Fluid Principles

Fluid Principles Bernoulli’s Principle - Lucas Kraschnewski Howard, WI ECOMP 5016 Properties of Fluids Pascal’s Principle Archimedes’ Principle Click here to view additional PowerPoint after successful completion of this one!

Properties of Fluids • Introduction to Fluids • Properties of All Fluids: • Direction of Flow • Pressure • Expansion Principles

Properties of Fluids SORRY! Liquids are Fluids • Introduction to Fluids A fluid is any material that flows and its shape changes to that of its container. Click on the picture that is not a fluid CORRECT! Dirt and all other solids are NOT fluids SORRY! Gases are Fluids Start: Section 1

Properties of Fluids • Direction of Flow In what direction do all fluids flow, no matter if they are liquids or gases? This can be illustrated with balloons as well. There is more pressure inside the balloon and as a result, if the balloons were to be untied, all the air would shoot out! The muscle (red) pushes up on the lungs and air goes out the mouth. There is less pressure outside the mouth than in the lungs that are getting squeezed by the muscle • Top to bottom (downward) B. Bottom to top (upward) C. High Pressure to Low Pressure D. Low Pressure to High Pressure Start: Section 1

Properties of Fluids • Pressure …the amount of force exerted on a given area (Pressure = Force / Area) • You can increase pressure 2 ways: • Push harder (more force) • Push with the same force but on a smaller area Who is applying more pressure? A man pushing on a 2 square meter box with a force of 4,000 N A woman pushing on a 4 square meter box with a force of 4,000 N or Start: Section 1

Properties of Fluids • Expansion Principles It possible to blow bubbles that are square. True Balloons and bubbles are always round because fluids expand with equal force in all directions False Force Start: Section 1

Bernoulli's Principle • Introduction • Applications of Principle to: • Airplanes • The Game of Baseball • Golf • Race Cars • Other Examples….

Bernoulli's Principle • Introduction As the speed of a fluid increases, the pressure decreases Start: Section 2

Bernoulli's Principle • Airplanes Given the same size plane, which wing design would allow a plane to get off the ground the fastest? Click on airplane to see side-views of the wings Since the air going under the wing is going slower, there is more pressure beneath the wing and this pressure lifts the plane off the ground! As air hits the front of the wing, it splits. Some flows over the top & some flows underneath. The air going over the wing has to travel a longer distance, due to the shape of the wing, so it travels faster. All the air comes off the back of the wing at the same time! *Air* INCORRECT!!! Correct!!! Click to see why? Start: Section 2

Bernoulli's Principle • The Game of Baseball What makes the ball curve when a pitcher throws it? Since the air is moving faster below the ball, where is there more pressure on the ball? THINK: Where is the air moving faster? Above or Below the ball? The ball is spinning when it’s thrown (In this case, it’s spinning COUNTER-CLOCKWISE) Slower Moving Fluid = Higher Pressure So…. There is more pressure pushing down on the top of the ball because the air is moving slower there!! Air is moving faster below the ball because the ball is spinning in the same direction the air is flowing Click baseball for more info. Which way will the ball curve? Up or Down? Start: Section 2

Bernoulli's Principle • Golf It’s all about the DIMPLES!! Why do golf balls fly so far through the air? *Air* Faster Moving Air = Less Pressure Basically, an area of low pressure surrounds the spinning ball and since there is less pressure on the ball, it travels a longer distance As the spinning ball travels through the air, some air dips in-and-out of the dimples, while some air goes between the dimples The air that goes in-and-out of the dimples has to travel farther, so it has to travel faster as well Click for close-up view Start: Section 2

Click to learn more Bernoulli's Principle • Race Cars A spoiler is just an upside down wing. Air must go farther underneath, so it must go faster as well, in order to come off the back of the wing at the same time. This increased downward pressure holds the back tires on the ground for better traction. The air goes slower over the top of the spoiler, so there’s more pressure above the spoiler. Why do race cars have spoilers on rear of the car? SORRY! A. To make the car more aerodynamic An airplane wing (side view) B. To relieve some pressure pushing down on the back tires SORRY! C. To add some pressure pushing down on the back tires Correct!! D. To slow the car down SORRY! A spoiler (side view) *Look at picture above Start: Section 2

Bernoulli's Principle • Other Examples…. Try these 3 activities on your own at home or school Print the Activities 1 and 2 Worksheets off from the links provided below and complete before turning in Activity #1 Hold 2 sheets of computer paper out in front of your mouth, 1 on each side of your face about 4-6 inches apart and then blow hard between them Activity #2 Tie a string to a ping pong ball. Turn a faucet on high and hold the ball by the end of the attached string in the running water Activity #3 Select and complete one of the projects discussed at this link. Click to open and print off this sheet for your project Start: Section 2

Pascal's Principle • Introduction • Applications of Principle to: • Hydraulics • Hydraulic Brakes

Pascal's Principle • Introduction A change in pressure at any point in an enclosed fluid will be transmitted equally to all parts of that fluid Start: Section 3

Pascal's Principle • Hydraulics …hydraulics are devices that use liquids to transmit pressure from one place to another. * They use liquids because they can’t be compressed, squeezed into a smaller space. The pressure is passed through the water line equally in all directions and all the way along it. Question #1: Where will the water pressure increase more if the water pumping station increases the pressure by 20 Pascal. At the supermarket 1 block away or your house 1 mile away? Both Places Start: Section 3

Pascal's Principle • Hydraulic Brakes How do they work? Liquids are used in hydraulics and not gases, because no matter how much pressure is in that tiny hydraulic line, the liquid will not compress. It moves straight ahead and pushes the break pad against the wheel Because the line is so small, and so much liquid is being forced through it, the liquid has tremendous pressure behind it You push your foot gently on the brake pedal, which is connected to a very small and easy-to-move piston This tremendous liquid pressure is then exerted on the brake pad which moves up against the wheel, and stops it from turning The small piston gets pushed forward causing a much larger piston to move as well, which forces liquid into a tiny hydraulic line Large Piston Small Piston Tank of Hydraulic Fluid Brake Pedal Brake Pad Hydraulic Line Start: Section 3

Archimedes' Principle • Introduction • What is Buoyancy? & The Science Behind Floating Objects! • Applications of Principle to: • Large Floating Vessels • Submarines

Archimedes' Principle • Introduction The buoyant force on an object in a fluid is an upward force equal to the weight of the volume of fluid that object displaces Start: Section 4

Archimedes' Principle • What is Buoyancy? & The Science Behind Floating Objects! If you put the 2 objects below in a bowl of water, which will make the water level rise more? The Duck Floats & The Rock Sinks * The rock is bigger so it has more buoyant force holding it up, yet it sinks. Why? ….because the science of floating involves buoyant force & WEIGHT!! * Analyze the numbers. See if you can determine why the rock sinks. * Buoyancy is the upward force that fluids exert on objects, which aids in making the objects float You may be thinking, that doesn’t make sense, because we all know big objects usually sink? Click to learn more! Weight of Duck = 10 N Weight of Water Displaced = 15 N Weight of Rock = 40 N Weight of Water Displaced = 30 N The amount of upward force holding the object up depends on how much water the object displaces (how much water level rises) THINK ABOUT IT THIS WAY: The more water the object displaces, the more upward (buoyant force) there is pushing up on the bottom of the object …because the large gold box will displace more water, it will have more buoyant force pushing up on it. The buoyant force pushing up on the rock is only 30 N because that is how much water was displaced by it. The rock weighs 40 N. 30 N of force isn’t enough to hold up a 40 N object! INCORRECT CORRECT Start: Section 4

Archimedes' Principle • Large Floating Vessels The heavier the ship, the larger in size it must be, so that it displaces more water. The water it displaces must weigh more than the ship itself, so that the buoyant force is strong enough to hold the ship up. If it doesn’t displace enough water, the ship will sink. A ship is extremely heavy, but yet they float? Ships are also very large in size! Why is that important? A. Ships displace a lot of water Almost! B. The weight is spread out over a larger area (Less Dense) Not Quite! C. Both A & B Start: Section 4

Archimedes' Principle • Submarines A submarine has tanks that can fill up with water to make it heavier so it sinks. In the case below the submarine would have to fill the tanks with 1,001 N of water or more to sink! Things such as: submarines, humans, and fish can float and sink. How is this possible? A submarine is hollow on the inside for the most part. (It is not very dense – the weight is spread over a large area) It will float because the buoyant force (displaced amount) is more than the weight of the submarine! What does a submarine do to make itself sink? Which variable below can it change? The submarine can’t shrink up so it displaces less water. But it can increase in weight!! ** Example ** Weight of Submarine = 20,000 N Weight of Displaced Water = 21,000 N Size of Submarine = 2,000 cubic feet Will the submarine float? Start: Section 4

References Content: Holt, Rinehart, & Winston,. (2002) Forces, motion, and energy. Eureka! A bat with dimples. (p. 58). Austin, TX: Harcourt Classroom Education Co. Holt, Rinehart, & Winston,. (2002) Forces, motion, and energy. Forces in fluids (pp. 68-81). Austin, TX: Harcourt Classroom Education Co. Science Standards (Grade 8): D.8.5While conducting investigations, explain the motion of objects by describing the forces acting on them D.8.6 While conducting investigations, explain the motion of objects using concepts of speed, velocity, acceleration, friction, momentum, and changes over time, among others, and apply these concepts and explanations to real life situations outside of the classroom

References Sound / Images: Callaway Golf Co. (2005). Retrieved November 12, 2005, from http://www.callawaygolf.com/en/default.aspx Fogerty, J. (2005). Centerfield. The Long Road Home [CD]. Beverly Hills: Concord Music Group. Indy Racing League. (2005). Indycar series. Retrieved November 12, 2005, from http://indyracing.com/home.php Mitchell, M,. (2003). Animated demonstration of Bernoulli’s principle. Retrieved November 12, 2005, from http://home.earthlink.net/~mmc1919/venturi.html Rawlings Corp. (n.d.). Retrieved November 12, 2005, from http://www.rawlings.com/ Rolling Greens Stock Agency & Golf Photography. (1998). Retrieved November 12, 2005, from http://www.rollinggreens.com/ Default.htm Storm, R,. (n.d.). Glenn Learning Technologies Project: Ping pong ball curves. Retrieved November 12, 2005, from http://www.grc.nasa.gov/ WWW/K-12/TRC/ Aeronautics/ Ping_Pong_Curve.html The Boeing Company. (n.d.). Retrieved November 12, 2005, from http://www.boeing.com/flash.html

Fluid Principles