Do NOW If a cup of coffee and

Do NOW: If a cup of coffee and a red popsicle were left on the table in this room what would happen to them? Why? Hmmmm….

Answer n The cup of coffee will cool until it reaches room temperature. The popsicle will melt and then the liquid will warm to room temperature.

Ms Aeschlimann’s 6 th Grade Earth Science

Here is how it works: n n n Heat Energy IS THE MOVEMENT OF PARTICLES. It is what makes the coffee hot and the room warm. Since the room has a lower temperature than the coffee, heat energy travels from the coffee to the room. The opposite happens to the popsicle. The room is warmer than the popsicle. So heat energy travels from the room to the popsicle, first melting it and then warming the liquid to room temperature. Heat energy always moves from HOT to COLD !

Now that we know which way heat energy travels (from hot to cold), how does it actually travel? There are three types of heat transfer: CONDUCTION • CONVECTION • RADIATION •

Conduction n n Conduction is transfer of heat through direct contact. This is how heat is transferred to your finger if you touch a hot stove!

Conduction When you heat a metal strip at one end, the heat travels to the other end. As you heat the metal, the particles vibrate, these vibrations make the adjacent particles vibrate, and so on, the vibrations are passed along the metal and so is the heat. We call this? Conduction

Convection n When fluids (liquids and gases) are heated, currents are created. An example of this can be observed in the air currents that are created in a room with a radiator against one wall. The air in contact with the radiator rises, moves across the ceiling to the far wall, sinks, and then comes back to the radiator across the floor.

Water movement Cools at the surface Cooler water sinks Convection current Hot water rises

Why is it windy at the seaside?

Joke Break

Radiation n n Radiated heat energy travels through empty space. Electromagnetic waves travel at the speed of light, which is 300, 000 meters per second. Sometimes these waves are visible, like when something is “red hot. ” You can see how hot it is, but you can also feel it from a distance, as your skin absorbs the energy. Question: Do you think that radiated heat needs a material to travel through like heat transferred by conduction or convection?

NO! n n Electromagnetic waves do not need a material to travel through, although they can travel through many substances. If this wasn’t true, we wouldn’t feel the heat of the Sun here on Earth!

The third method of heat transfer How does heat energy get from the Sun to the Earth? ? There are no particles between the Sun and the Earth so it CANNOT travel by conduction or by convection. RADIATION

Q. ) When you put a teapot on the stove to boil water, which of the three (3) kinds of heat transfer can be observed? Actually, all three! Here is how…

Conduction First, there is Conduction between the burner and the teapot, and then Conduction between the teapot and the water molecules that are in direct contact with the teapot.

Convection Next, there is convection in the water as the heated molecules of water from the bottom of the teapot rise and spread their heat energy to the cooler molecules above them through direct contact. This convection current also pushes cooler molecules of water down to the bottom where they come in contact with the heated bottom of the teapot.

Radiation While all of this is occurring, heat energy is being radiated in all directions from the burner and is absorbed by other objects. You can feel this energy if you stand too close!

Conduction, Convection and Radiation

HOMEWORK n FIND 3 EXAMPLES OF CONDUCTION, CONVECTION AND RADIATION AT HOME AND WRITE THEM DOWN.