INTRODUCTION - FILL the blanks for full credits.
We are going to revisit the equation P = F/A. (P is for ________, F is for _______ and, A is for ________)
The unit for pressure is ___________-, unit for force is _____________, unit for area is ______________
The atmospheric pressure P is the weight F (weight is a force) of the air per unit area.
That is the pressure is the ratio ________ to _________.
(We suppose the atmospheric pressure to be the same at ground level. (it decreases with___________)
THat means that the weight F is the product of the __________ by the ________.
So if , for the same pressure, at ground level, you increases the area A, you increase the __________.
(use F = P A). We are going to demonstrate that.
PROCEDURE
MAterials: Newspapers, notebook paper, thin wooden slat, ruler in cm, hammer (or your thist)
Position a thin slat of wood such as a ruler or paint stirrer on a table so approximately 20cm hangs over the edge. Place 2 sheets of notebook paper on the slat and press against the table until the paper is as flat as posible. Strike the overhanging portion of the slat with a hammer, as shown by your instructor. Repeat this procedure using a large (double sheet) of unfold newspaper and record your results in the table provided. What is the magnitude of the force holding the slat down on the table in each case? (fill table, use F = P x A)
| Notebook Paper | Unfolded Newspaper | |
| Area of paper in cm2 (width by lendth) | ||
| Area of paper in m2 (you should know, 1m = 100cm but 1m2 = 10,000 cm2) | ||
| Atmospheric pressure | 101,300N/m2 (that is 10,000 kg/m2 or 14.7lbs/in2) | 101,300 N/m2 |
| Force upon pressure (force = pressure x area) | ||
| Does wood break? |
ANALYSIS (at home)
1) Is the air pressure on a sheet of notebook paper and the newspaper the same ? Is the force upon them the same ? Explain.
2) Did the wood break when placed under the notebook paper ? Whe nplaced under the newspaper ? Explian.
3) Realizing that air pressure is independent of surface area, why do large ships require large sails
(In the case, the wind is exerting a pressure on the sails, the pressure is the same but ..)
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vente par correspondence jeux éducatifs, jeux scientifiques clement o ni , jeux educatifs
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tub es a essai, apprendre l a nglais , coloriae , anglais maternelle, jeux clémentoni, cahiers maternelle, anglais enfants, anglais petits
vente par correspondence jeux éducatifs, jeux scientifiques clement o ni , jeux educatifs
Amina, Wanikou, mael r oi du mail , laboratoire chimie, fiches e xperiences, thomas au temps des chevaliers, Pilou la classe,
fichiers animation les francas, jeux engrenages singes, engre nages juniors, engr e nages train safari, prismes
microscopes, p rismes, jeux gyzmo sous la mer, jeux engrenages, c o loriage, travaux manuels, animaux, sciences, vente prismes
tub es a essai, apprendre l a nglais , coloriae , anglais maternelle, jeux clémentoni, cahiers maternelle, anglais enfants, anglais petits