What does a temperature below zero mean?

In this lesson you will learn how to use positive and negative numbers by thinking about situations with temperature.

Let’s Review Positive Numbers Negative Numbers

A Common Mistake Writing -20 degrees as -20 degrees below zero

Core Lesson 100 CelsiusFahrenheit Boiling point of water Freezing point of water

Core Lesson A thermometer is just like a vertical number line

Core Lesson A fever: 102 degrees F (38.9 C) A really hot day: 110 degrees F (43.3 C) The sun: 10,000 degrees F (5,537.7 C)

The starting temperature is at - 5 degrees and then drops 10 degrees. What would the new temperature be?

Core Lesson What about if we start at a positive temperature and drop 15 degrees?

Core Lesson 20 degrees below zero or -20 degrees

Did you know? Fairbanks Alaska: -6 degrees F

In this lesson you have learned how to use positive and negative numbers by thinking about situations with temperature.

Guided Practice 1. You have a fever and your temperature goes up 2 degrees. Is your new temperature a positive or negative number? 2. It is a very cold day, and the temperature drops to 20 degrees below zero, how would you write this? Positive -20

Extension Activities Look at weather reports for different parts of the world and try and find examples of extreme high and low temperatures. Where are some really cold places?

Pick a location that changes a lot in temperature from summer to winter. Look at the average monthly temperatures. Graph the temperatures. If there are negative temperatures, be sure to show these on your graph correctly.

Put a thermometer in a glass of warm (not hot) water and measure the temperature. Start adding ice cubes, 1 at a time and see what happens to the temperature. How cold can you make it? Graph the temperatures.

Quick Quiz 1. Water boils at 100 degrees Celsius. Is this a positive or negative number? 2. One of the coldest temperatures in Nebraska is 47 degrees below zero Fahrenheit, how would you write this?