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
6
4
2
0
Negative
Numbers
-2
-4
-6
Positive
Numbers
A Common Mistake
Writing -20 degrees as -20 degrees below
zero
Core Lesson
Boiling point
of water
Freezing
point of
water
Celsius
Fahrenheit
100
212
50
90
0
32
Core Lesson
A
thermometer
is just like a
vertical
number line.
100
100
50
50
0
0
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)
Core Lesson
The starting
temperature is at 5 degrees and then
drops 10 degrees.
What would the
new temperature
be?
15
0
10
5
0
-5
-10
-15
-5
-10
-15
-20
-20
Core Lesson
What about if we
start at a positive
temperature and
drop 15 degrees?
15
5
0
10
5
0
-5
-10
-15
-5
-10
-15
-20
-20
Core Lesson
20 degrees below zero or
-20 degrees
Core Lesson
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
Positive
number?
2. It is a very cold day, and the
temperature drops to 20 degrees below
zero, how would you write this?
-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?
Extension Activities
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.
Extension Activities
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?