Question Video: Understanding Positive and Negative Numbers Describing Real-World Quantities Having Opposite Directions or Values

Video Transcript

What temperature, in both degrees Celsius and Fahrenheit, does the thermometer show?

On the left side of this thermometer, we have degrees Celsius and on the right side, we have degrees Fahrenheit. The scale on the left — the scale for Celsius — is counting by tens. Between each of these labels is 10 tick marks. On the right with Fahrenheit, between each of the labels is 20 marks. The range between each label on the Fahrenheit side is 20 degrees.

To measure temperature, we’ll need to see how far up the red goes on our scale. If we look closely at our red line, on our Fahrenheit side, the red mark falls halfway between the 20 and the 40. Halfway between 20 and 40 is the number 30. This thermometer is showing 30 degrees Fahrenheit.

On the Celsius side, we see that the red line is below zero. It is the first tick mark below zero. One mark below zero on this graph represents negative one degrees. It is negative one degrees Celsius.

Using these two different units of measure to find the same temperature, we see that negative one degrees Celsius is equal to 30 degrees Fahrenheit.