Students will use a syringe and a pressure sensor to determine the relationship
between pressure and volume for air, a reasonable approximation of an ideal
gas (e.g. Boyle’s law, PV = constant).
Students will use a constant volume air pressure gauge to determine the
relationship between pressure and absolute temperature (e.g. Charles’
law, P/T = constant)
Students will use a constant volume air pressure gauge to determine the
Celsius temperature of absolute zero (e.g., the temperature at which pressure
would equal zero in a constant volume absolute air pressure gauge).
Students will use a fixed volume of air within a glass tube and, subjecting
it to a wide arrange of absolute temperatures, determine the relationship
between ambient temperature and volume (e.g. V/T = constant)
Students will integrate the results from objectives 4.1.1, 4.1.2, and 4.1.4
to derive the ideal gas law in the form PV/T = constant, and experimentally
verify.
4.2 Vapor Pressure
Students will identify the qualitative relationship between ambient pressure
and the boiling point of water.
Students will investigate the "negative" vapor pressure of condesning
steam by measuring the decrease in a certain volume of steam as it condenses
into water. Hint: Use the "fountain" created with the use of a steam-filled,
inverted Erlenmeyer flask (or similar) with a stopper and tube extending into
a beaker filled with water.
4.3 Fluid Pressure
Students will qualitatively analyze Pascal’s law with the use of a
Cartesian diver.
Students will derive a hypothetical law for the pressure at a point within
a fluid (P=rho*g*h).
Students will verify the above relationship with the use length of projected
water columns emitted from the side of a column of water (e.g., soft drink
bottle with a small hole in its side near the bottom.) Hint: Water must fall
far enough so that fluid column hits ground with vertical motion only. Compare
relative lengths of horizontal paths with expected relative pressures. This
experiment assumes that horizontal path length is associated with horizontal
speed, and horizontal speed with pressure at the point of ejection. One hole
in a bottle filled to different levels will provide the range of different
pressures and ensure that all other variables remain constant.
4.4 Fluids in Motion
Students will experimentally verify Torricelli’s theorem (v = sqrt(2gh))
using a 2-liter soft drink bottle, and an examination of water projected from
a bottle with one hole and filled to three different heights. (Hint: This
is a projectile problem.)
Students will use Newton's second law to theoretically explain pressure
in a fluid decreases as its speed increases.
Online Resources:
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Unit 4: Teaching Pressure