Unit 6: Heat1 Temperature

Unit 6: HeatTemperature Scales and

b l Absolute Temperatures

2 Temperature

Learning Goal:I can define temperature and heat and

can describe the relationship between themthem.

Based on what you learned yesterday, how y y ywell can you:

Define heat?D fi t t ?Define temperature?Describe how they are alike and how they

are different? are different?

3 Temperature

Review - TemperatureTemperature, which is the degree of

“hotness” or “coldness” of an object, is proportional to the average translational proportional to the average translational kinetic energy of the atoms and molecules make up the substance.

Temperature is not a measure of the total kinetic energy in a substancekinetic energy in a substance.

Temperature is not a measure of total thermal energy.

4 Heat vs. Temperature

Review - Heat vs. Temperature

Heat

1 Thermal Energy

Temperature

1 Average 1. Thermal EnergyKE + PE

1. Average Translational Kinetic Energy

2. For the whole substance

2. For each particle in the substance

3. Measured in calories or joules

3. Measured in degrees

5 Temperature

Learning Goal:I can define temperature and heat and

can describe how temperature scales are usedused.

Based on what you how well can you:y yDefine heat?Define temperature?What is a temperature scale?How is it used to measure temperature?

6 Temperature

Temperature Activity

7

Temperature ScalesWhat can you tell me about

temperature scales based on temperature scales based on our activity?

8 Temperature

Temperature ScalesTemperature is a quantity that Temperature is a quantity that corresponds to degree of hotness on a chosen scale.

A thermometer takes advantage of the fact the most substances expand with temperature.

A thermometer measures temperature A thermometer measures temperature by comparing the expansion or contraction of a liquid (red alcohol) in i t l increments on a scale.

9 Temperature

Temperature ScalesThe Celsius temperature scale is The Celsius temperature scale is the scale used most often in the world today.y

The scale is named after Anders Celsius who first suggested that a scale with 100º between the freezing and boiling point of freezing and boiling point of water would be a good idea.

10Temperature

Temperature ScalesThe Fahrenheit temperature scale The Fahrenheit temperature scale is the scale commonly used in the US.

On the Fahrenheit temperature scale, water freezes at 32º and boils at 212º.

11 Temperature

CHECK YOUR NEIGHBORCHECK YOUR NEIGHBORTrue or false: Cold is the absence of fast-

moving molecules. gFalse; cold refers to very slow-

moving molecules, not their moving molecules, not their absence.

12 Absolute Temperature

Absolute TemperaturesIs there an absolute upper limit and Is there an absolute upper limit and

lower limit temperature?

What would an maximum temperature be measuring?gIs there a point where the particles couldn’t move any faster?

Theoretically, temperature has no upper limit.

13 Absolute Temperature

Absolute TemperaturesWhat would an minimum temperature be What would an minimum temperature be

measuring?Is there a point where the particles

ld ’t l th t i th couldn’t move any slower – that is they are stopped?

Yes! The absolute lower limit for temperature is called Absolute Zerois called Absolute Zero

The particles have lost all their kinetic d ’t t ldenergy and can’t get any colder

14 Absolute Temperature

Absolute TemperaturesThe Kelvin temperature scale was The Kelvin temperature scale was

developed to help explain the relationship temperature and kinetic energy (movement)

0 Kelvin (K) is Absolute Zero273 K is the melting point of water (0º C)373 K is the boiling point of water (100º C)

15 Temperature Conversion

Converting Between ScalesConverting Between ScalesDo you think it is possible to convert a

t t d temperature measured on one scale to a different scale?

Yes! You just need to use an algebraic equation to convert from one scale to the other.

16 Temperature Conversion

Converting Between ScalesConverting Between ScalesºC = 5/9 (ºF - 32) ºC = K + 273

In FPS, we are going to use the Celsius scale f t for our measurements so you won’t need to convert!convert!

17 Temperature

ReflectionMark your calendar!Mark your calendar!

T d ’ l i lToday’s learning goal:I can define temperature and heat

and can describe ho temperat re and can describe how temperature scales are used.

Using the scale, how do you think you are doing with the concept?are doing with the concept?