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Unit 6: HeatUnit 6: Heat

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What is heat?What is heat?Water boils at 100◦ C

Lava has an average temperature of

1000◦ C

Sparklers burn at 2000◦ C Sparklers burn at 2000 C

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What is heat?What is heat?Why would you be severely

burned by lava (or even boiling

t ) b t th k f water) but the sparks from

the sparkler are harmless?

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What is heat?Are there limits to how hot or how cold Are there limits to how hot or how cold something can get?

Wh d til fl f l ld hil th Why does a tile floor feel cold while the carpeted floor feels warm at the same temperature?temperature?

Why does hot air expand by hot water vapor contracts?

Why does ice form on the top of the Why does ice form on the top of the pond, not the bottom?

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What is heat?

Do you have any questions about heat or temperature?temperature?

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Learning Goal:I can define temperature and heat and

can describe the relationship between themthem.

Based on what you already know, could y yyou:

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

are different? are different?

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The Kinetic Theory of Matter

What does kinetic relate to?

What is matter?

Kinetic = Motion

What is matter?

Matter = Particles with mass (atoms)

What is a theory?

Theory = a scientifically tested ideaTheory a scientifically tested idea

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The Kinetic Theory of MatterTh ti l th t k tt The particles that make up matter are

always moving.They have kinetic energy because of their They have kinetic energy because of their

movement.

They move in different ways:

Straight line (translation)

Rotating (Spinning)

VibratingVibrating

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The Kinetic Theory of MatterP ti l h ll th t f ki ti Particles can have all three types of kinetic

energy (translational, rotational and vibrational))

Particles also have potential energy from attractions or repulsions between each other

Thermal Energy is the total energy in a particular substance and is thought of as internal energy

10 Heat vs Temperature

TemperatureWhen you hit a nail with a hammer, it

becomes warm. Why?When you light a candle in a jar the jar When you light a candle in a jar, the jar

becomes warm. Why?

In each of these examples, the particles gain kinetic energy.

I l th bj t th In general, the warmer an object, the more kinetic energy its atoms possess.

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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.

12 Heat vs. Temperature

Heat vs. TemperatureHeat

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

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Heat vs. TemperatureHeat vs. TemperatureExample: the Fourth-of-July-type sparklerTh k th t fl f th fi k d The sparks that fly from the firework and

strike your face have temperatures in excess of 2000°C, but they don’t burn.

Because the thermal energy of the sparks is extremely low. Even though the kinetic energy/particle is very high only a few energy/particle is very high, only a few molecules actually touch your skin.

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Heat vs. Temperature

1 liter of boiling water

2 liters of boiling water

Temperature? Temperature?Same Same

Heat? Heat?Less More

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ReflectionReflectionMark your calendar!

Today’s learning goal:I can define temperature and heat and can I can define temperature and heat and can

describe the relationship between them.

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