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The first step on the road to a thermometer was taken by one Philo of Byzantium , an engineer, in the second century BC. He took a hollow lead sphere connected with a tight seal to one end of a pipe, the other end of the pipe being under water in another vessel.

To quote Philo: “…if you expose the sphere to the sun, part of the air enclosed in the tube will pass out when the sphere becomes hot. This will be evident because the air will descend from the tube into the water, agitating it and producing a succession of bubbles.

Now if the sphere is put back in the shade, that is, where the sun’s rays do not reach it, the water will rise and pass through the tube …”

No matter how many times you repeat the operation, the same thing will happen.

In fact, if you heat the sphere with fire, or even if you pour hot water over it, the result will be the same.”

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d, how likely is it that a group of people can set a uniform standard? We need to construct a device of some kind that responds to temperature in a simple, measurable way—we need a thermometer. <span>The first step on the road to a thermometer was taken by one Philo of Byzantium, an engineer, in the second century BC. He took a hollow lead sphere connected with a tight seal to one end of a pipe, the other end of the pipe being under water in another vessel. To quote Philo: “…if you expose the sphere to the sun, part of the air enclosed in the tube will pass out when the sphere becomes hot. This will be evident because the air will descend from the tube into the water, agitating it and producing a succession of bubbles. Now if the sphere is put back in the shade, that is, where the sun’s rays do not reach it, the water will rise and pass through the tube …” “No matter how many times you repeat the operation, the same thing will happen. In fact, if you heat the sphere with fire, or even if you pour hot water over it, the result will be the same.” Notice that Philo did what a real investigative scientist should do—he checked that the experiment was reproducible, and he established that the air’s expansion was in response to heat