Guide to Propulsion
Gas Properties Definitions
Answers will vary. Suggested answers are shown below:
1. What is the
meaning of the term micro? small scale, molecular
2. What is
the meaning of the term macro? large scale,
3. In terms
of observation, what is the difference between micro and macro? macro
scale is based on things observed and measured; micro is based on theories,
not direct observation
air is treated as a uniform gas, its major component is nitrogen
5. Why doesn't
a gas have a fixed shape or size? Because
molecules are free to move about, they fill any container, regardless
of shape or size.
6. Which theory
is used to describe the behavior of gases? kinetic
theory of gases
7. What does
the theory above assume about the size of gas molecules? The
size of the gas molecules is very small compared to the distance between
8. What does
the theory assume about the motion of gas molecules?
motion of gas molecules is constant and random.
9. A gas is
an example of a fluid. What other state of matter is an example of a fluid?
Liquids are also fluids.
two beakers and fill them with water. Carefully add a dropper of dye or
food coloring to the top of the water. Describe the process you observe:
The dye starts to move through the beaker
of water, spreading out, becoming more diluted.
11. What is
the name of the process you observed? diffusion
squirt a dropper of dye or food color into the second beaker of water
and describe the process you observe. The
dye moves in the direction that it was squirted into the water; it flows
in that direction, away from the dropper.
13. Why did
the dye move differently the second time? A
force was added from the dropper.
14. If you
now stir the dye around in a circular motion in the beaker, you should
see rotational motion.
15. What is
16. What is
a boundary layer? a layer of air near a surface
which, in effect, changes the shape of an object, such as an airplane
17. Which scientist
introduced the concept of boundary
18. This discovery
is the greatest discovery in the field of fluid
19. Air viscosity
and boundary layer are important in flight because they affect which two
forces involved in flight? lift and drag
20. At high
speeds, the air is compressed during flight. What happens to the density
of the air? When air is compressed, its density
increases because the same mass of air is pressed into a smaller volume.