It is done by taking advantage of one of two facts: firstly that the electrical resistance at the junction of two different metals (a thermocouple) varies according to the temperature, and secondly that the volume of a body varies with its temperature. In the first case a constant voltage is applied to the junction of the two metals, and the resulting current is measured with an ammeter calibrated in degrees of temperature; as the temperature at the junction varies, so will the current flowing and therefore the indicating hand on the dial of the instrument. The distance between the thermocouple and the indicator is immaterial, and this form of measurement is very suited to remote temperature reading.

It is spring now. Usually we HAVE good weather in spring, but sometimes it is raining. It is raining now too. I don’t like such weather, I LIKE when it is sunny. My parents aren’t at home now. They are working. They WORK five days a week. My younger brother ARE PLAYING chess with his friend at the moment. He often PLAYS chess after school when it IS rainING. I DO my lessons in English. I write a very difficult exercise. I also listen to music. I always listeN to music when I WAS doING my home task in English. Our pet Bobby plays with a ball. He likes playing with a ball. I often takE him for a walk. My brother feeds him three times a day. The birds sing merrily outside though it is raining. The sun doesn’t shine.

It is spring now. Usually we HAVE good weather in spring, but sometimes it RAINS. It is raining now too. I don't like such weather, I LIKE when it is sunny. My parents aren't at home now. They are working. They WORK five days a week. My younger brother IS PLAYING chess with his friend at the moment. He often PLAYS chess after school when it rains. I'm doing my lessons in English. I AM WRITING a very difficult exercise. I'm also listening to music. I ALWAYS LiSTEN to music when I do my home task in English. Our pet Bobby IS PLAYING with a ball. He likes playing with a ball. I often TAKE him for a walk. My brother feeds him three times a day. The birds ARE SINGING merrily outside though it is raining. The sun ISN'T SHINING.