TEMPERATURE

The temperature of something tells us how hot or cold something is.

T

EMPERATURE

IS MEASURED IN

DEGREES

USING A

THERMOMETER

IS THE SYMBOL FOR DEGREES .

100

“100 Degrees”

A

thermometer

is an instrument that is used to measure temperature.

How to Read a Thermometer

Temperature is measured

37 C

on two scales:

Celsius

and

Fahrenheit

.

98.6

F

 Earlier in the century, Fahrenheit and Celsius used water as the basis of their thermometers. Their thermometers were calibrated using water, which everyone had access to. This made their thermometers useful to everyone. In the same way, the meter could be useful to everyone.

C ELSIUS

AND

F AHRENHEIT

.

 °F, the Fahrenheit Scale (used in the US), and°C, the Celsius Scale (part of the Metric System, used in most other countries)  They both measure the same thing (temperature!), but use different numbers :   Boiling water (at normal pressure) measures 100° in

Celsius, but 212° in Fahrenheit

And as water freezes it measures 0° in Celsius, but

32° in Fahrenheit

Celsius °C Fahrenheit °F

A measurement of temperature using a scale on which water boils at 100 degrees and freezes at 0 degrees. It is sometimes called centigrade.

A measurement of temperature using a scale on which water boils at 212 degrees and freezes at 32 degrees.

C

“C” is the symbol for the Celsius scale.

The Fahrenheit scale is the most popular in the United States.

F

Its symbol is “F.”

Let’s count by 2’s…

2, 4, 6, 8, 10, 12…

The lines on most thermometers count by two’s.

102 100 98 96 94 92 90 F

What is the temperature on this thermometer?

98 F “98 degrees Fahrenheit”

100 96 94 92 90 88 F

Try this one.

86 F “86 degrees Fahrenheit”

90 88 F 84 82 80 78 76

Normal body temperature is 98.6 F.

This means it is between 98 and 99 degrees.

98.6 F

This is a

decimal point

.

.

2 .4 .6 96 97 98 99

98.6 F

T HE TEMPERATURE IS “98

POINT

6” DEGREES F AHRENHEIT .

.

2 .4 .6 .8 97 98 99 100

99.8 F

The temperature is “99 point 8” degrees Fahrenheit.

99 100 101 102 What is the temperature?

101.2 F

Try this one.

100 101 102 103

102.8 F

N EGATIVE N UMBERS

The temperature scale is often seen vertically.

As the temperature goes below freezing we use negative numbers.

1 0 3 2 6 5 4 - 1 - 2 - 3 - 4 - 5 - 6 Getting warmer Water freezing Getting colder

SCALES

 In U.S the Fahrenehit scale is used.

 The Celsius scale is used in almost all other countries and by scientists.

Fahrenheit (1686-1736) established three fixed points on his thermometer.

0 degrees:

temperature of an ice, water, and salt mixture.

32 degrees

: water-ice combination stabilized at "the thirty-second degree."

98 degrees

: “when the thermometer is held in the mouth or under the armpit of a living man in good health." Celsius (1701-1744) established two fixed points on his thermometer.

0°C:

representing the freezing point of water.

100°C:

the boiling point of water.

PROBLEM

 Riki measured the outside temperature at noon and then again at 8 p.m. The temperature at noon was 6 °C. The temperature at 8 p.m. was – 2°C. What was the change in temperature? 1.

You can use the thermometer like a number line.

There was a _____change in temperature.

PROBLEM SOLVING

One day the lowest temperature recorded in Maine was -12 °F. The highest temperature in Maine that day was 25 °F. What was the change in temperature?

C ONVERTING   Looking at the diagram, notice: The scales start at a different number (0 vs 32), so we will need to add or subtract 32  The scales rise at a different rate (100 vs 180), so we will also need to multiply

C ONVERSION G UIDE   FORMULA Celsius to Fahrenheit: ( ° C × Fahrenheit to Celsius: ( ° 9 / 5 ) + 32 = ° F F − 32) x 5 / 9 = ° C

°C to °F °F to °C

Multiply by 9, then divide by 5, then add 32 Deduct 32, then multiply by 5, then divide by 9

•

Use the formula to change each 1 temperature to degrees Fahrenheit.

.

5 ° C 2. 35 ° 3. 20 ° 4. 15 ° C C C