Question: How will you calculate the height of a building using the data from a Barometer?

There is only one way to calculate the height of a building using only a barometer as the measuring instrument.
You take the reading at the top, then the reading at the bottom, and express the pressure difference in terms of the density of air. The height of the building is the height of the air column necessary to cause the observed difference in air pressure between the top and bottom of the building.

Mutilated Question: "Show how it is possible to determine the height of a tall building with the aid of a barometer."

With the aid of ... You do not have to use the barometer in any way, you just have to secure its help. Sell it, buy lunch, eat and thus fortified, sally forth to measure the building in any one of a thousand odd ways.

Let's see what the NEW SCIENTIST has to say about it: This is from one of their newsletters.

Now, during the course of my wanderings on the web I came across a page which considers this and proceeeds to answer it in a dozen or so ways.
It is at http://www.esmerel.com/circle/question/building.html.

Let us review their answers. In particular, what instruments do we need?

1. Measure the barometric pressure at the top and at the bottom
Fine. Just the Barometer.

2. Drop the barometer and time how long it takes to fall
Brother, Don't waste the barometer. Grab a stone, call it "Barometer" and drop that. The result will not be affected. You'll need a stopwatch too.

3. Use the barometer as a measuring stick
You'll need a scale (to measure the length of the barometer).

4. Offer the barometer to the superintendent
Well ... What if the lab people want their Barometer back? No Go.

5. Measure the shadow of the barometer and the building
Measuring Tape, in addition to the Barometer. And a sunny day.

6. Measure the shadow of the building, calibrated by the barometer
As above.

7. Find a barometer with heights of local buildings on it
Well, the question will have to be amended to "with the aid of money to buy a barometer..."

8. Compare the barometer height to the building height
Measuring Tape, in addition to the Barometer.

9. Trade the barometer for a long measuring tape
And then you go back to the hardware store, and trade again for that barometer.

10. Drop the barometer on the roof and on the ground
You'll need a pretty sophisticated setup, to measure the small time intervals involved with the necessary accuracy. An electronic counter/timer. Start/stop sensors. And an evacuated chamber.

11. Use the barometer as a pendulum
... A pendulum reaching from the top of the building to the ground, that is. Lots of String. Stopwatch.

12. Drop the barometer on a windless day
Gas spectrometer, to measure the concentration of mercury vapour. And a windless day. Mercury Vapour being toxic, it would be nice to evacuate the area of people and pets before trying it.

13. Seal the building and fill with water
Then you measure the water pressure at the bottom. Waterproof cement, lots of it.

14. Take the building to an airless world
The space shuttle? To the moon? The mind Boggles. I give up.

15. . . .

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