The environment where astronauts float in the International Space Station

is an example of microgravity. Microgravity is a condition where some of

the effects of gravity are reduced compared to those experienced on

Earth. As mentioned previously, astronauts and the Space Station are

actually in a state of free fall around Earth.

Creating Microgravity

There are various ways to create microgravity. As mentioned before, one

way to create microgravity is to put an object in a state of free fall.

Researchers have devised facilities that use free fall to create

microgravity conditions for varying lengths of time. These include drop

facilities, parabolic aircraft, sounding rockets, and orbiting spacecraft.

Another way to achieve microgravity is by sending a spacecraft far into

space to escape Earth's gravitational pull. To reach a point where Earth's

gravity is reduced to one-millionth of that on Earth's surface, the

spacecraft would have to travel almost 17 times farther away than the

Moon (6.37 million km)! Such travel is not a practical alternative.

Microgravity Research Environment

Microgravity is a useful research environment because it reduces the

effect gravity has on convection and sedimentation. These processes

affect fluids and the way materials solidify. Microgravity provides a new

research environment so scientists can study a wide range of phenomena.

On Earth, buoyancy-driven convection occurs when less dense fluids rise

and denser fluids sink. Boiling water on a stove is a common example of

such convection. As water at the bottom of a pot heats, small bubbles of

gas form that are less dense, and rise to the top. At the same time, cooler,

denser water replaces the bubbles at the bottom, causing a flow pattern.

Similarly, during combustion hot, less dense products of a flame rise, and

cooler, denser surrounding air sinks to the flame's base, creating similar

flow patterns. In microgravity, buoyancy-driven convection is reduced,

causing a candle flame to appear rounder and dimmer.

Sedimentation occurs when fluids and particles of different densities form

layers, with denser layers at the bottom. Italian salad dressing is a

common example of sedimentation. However, in microgravity, fluids with

different densities do not settle out. For example, water traveling through

a pipe could contain pockets of air, instead of water being on the bottom

and air staying on top.

Microgravity: Fall into Mathematics

Microgravity

Microgravity is an

environment or condition

where some of the effects of

gravity are reduced

compared to those

experienced on Earth.

Hot air rises.

Cool air sinks.

Candle in 1 g

Candle in microgravity

No convection

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