Air in Motion
Problem
What will happen when
four different kinds of balls are put into a vertical flow of fast-moving
air?
Suggested Materials
variable-speed
hair dryer
balloon inflated
to about 15 cm
table tennis ball
hollow-centered
rubber or plastic ball 3-to 4 cm in diameter golf ball
Safety
Keep your hands away
from the hair dryer's exhaust opening as it will get hot. Do not
use the dryer near water. Do not throw or drop golf balls.
Devise a Plan
1. For each of
the four objects, write a hypothesis about what will happen when the object
is put into the fast-moving vertical flow of air from the hair dryer.
2. Decide exactly
how you will test your hypothesis. Write down your plan.
3. Carry out your
plan and record your results.
Analyze and Conclude
After following the plan
you devised, answer the following question.
1. What happened?
Were your hypotheses proven correct? Did you speed of the airflow
makes a difference?
2. Use your knowledge
of fluids in motion to explain your observations. What forces were
involved in this experiment? Were they balanced or unbalanced?
3. Does Pascal's
principle apply in your experiment? Why or why not?
4. Rank the objects
according to their densities. Make rough estimates of their densities
compared to the density of water. Which do you think would float
on the surface? Which ones would sink?
In assessing your performance, I will be
the rubric designed
for Air in Motion