Video Transcript
The diagram shows a thermometer being used to measure the temperature of the air outside. What value does the thermometer give for the temperature?
Okay, so in this diagram, we can see that we’ve been given a thermometer. And a thermometer is used to measure the temperature of its surroundings. In this case, the thermometer has been placed in air. Now, if the air is very warm, then the thermometer itself warms up. And this red liquid that we see inside the thermometer warms up as well. As the red liquid warms, this surface of the liquid will rise inside the thermometer. And conversely, if the red liquid cools, then the surface will drop. And, of course, the red liquid heats up or cools down to match the temperature of the surroundings, in this case, the air.
And we see in this diagram that currently the surface of the red liquid is here. This corresponds to a reading of nine on the scale that’s given adjacent to our thermometer. The reason we know that the reading is corresponding to nine is because here we see zero and here we see five. These are the larger markings and the smaller markings in between these two large markings represent one, two, three, four, and then we have five here, just as we expect. Then, we have six, seven, eight, and then nine, which is what the surface of the red liquid corresponds to.
Lastly, we’ve been told beside the scale that this thermometer is measuring temperature in degrees Celsius. And therefore, this particular thermometer measures the value of the temperature of the air outside to be nine degrees Celsius.
