What is heat What is heat transfer?transfer?

The movement or passing of warmth

from one point (warmer) to another

(colder).

How does the Sun’s warmth How does the Sun’s warmth reach us?reach us?

Radiation is the Radiation is the method by which method by which the sun’s energy the sun’s energy reaches the earth.reaches the earth.

What type of ENERGY does the What type of ENERGY does the sun use to let the heat reach sun use to let the heat reach

us?us?Electromagnetic energy Electromagnetic energy (radiant energy). When (radiant energy). When the wave strikes you, it the wave strikes you, it becomes heat energy becomes heat energy again. again.

What can we do to “simulate” What can we do to “simulate” the sun’s heat and energy?the sun’s heat and energy?

How did you feel when How did you feel when your body was “protected: your body was “protected: from the sun’s energy?from the sun’s energy?

How did you feel when the How did you feel when the sun’s energy reached you?sun’s energy reached you?

Define Heat Transfer by Define Heat Transfer by Radiation Radiation

Energy from the sun (and a fireplace) Energy from the sun (and a fireplace) reach you by a type of HEAT reach you by a type of HEAT TRANSFER called RADIATION. In order TRANSFER called RADIATION. In order to travel through space, heat from to travel through space, heat from the sun must first be converted into the sun must first be converted into ELECTROMAGNETIC ENERGY (radiant ELECTROMAGNETIC ENERGY (radiant energy) which travels in WAVES. energy) which travels in WAVES. When the wave energy strikes you, it When the wave energy strikes you, it becomes heat energy again.becomes heat energy again.

The Electromagnetic The Electromagnetic SpectrumSpectrum

What is the electromagnetic What is the electromagnetic spectrum?spectrum?

The The electromagnetic (EM) spectrum is just a name is just a name that scientists give a bunch of types of that scientists give a bunch of types of radiation when they want to talk about them as a group. when they want to talk about them as a group.

Radiation is energy that travels and spreads out as Radiation is energy that travels and spreads out as it goes-- it goes-- visible light that comes from a lamp in your that comes from a lamp in your house and house and radio waves that come from a radio that come from a radio station are two types of electromagnetic radiation. station are two types of electromagnetic radiation. Other examples of EM radiation are Other examples of EM radiation are microwaves, , infrared and and ultraviolet light, light, X-rays and and gamma-rays. Hotter, more energetic objects and . Hotter, more energetic objects and events create higher energy radiation than cool events create higher energy radiation than cool objects. Only extremely hot objects or particles objects. Only extremely hot objects or particles moving at very high velocities can create high-moving at very high velocities can create high-energy radiation like X-rays and gamma-rays. energy radiation like X-rays and gamma-rays.

Radio WavesRadio Waves

Radio: Yes, this is the same kind of : Yes, this is the same kind of energy that radio stations emit into the energy that radio stations emit into the air for your boom box to capture and air for your boom box to capture and turn into your favorite Mozart, turn into your favorite Mozart, Madonna, or Justin Timberlake tunes. Madonna, or Justin Timberlake tunes. But radio waves are also emitted by But radio waves are also emitted by other things ... such as other things ... such as stars and gases and gases in space. You may not be able to dance in space. You may not be able to dance to what these objects emit, but you can to what these objects emit, but you can use it to learn what they are made of. use it to learn what they are made of.

MicrowavesMicrowaves

Microwaves: They will cook your : They will cook your popcorn in just a few minutes! popcorn in just a few minutes! Microwaves in space are used by Microwaves in space are used by astronomers to learn about the to learn about the structure of nearby galaxies, and our structure of nearby galaxies, and our own Milky Way! own Milky Way!

InfraredInfrared

Infrared: Our skin emits infrared : Our skin emits infrared light, which is why we can be seen in light, which is why we can be seen in the dark by someone using night the dark by someone using night vision goggles. In space, IR light vision goggles. In space, IR light maps the maps the dust between stars. between stars.

Visible LightVisible Light

Visible: Yes, this is the part that our : Yes, this is the part that our eyes see. Visible radiation is emitted eyes see. Visible radiation is emitted by everything from fireflies to light by everything from fireflies to light bulbs to stars ... also by fast-moving bulbs to stars ... also by fast-moving particles hitting other particles. particles hitting other particles.

ROY G BIV…. What’s that?ROY G BIV…. What’s that?

Ultraviolet WavesUltraviolet Waves

Ultraviolet: We know that the Sun is : We know that the Sun is a source of ultraviolet (or UV) a source of ultraviolet (or UV) radiation, because it is the UV rays radiation, because it is the UV rays that cause our skin to burn! Stars that cause our skin to burn! Stars and other "hot" objects in space emit and other "hot" objects in space emit UV radiation. UV radiation.

X-RaysX-Rays

X-rays: Your doctor uses them : Your doctor uses them to look at your bones and to look at your bones and your dentist to look at your your dentist to look at your teeth. Hot gases in the teeth. Hot gases in the Universe also emit X-rays . Universe also emit X-rays .

Gamma RayGamma Ray

Gamma-rays: Radioactive materials Gamma-rays: Radioactive materials (some natural and others made by man (some natural and others made by man in things like nuclear power plants) can in things like nuclear power plants) can emit gamma-rays. Big particle emit gamma-rays. Big particle accelerators that scientists use to help accelerators that scientists use to help them understand what matter is made them understand what matter is made of can sometimes generate gamma-of can sometimes generate gamma-rays. But the biggest gamma-ray rays. But the biggest gamma-ray generator of all is the Universe! It generator of all is the Universe! It makes gamma radiation in all kinds of makes gamma radiation in all kinds of ways. ways.

A Radio Wave is not a Gamma-A Radio Wave is not a Gamma-Ray, a Microwave is not an X-Ray, a Microwave is not an X-

ray ... or is it?ray ... or is it? Radio waves, visible light, X-rays, Radio waves, visible light, X-rays,

and all the other parts of the and all the other parts of the electromagnetic spectrum are electromagnetic spectrum are fundamentally the same thing, fundamentally the same thing, electromagnetic radiation. electromagnetic radiation.

What are electromagnetic What are electromagnetic waves?waves?

Electromagnetic waves are formed when an electric field (shown as blue arrows) couples with a magnetic field (shown as red arrows).

Magnetism can also be static like a refrigerator magnet. But when they change or move together, they make waves - electromagnetic waves.

What are electromagnetic waves?Electricity can be static, like what holds a balloon to the wall or makes your hair stand on end.