↑ Speed = ↑ Temperature ↓ Speed = ↓ Temperature

How does a thermometer work?

2

1. A glass tube is filled with red colored alcohol because it expands and contracts easily (low vapor pressure).

2. As the temperature increases the molecules in the liquid move faster and expand filling the tube.

3. The glass will also expand but just a very small amount that is negligible.

4. We put markings on the side of the thermometer so we can measure how much the temperature changes by (calibration).

5. Temperature scales are arbitrary and comparative (man-made)

6. As the temperature cools the liquid contracts and drops down.

• Substances Expand when Heated• Substances Contract when Cooled

T↑ V↑ T↓ V↓

--50

--40

--30

--20

--10

--0

FAHRENHEIT Based on human body. ~100°F is the temperature of the human body 0°F is the coldest George Fahrenheit could chill brine to. Water:

– Freezing point is 32°F– Boiling point is 212°F

CELCIUS Built around water and most of the world uses it. Water:

– 0°C is the freezing point– 100°C is the boiling point

KELVIN scientific scale built on molecular motion. Absolute zero (0°K is the coldest possible temperature reachable and its where molecular motion stops. Water:

– 273.15°K is the freezing point– 373.15°K is the boiling point

°F °C °K

Absolute Zero

Freezing Point

Room Temp.

Boiling Point

0°K

273.15°K

293.15°K

373.15°K

-273.15°C

0°C

20°C

100°C212°F

32°F

68°F

-454.76°F

Create a Graph.

• The y-axis should range from -200 to 400.

• Draw in a line with a slope of 1 beginning at the 0 mark. This represents the temperature in Celsius.

• Draw in dots that represent the freezing and boiling point on the Celsius scale.

• Now add in dots for the freezing point and boiling point on the Fahrenheit and kelvin Scale.

• Draw in these lines in different colors.

• Compare the Celsius and Kelvin temperature scales?

• Will the lines ever cross? Why or why not?

• Come up with a formula for converting between Celsius and Kelvin.

°F °C °K

Absolute Zero

Freezing Point

Room Temp.

Boiling Point

0°K

273.15°K

293.15°K

373.15°K

-273.15°C

0°C

20°C

100°C212°F

32°F

68°F

-454.76°F

-200

0

200

400

600

800

1000

Temperature ScalesC F K

Tem

pert

ure(

°)

Temperature Conversions Formulas

① While in Europe the weather man says it will reach 30°C. Should you wear a jacket? What temperature is that in Fahrenheit?

② A Turkish friend wants to bake you some Baklava and he needs to set your oven to 180°C. What temperature in Fahrenheit should he set the oven too?

③ Coffee is brewed at about 91°C, what temperature is this on the Kelvin scale?

④ Covert 50°F into Kelvin! (two steps!)1. Figure out which formula to use.

2. Plug in what you know.3. Solve

Temp. Alive or Dead Why?

100°C

100°K

80°C

300°K

Temperature. Alive, Dead, Jacket or Beach Why? (°F)

-40°C

31°C

85°C

10°C

305°K

0°K

283.15°K

1. The number of cups in a gallon plus the number of teaspoons in a cup is the temperature in °F. Convert it into °C and °K

2. Mr. Sapone pushes you down a steep hill into a pond that has 4 alligators in it. Each alligator has 78 teeth. The total number of alligator teeth is the temperature in Fahrenheit. Convert it into °C and °K.

8

Calibrating a Thermometer Lab