1. What should I study for my Science Quiz
What should I study for my Science Quiz? Heat & Thermal Energy Wind Water in the Atmosphere

2. Slow-Moving Molecules
What is heat, anyway?
Temperature is a measure of the average amount of energy of motion for each particle of a substance
Slow-Moving Molecules
Cold Water

3. Fast-Moving Molecules
What is heat, anyway?
Temperature is a measure of the average amount of energy of motion for each particle of a substance
Fast-Moving Molecules
Hot Water

4. Where does the energy come from?
Nearly all the energy that heats our atmosphere comes from the sun.
Energy from the sun travels in the form of electromagnetic waves.

5. Where does the energy come from?
Not all sunlight reaches the ground. Some sunlight is absorbed or reflected before it reaches the surface.

6. Where does the energy go?

7. Where does the energy go?

8. Where does the energy go?
Not all surfaces absorb the sun’s energy equally.
The color and material on the surface will determine how much of the energy is absorbed and how much is reflected.
Grass
Water
Sand
Rocks

9. How does heat move?
HEAT is the transfer of thermal energy from a hotter object to a cooler one.
Thermal energy is moving from the air, which is warmer, to the snowman, which is cooler.

10. How does heat move?
Heat can be transferred in three ways: radiation, conduction, and convection.

11. RADIATION
Radiation is the direct transfer of energy by electromagnetic waves.
Radiation does not need any material to travel through!
Energy from the sun gets to us through radiation.

12. CONDUCTION
Conduction is the direct transfer of heat from one material to another that is touching it.
When a faster-moving molecule bumps into a slower-moving molecule, the slower one speeds up.
Conduction works best in solids.
Metal is a good conductor – the heat moves to the girl’s hand.
Wood is not a good conductor.

13. CONVECTION
Convection is the transfer of heat by the movement of particles in a fluid (liquid or gas).
As fluids heat up or cool down, their density changes. Lower-density materials will rise above higher-density materials.
MOVIE

14. HEAT TRANSFER

15. Cold air moves pretty slowly, and stays pretty tightly packed together:

16. Hot air, on the other hand, goes really fast and expands to fill more space.

17. So, hot air is LESS DENSE than cold air.

18. Spread out for low density
You should remember from our density column that less dense materials float on more dense materials.
Spread out for low density
Closely packed for high density

19. So, since hot air is less dense than the surrounding air, it rises, leaving a low-density, low-pressure area behind.
Low pressure

20. This rushing in of cold air is what we call… WIND!!
Nearby cold air can then rush in to fill low-pressure area left by the rising hot air.
This rushing in of cold air is what we call… WIND!!

21. UNEVEN HEATING
The uneven heating of the air that causes wind is created not only by different colors on Earth’s surface, but also by:
Different surfaces (grass vs. snow vs. water, etc.)
Pollution in some areas
Different amounts of sunlight due to seasons, clouds, etc.

22. During the day, the air over the sand is hotter than the air over the water because the water takes longer to heat up in the Sun.
So the wind in the daytime blows TOWARD the beach.

23. So the wind blows toward the ocean at night.
But at night, the air over the water is warmer than the air over the sand, because water HOLDS heat longer than the ground.
So the wind blows toward the ocean at night.

24. Sea Breeze

25. Land Breeze

26. Water in the atmosphere
It’s less obvious than surface water, but there are many signs of water in the atmosphere:
Rain, Snow, Drizzle
Clouds & Fog
Hot days that feel “muggy” or “humid”
Dew on the grass in the morning

27. Water Cycle
The movement of water between the atmosphere and earth’s surface is the water cycle.

28. How does water get into the air?
EVAPORATION – is the process where liquid water molecules escape into the air as water vapor.
3 things affect how quickly water evaporates:
1) Temperature
2) Wind
3) Humidity of the air

29. How much water can air hold?
HUMIDITY is the measure of how much water vapor is in the air.
TEMPERATURE affects how much water vapor the air can hold…
Warm Air
Cold Air
holds MORE water vapor.
holds LESS water vapor.
That’s why air feels more “HUMID” on hot days!

30. What is the “Dew Point”?
As air cools, the amount of water vapor it can hold decreases.
At a certain temperature, the water vapor in the air will CONDENSE back into water droplets or ice.
This temperature is the “DEW POINT”.

31. What are CLOUDS? They are made of tiny water droplets or ice crystals.
They form when water condenses onto small particles in the air (like dust).

32. How do clouds form?

33. Clouds are classified according to SHAPE
Flat clouds =
“Stratus”
Fluffy clouds =
“Cumulus”
Wispy clouds =
“Cirrus”

34. Clouds are also classified by ALTITUDE
HIGH LEVEL (cirro-)
MID LEVEL (alto-)
LOW LEVEL (stratus)