# Physics barometer help

1. Oct 17, 2013

### astru025

1. The problem statement, all variables and given/known data

Two barometers are made with water and mercury. If the mercury column is 32 in. tall, how tall is the water column?

2. Relevant equations

3. The attempt at a solution

2. Oct 17, 2013

### SteamKing

Staff Emeritus
Well, do mercury and water have the same density? Which column do you expect would be taller?

3. Oct 17, 2013

### NihalSh

What are barometers used for?........what do mercury and water have in different in relevance to this question?

4. Oct 17, 2013

### astru025

Mercury has a higher density so the water column will be higher. This doesn't really help me much though

5. Oct 17, 2013

Usually barometers are used to measure the atm. so if you know it,then you can use the equation to calculate the height of water if you know the density of water. Not so difficult. :)

EDIT:Do you know the equation relating height density and all that.If you have studied barometers you should know it.

6. Oct 17, 2013

### SteamKing

Staff Emeritus
Are you sure about that? What is the density of mercury relative to the density of water?
If a constant pressure P supports a mercury column 32 in. tall, don't you think that the height of the mercury column is somehow related to how dense mercury is?