Trapped Inside - Data Sheet



Mass of jar lid: ______________ g

Mass of inflated ball and lid: ____________ g

Radius of the ball: _____________ g

Mass of partially deflated ball and lid: ___________ g


Mass of the escaped air:
(Mass inflated ball - Mass paritally delfated ball)


Volume of air inside the ball:
(V = (4/3)pi*R^3)


Denisty of the air at normal pressure:
( Density = Mass of air/ Volume of air)



* You can find the density of air at normal pressure because a ball inflated to regular game pressure is at about twice the pressure of regular outside air (measured as one atmosphere). Thus, when you let out the "extra" air in letting the ball deflate to standard room air pressure, you are letting out about half of the air, or one atmosphere's worth.

Answer the following questions on a seperate sheet of paper:

What is inside the ball? What does the mass measurement include?

Does the soccer maintain a constant volume as air is added to it?

As the ball was being inflated, what was "pushing" on the sides of the ball?

Did the mass of the ball change as it was inflated? What do you think caused the change in mass?

Define matter. Based on the properties of air you have observed in this experiment, what can you conclude about air in relation to the criteria for being matter?

The accepted value for the density of air is about 1.3 g/L, or .0013 g/cm^3. How close was your measurement of the denisty? What may have caused the difference between your answer and the accepted value?