A middle or high school science teacher gave his students this scenario: you’re standing by a tall building, and you need to find out about how tall it is. All you have available is a barometer. How can you use that to find out how tall the building is?

The “proper” answer, of course, was to measure the pressure on the ground, and at the top floor (or roof, if you could get to it) of the building, and use the formula for air pressure reduction by altitude to get the altitude of the roof and thus height of the building.

But one of his students decided to “smart off” and said, “Drop the barometer from off the top of the building, and time how long it takes to hit the ground. Plug that into the formula for gravitational acceleration.”

They gave him a re-test. This time he answered, "Climb up the outside of the building, measuring the height in barometer-lengths ..." They stopped him. "No, no, that won't do!"

He said, "Approach the building superintendent and say, 'If you'll tell me the height of this building, I'll give you this expensive baromater." Again, they said, "No! You must give a scientific use of the barometer.

This time he answered, "Tie a string to the baromater. At the top of the building, measure the period of the pendulum. Do that same at the bottom of the building. From the difference we can calculate the height."

They said, "That's not what we want." He said, "Tell me what you want." And they found that they couldn't answer him without giving away the answer.

He had one method. "Measure the barometer's shadow. Measure the building's shadow. From similar triangles, we can calculate the height of the building."

They gave up and gave him back the points.

One can read this as a joke but then again you can think of it to be an inspiration to think different.

## Comments

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TopNewestThis smart off student is actually Bohr – Oussama Boussif · 3 years ago

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This is not any high school story but most probably Rutherford had asked this to Bohr and he had said that he had 13 different answers and asked Rutherford which one he wanted? – Tushar Gopalka · 2 years, 11 months ago

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Simply Amazing!! – Dhruv Bhasin · 3 years ago

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What can i say ! – Hassan Yousaf · 2 years, 2 months ago

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Regarding the 1st reply,since it is not vaccum around the building when the barometer is dropped due to air resistance it will not undergo the exact gravitational acceleration and thus time it will take to reach the ground will be more than actual ,so the height will also not come actual. Regarding the another reply,Is it sure that the building superintendent will tell the right height. Pendulum one,again it is not an ideal simple pendulum. Shadow one,if it is a rainy day,then. But really it was a good inspiration to think differently. – Siddharth Singh · 2 years, 6 months ago

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