INTRODUCTION - READ !! fill the blank for full credit
   area   -  15 - gravity  - force  -   1 -  F/A - pascal
Atmospheric pressure at sea level is about _____ kg/cm² (101.3 kPa or about ________lbs/in²). It this a large pressure or a small pressure ?. We are going to compare the magnitude of air pressure with something you are familiar with.. You will compare air pressure to the pressure a Physics book exert on the floor (or table). Since pressure is defined by the ratio_________  to _______ (p =________), The unit for pressure is _________. You can calculate the pressure an object exerts if we know its weight F (force of __________) and the surface area of contact A .

PROCEDURE
materials: small kitchen pan scale in kg, ruler in cm
You will need these conversion factors:
1 cm² = 0.0001 m²
1 lb = 0.454 kg
1 in² = 6.45 cm² = 0.000645 m²
1 Pa = 1.45 10^-4 lb/in²
1 kg mass  weighs 9.8 N

YOU NEED A PHYSICS BOOK, KITCHEN SCALE, RULER IN CM
Complete the table using the factors as needed (see above, solve proportions (fish))
You should be able to com plete the table on your own. Get a TI.

object	mass (g)	mass (kg)	contact area (cm2)	pressure in g/cm2	pressure  in kg / cm2
Physics textbook  (lying on front cover)	(use small scale)	(divide by 1000)	(width x length)	(divide mass in g/area in cm2)	(divide mass kg / area cm2)
atmospheric pressure (sea level)atmospheric	NA	NA	NA	1000g/cm2	1 kg/cm2
pressure (Mt everest)	NA	NA	NA	about 335 g/cm2	.335 kg/cm2

ANALYSIS

1) One Physics book exert more or less pressure than air on Earth ? (atmospheric pressure is due to the weight of air ) ?
How many of these books you need to pile up to match the atmospheric pressure at sea level ? (show work)
________________ books

How many books to match the pressure on Mt Everst ?  _________________ books

2) compare the pressure at sea level and on Mt everest.
(when you are asked to compare, you need to find the ratio betweem these 2 numbers). That is divide pressure at sea level by pressure on Mt everst.


3) why your ears pop when climbing a mountain?  (see the lesson question 1)

4) Airlines companies pressurize the cabins of aircraft so passengers do not experience rapid changes in air pressure. On a least one occasion, however, an airplane 's pressurization system failed and a passenger lost her hearing. Explain how the depressurization of the cabin may have caused this hearing loss.
(see question 3 for clues and think Eustachian tube and burst)

5) Why may it be painful to travel into the mountains if you have a head cold ?
(think Eustachian tube, question3)