U3f – L2 March3, 2010 DRILL Using the chart of information you recorded yesterday, add two new columns onto your chart. Title one column “1/P” and calculate 1/P for each of the pressures in your chart (to 3rd decimal place). Title the second column “P x V” and calculate P x V for each of the volumes and pressures in your chart (to nearest whole number).

Principles of Fluid Technology U3f – L2 Principles of Fluid Technology Your chart should now look like this:

FLUID TECHNOLOGY What is a FLUID? U3f - L1 FLUID TECHNOLOGY What is a FLUID? A substance (as a liquid or a gas) that conforms to the outline of its container Fluid Systems have 2 things in common: They contain a fluid, either gas (pneumatics) or liquid (hydraulics) They contain a pressure difference that creates a net force

What is Fluid Technology? U3f - L1 REVIEW What is Fluid Technology? The technology of using fluid, either gas (pneumatics) or liquid (hydraulic) to apply force or to transport. Example applications: Air brakes on a truck, Tires on a car, Airfoils on an airplane, Warm-air heating ducts, Hydraulic jack, Plumbing in a school Hydro-electric dam

U3f - L1

Principles of Fluid Technology U3f - L1 Principles of Fluid Technology Graph your Volume and Pressure data Make volume the independent Make pressure the dependent Start both at zero X-axis Y-axis 60 55 50 45 40 35 30 25 20 15 10 5 What is the data range? Volume: 9-30 mL Pressure: 17-55 psi Pressure (psi) 0 5 10 15 20 25 30 Volume (mL)

Principles of Fluid Technology U3f - L1 Principles of Fluid Technology Your graph should like the graph below. What can you say about the relationship between volume and pressure? As volume increases, pressure decreases Is this a proportional or inversely proportional relationship? As Volume goes up, Pressure goes down As Pressure goes up, Volume goes down

Principles of Fluid Technology U3f - L1 Principles of Fluid Technology How is this represented mathematically? V 1 / P or P 1 / V Now graph Volume vs. 1/P Data range for volume is same; data range for 1/P is .018 to .058 Volume is independent 1/P is dependent [Volume is proportional to 1/P] a [Pressure is proportional to 1/V] a

Principles of Fluid Technology U3f - L1 Principles of Fluid Technology Is this representative of a proportional relationship?

Principles of Fluid Technology U3f – L2 Principles of Fluid Technology Back to your chart. What do you notice about the values for P x V? Under constant temperature, the product of pressure and volume for a fluid is a constant. P V = k

U3f – L2 Boyle’s Law Robert Boyle (1627-1691) – from Ireland, chemist, physicist, and inventor Boyle’s Law – the pressure and volume of an ideal gas are inversely proportional Increase Pressure Decrease Volume Increase Volume Decrease Pressure PV = k P1V1 = P2V2

U3f – L2 BOYLE’s LAW PV = k P1V1 = P2V2

Problems (copy these problems): U3f – L2 BOYLE’s LAW Problems (copy these problems): A gas system has initial pressure and volume of 60 psi and 8 L. If the volume changes to 5 L, what will the resultant pressure be in psi? A sample of helium gas is compressed from 200 cm3 to 0.240 cm3. Its pressure is now 3 psi. What was the original pressure of the helium? P1V1 = P2V2

#1 Solution: BOYLE’s LAW Does the answer make sense? U3f – L2 BOYLE’s LAW #1 Solution: Step 1: Write given information P1 = 60 psi V1 = 8 L P2 = ? V2 = 5 L Step 2: Write the formula and solve P1V1 = P2V2 (60 psi) x (8 L) = P2 x (5 L) 480 psi*L = P2 x (5L) 5L 5L P2 = 96 psi Does the answer make sense?

#2 Solution: BOYLE’s LAW Does the answer make sense? U3f – L2 BOYLE’s LAW #2 Solution: Step 1: Write given information P1 = ? V1 = 200 cm3 P2 = 3 psi V2 = 0.240 cm3 Step 2: Write the formula and solve P1V1 = P2V2 P1 x (200 cm3) = (3 psi) x (0.240 cm3) P1 x (200 cm3) = .72 psi*cm3 200 cm3 200 cm3 P1 = 0.0036 psi Does the answer make sense?