Vocabulary

Career Connections

An

aerospace engineer

designs machines that can fly, including aircraft, spacecraft,

satellites, and missiles. Most aerospace engineers work for the aircraft industry or

government agencies, such as the National Aeronautics and Space Administration (NASA)

or national defense agencies.

A

computer programmer

designs, writes (i.e., codes), and troubleshoots computer programs

(also known as software). Computer programmers can work in almost any industry.

A

materials scientist

studies the physical and chemical structure and properties of different

materials, such as metals, plastics, glass, ceramics, and textiles. They research ways to

improve materials or create new materials. Materials scientists usually work in a laboratory

and can find work in many different industries where products are made.

• conduction • insulate/insulator • spacecraft bus

• conductor • radiation • stable

• convection • satellite • thermal energy

• external housing • space travel

Students should understand that there are three primary methods of heat transfer (TEKS

6(9)(A)).

Conduction

occurs when thermal energy (heat) is transferred though direct

contact, such as a pot of water on an electric stove burner. Another type of heat transfer

is called

convection

that occurs as a gas or liquid moves when heated. When gases

or liquids are heated, the warm particles spread out, become less dense, and rise. The

particles cool as they move away from the heat source, becoming denser, and begin to

sink. This cycle of moving particles is called a convection current. The third method of heat

transfer is

radiation

where heat is transferred by waves. Heat from the Sun is transferred

to Earth via radiation. In fact, radiation is the only way heat can travel through space.

Radiation occurs on Earth as well. Any time you feel heat without touching the source,

such as warming your hands by a fire or sitting in sunshine, you experience radiation.

Students should also understand thermal energy moves in a predictable pattern from

warmer to cooler until all of the substances attain the same temperature (TEKS 6(9)(B)).

When a satellite is in low-Earth orbit and not protected by Earth’s atmosphere, its surface

temperature can get high when exposed to heat that radiates from the Sun. Once that heat

is transferred from the Sun to the external surface of the satellite, thermal energy may be

transferred to the internal parts of the satellite due to conduction. For example, the exterior

surface of the International Space Station (ISS) would reach 120°C (250°F) when facing the

Sun if thermal controls were not present (NASA, 2001). If the internal parts of the satellite

get too hot, they could stop functioning.

Conversely, when the satellite passes behind the Earth or Moon, it is not exposed to radiation

from the Sun and the external temperature of the satellite can drop low. As an example, the

exterior of the ISS would reach -150°C (-250°F) without thermal controls (NASA, 2001). When

satellites are out of direct sunlight, the internal temperature of the satellite may fall as heat is

transferred from the warmer interior of the satellite to its colder exterior.

Teacher Notes

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