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What do the changes in

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locations of ocean life

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and astronaut underwear have in common?

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Well,

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it has to do

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with thermal energy transfer.

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Stick around to learn more.

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Hi.

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I'm NASA astronaut, Loral O'Hara, and I'm

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living and working

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aboard the International Space Station.

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Today, we're talking about thermal energy

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or heat.

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All living things,

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whether living in the oceans or in orbit

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need to be within

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a special thermal balance

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within their environment to live.

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We call this balance homeostasis.

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Too hot or too cold, we won't survive.

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Luckily, there are three different ways

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that thermal energy

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can be transferred from place to place

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to help maintain homeostasis:

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convection, convection and radiation.

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Conduction is how thermal energy

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is transferred from one object

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to another through direct contact.

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When you swim in the cool ocean

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thermal energy from your body

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is connected directly to the water.

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That loss of

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thermal energy is felt

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as a cold sensation.

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Ocean life maintains

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homeostasis by living in water

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that is the correct temperature

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they need to survive.

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Astronauts aboard the space station

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can even track this by making direct

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observations of large ocean

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life such as coral reefs

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and blooms of algae.

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To stay in homeostasis

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during spacewalks, astronauts

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wear special garments

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under their spacesuits,

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called a liquid cooling

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and ventilation garment or LCVG.

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This full body garment with small

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tubing sewn into the fabric

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is worn close to our skin.

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Cool water is packed through the garment,

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which helps to conduct heat

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away from the astronaut

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as we perform spacewalks

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in the harsh environment of space.

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Similar technology is being increasingly

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used on earth

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when open air cooling is difficult,

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such as for firefighters,

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steel mill workers and surgeons

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during long procedures.

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The next method of

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thermal energy transfer,

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convection, only applies to fluids

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like air and water.

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When the temperature of a fluid changes,

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its density changes as well.

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This will cause large amounts

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of a cooler fluid to sink

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because it is denser

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than the warmer fluid surrounding it.

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In oceans, the convection of warm water

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rising near the equator

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and sinking of cooler water

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near the poles

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feeds oceanic currents

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that circulate the ocean water

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all over the world.

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This aids in the migration of sea

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life as they ride these currents

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and stay within channels of water

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at certain temperatures

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to maintain homeostasis.

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However, this is not the case

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on the orbiting laboratory.

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In microgravity,

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the density of an object

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does not affect its motion.

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So a pocket of warm air

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created by computers,

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a warmed up meal or even our body heat

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just kind of stays there.

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That's why

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we use a series of fans

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and ducts

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to mix and circulate

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the air on space station

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to keep us in homeostasis.

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The final method of

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thermal energy transfer,

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radiation, is vital for our oceans

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and the space station.

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Radiant energy

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from the Sun

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in the form of visible

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and UV light is absorbed

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by the oceans during the day

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and is converted to thermal energy,

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warming the water.

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Thermal energy

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is also radiated away from the ocean

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in the form of infrared light.

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This energy radiated

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from the oceans, warms

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our atmosphere and cools

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oceanic temperatures,

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keeping them both stable.

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The temperature on space

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station is regulated through radiation.

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The space station is outfitted

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with large radiators,

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which have a large surface

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area of panels to radiate away

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the excess thermal energy of station,

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keeping the station

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in a type of homeostasis.

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Maintaining the right temperature

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using thermal energy

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transfer is a big job,

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both aboard the space station

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and in our oceans.

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What methods

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are you using to stay in

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thermal homeostasis right now?

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Convection?

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Convection? Radiation?

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All three?

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Share your observations

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as you work on the corresponding

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classroom connection.

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Thank you for exploring thermal energy

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transfer with me today.

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See you next time!