I:\7th Grade\Energy\Heat Notes 2010

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Warm up

1. Are fossil fuels renewable or nonrenewable?

2. Explain your answer to question 1.

3. What are some examples of fossil fuels?

Guest Speaker…Michelle Grossman, a meteorologist from NBC 10 news will visit our team on Friday.

We would like to send her some questions today so she knows what we are interested in.

Please write 3-5 questions you have on the index card at your table.

I will collect them and send our questions to Mrs. Grossman this afternoon.

Heat

Why does it seem like warm water is burning when you have just come in from being outside on a very cold winter day?

The way we feel temperature is subjective; our hands/body are not good indicators of temperature!

Which has a higher temperature?

Which has more KE? TE? Heat?

Why?

Thermal energy: depends on temp. AND amount the total energy of the particles

Temperature:

an average of KE

so KE would be equal for both

BUT, TE (overall KE) of the teapot would be larger

Why?

Why does a stethoscope feel colder than a tongue depressor?

Your back is heating the stethoscope!!

Heat is a transfer of thermal energy between objects that are different temperatures;

Energy always moves from higher-temperature to lower-temperature

Heating stops when the objects are the same temperature

Explain the energy transfer shown below:

Misconception Alert

The thermal energy is related to temperature and state of matter.

So… equal masses of liquid water and steam at the same temperature (1000C) have different amounts of thermal energy. Why?

Steam stores energy used to separate the particles of liquid water, so steam has more thermal energy than liquid water.

Special ceramic tiles were created for use on the underside of the space shuttle. These tiles transfer so little energy that one side can be exposed to a welder’s torch while the other side remains cool to the touch!

Conductors

Conductors transfer thermal energy well

Iron skillet

Cookie sheet

Copper pipes

Coils on stove

Curling iron

Demo….*Observe the demonstration.

*Explain what happened.

Metals used:

1. Brass hub2. Aluminum Rod3. Brass Rod4. Steel Rod5. Nickel Rod6. Copper Rod

1.

2.

3.

4.

5. 6.

Insulators

Insulators transfer energy poorlyFlannel PJ’s

Fiberglass

Oven Mitt

Ceramic bowl

Plastic spatula

How do these work?

As the metals are heated, what happens to their particles?

Explain thermal expansion in relation to the experiment with the ring and ball.

How does thermal expansion work in these?

Bimetallic strip:

Thermostat:

DEMO… Use what you know about the

transfer of thermal energy to describe the demo…

Convection

Transfer of thermal energy by the movement of liquid or gas

How exactly does this work?

Where can we see examples of this?

DEMO…

Use what you know about the transfer of thermal energy to describe the demo…

Radiation

Transfer of energy through matter or space as EM waves (ex: visible light, infrared, etc)

Where can we see examples of this?

How do we measure temperature?

3 Scales:FahrenheitCelsiusKelvin

What is absolute zero?

Problems: Use your textbook, page 153, to answer

the following:

1. 24C to ?F 2. 17C to ?F 3. OC to ? F 4. 482F to ?C 5. -4F to ?C 6. 98.6F to ?C

Readings: Read the articles on pages

180-181 of your textbook. Summarize one of them.