N/m^2

But the atmospheric pressure would be 101,300 N/m^2

Difference between the two pressures would be 91,500 N/m^2.

Wouldn't that cause the barrel to collapse (implode)?

2. Jan 26, 2012

### titaniumpen

I'm pretty sure I got something wrong here. I don't see water bottles exploding...

3. Jan 26, 2012

### titaniumpen

My guess is that water is not easily compressible, so it holds the barrel.

4. Jan 26, 2012

### Staff: Mentor

Not easily compressible, but easily pressurize-able. (probably not a word, but it should be)

See, if you fill the water bottle while in the atmosphere, the weight of the water isn't the only pressure in action. You're filling the bottle against air pressure, so the water in the bottle is already compressed and pressurized before you close the top.

If you fill the bottle in a vacuum (problematic due to the water boiling, but bear with me...) and transfer it to the atmosphere, atmospheric pressure will compress it, pressurizing the water. The final volume in the second case will be slightly less than in the first case.

5. Jan 26, 2012

### titaniumpen

Thank you, I now understand. :D