Day 1: Fluids Under Pressure

1. Day 1: Fluids Under Pressure CHAPTER 9 KEY QUESTION: How do pressurized fluids affect our lives and the lives of other living things? Looking Ahead Under pressure, some fluids behave differently than others. The skills of scientific inquiry can be used to study how fluids are used in hydraulic systems and pneumatic systems. Fluids are used in systems to accomplish tasks. Pressurized fluid systems occur in nature as well as in human-made devices. Technological problem solving skills can be used to create a working model of a hydraulic or pneumatic device. Human use of fluids technology has social and environmental costs and benefits.

2. 9.1 Putting the Squeeze on Fluids • Liquids are much more difficult to compress than gases. Thus liquids have much less compressibility than gases. • Pneumatic systems use pressurized gases (often air) to do work. For example: a pneumatic jack-hammer. • Hydraulic systems use pressurized liquids (often oil) to do work. For example: a tractor • Each hydraulic and pneumatic system have the following components: • A pump (to move the fluid) • Conductors (to carry the fluid) • Valves (to keep the fluid moving in the desired direction) • Pressure gauge (to monitor the pressure) compress pneumatic system hydraulic system

3. CHAPTER 9 Fluids Under Pressure — Activity • Pressurized fluids are used everyday in a variety of things. • Think of two hydraulic systems, and two pneumatic systems. • For each system, identify the pump, conductor, and use of the pressurized fluid.

4. Day 2: Lab Reports for Grade 8 **p.362-363** • 1. Title • 2. Testable Question – List questions you are trying to answer • 3. Hypothesis – Your prediction • 4. Equipment List • 5. Procedure – Point form steps • 6. Data and Observations – Use a table or graph • 7. * Analysis and Evaluation – Questions from text • 8. * Apply & Extend

5. 9.2 Conduct an InvestigationInvestigating Fluids in a Closed System Today: Complete Investigation p.230/1 Discuss success criteria for a LAB REPORT Begin report. Complete LAB REPORT due on Friday at the beginning of class. Pressurized fluids in both hydraulic and pneumatic systems are used to do work. In this activity, you will compare work done by these two types of systems. Purpose To compare the effect of using hydraulic and pneumatic systems to move a load. Equipment and Materials

6. Day 3: Effects of External Pressure on Fluids Vocabulary • Pressure: The FORCE per unit of area. We use the unit of Newtons for force • P = Force/Unit of Area ex: 1 N/m2 • Pascal (Pa): The unit of measurement for pressure. • 1 Pa = 1 N/m2 • Atmospheric Pressure: The force the atmosphere exerts on a unit of surface area. • Pascal’s Law: A force applied to a fluid is distributed evenly through all parts of the fluid.

7. 9.4 • Pressure refers to the force applied to a unit of surface area.i.e. pressure (p) = force/unit area • Atmospheric pressure, or air pressure, is the force exerted by the atmosphere on a unit of surface area. • Atmospheric pressure decreases the higher you ascend, because there is less air above you pressing down. • Pascal’s Law states that a force applied to a fluid is distributed equally through all parts of the fluid.It is this ability of fluids to transfer force that make them useful in nature and machines. • Recall: Pressure is measured in Pascals where: • 1 Pa = 1 N/m2

8. CYL • P.229 #1,2,3 • P.236 #1,2,3,4 PSI – Pounds of force per square inch. One pound per square inch approximately equals 6894.757

9. 9.5 Day 4: Relationships: Pressure, Volume, and Temperature • When a gas is under pressure (in a closed system), its volume is decreased. • Liquids under pressure also have a decreased volume, but it is so small it is not noticeable. • The more a gas is compressed into a small volume, the more collisions that occur between gas particles and the walls of the container. This means the pressure is greater. • As temperature increases, the particles of a fluid move faster and farther apart. This causes the fluid to increase in volume (expand). If temperature drops, a fluid’s volume decreases (contracts).E.g. thermometers.

10. Learning Task… • Use your knowledge of pressure, temperature and volume to explain how a mercury thermometer works • Mercury freezes at -39degrees and boils at 357degrees. Use this to explain why it is used in thermometers. • Can anyone think of why a propane bottle gets frost when you use it? Or why windows get frost on the inside in the winter?

11. 9.7 Day 5: The Value of Valves • Valvesare devices that control the movement of a fluid through a hollow tube or pipe. • Example: Your circulatory system uses valves: • Your heart uses valves to pump blood in one direction. • Your veins use valves to prevent blood from backing up or pooling. • Human-built systems also use valves to ensure fluids go in the desired direction, such as in an internal combustion engine. valve internal combustion engine

14. 9.8 The Power of Fluids • We use pressurized fluids every day to increase the amount of work we can do. • Hydraulic rams are used in excavators, backhoes, and front-end loaders because they can move in and out with tremendous force and great precision. • Fire pumps and hoses use hydraulic power to project water or foam a long distance. • Hover crafts use pneumatic power to ride on a cushion of air over land or water. • Kneeling buses use pneumatic power to make it easier for many people to access public transportation. • Some machines use combination systems that use both hydraulic and pneumatic power, such as with automobile hoists.

15. Open your texts…243

16. 9.9 Explore an Issue CriticallyPutting Fluids to Work The Issue Select one example of fluid technology and use it to support or refute the state below: The benefits of using this form of fluid technology outweigh the costs. Also, identify individual actions that could help alleviate some of the costs, or enhance the benefits, of the technology you have chosen Communicate The results of your research and your decisions must be communicated effectively and concisely in an interesting manner to your classmates and others in your school. You may choose to create a poster, brochure, or computer presentation.

17. CHAPTER 9 Summary – Looking Back • Under pressure, some fluids behave differently than others. • Pressure is a measure of the force per unit area. • Gases are more compressible than liquids. • The particle theory of matter explains the different behaviour of gases and liquids under pressure. • There are strong relationships between the temperature, pressure, and volume of a fluid. • Systems use fluids to accomplish tasks. • Hydraulic systems use pressurized liquids to perform tasks. • Pneumatic systems use pressurized gases to perform tasks. • Valves allow us to use hydraulic and pneumatic systems in controlled ways.

18. CHAPTER 9 Summary – Looking Back • The skills of scientific inquiry can be used to study how fluids are used in hydraulic systems and pneumatic systems. • Hydraulic and pneumatic systems can be created using syringes, tubing, water and air. • Applications of Pascal’s Law can be modelled using syringes, tubing, water and air. • The ability of hydraulic and pneumatic systems to move a load can be observed using syringes, tubing, water, and air. • Pressurized fluid systems occur in nature as well as in human-made devices. • Atmospheric pressure is exerted by the weight of the atmosphere. • Water pressure increases with depth due to the weight of the water. • Pressure applied to a fluid is distributed evenly throughout all parts of the fluid.

19. CHAPTER 9 Summary – Looking Back • Technological problem solving skills can be used to create a working model of a hydraulic or pneumatic device. • Everyday materials and a knowledge of Pascal’s Law can be used to design, build, and test a working model of an everyday object that operates using hydraulics or pneumatics. • Human use of fluids technology has social and environmental costs and benefits. • We use pressurized fluids to make our lives more manageable and to increase the amount of work that humans can do. • We use pressurized fluids at home, at work, and at play. • Our use of hydraulic and pneumatic systems allows us to make major changes to society and the environment. • Our ability to make such changes must be accompanied by a commitment to make these choices responsibly.

20. CHAPTER 9 Quiz Multiple choiceFor each question, select the best answer from the four alternatives. • A system that uses compressed air (or another gas) to do work is called a… • Hydraulic system. • Low pressure system. • Pneumatic system. • Open system. • What happens when a fluid is under pressure? • It contracts. • It expands. • It cools. • Pressure decreases. • If a gas exerts 8 N of force over a 2 m2 area, what is the pressure on that area in N/m2? • 10. • 6. • 4. • 16.

21. CHAPTER 9 Quiz True/FalseIndicate whether each of the statements is TRUE or FALSE. If you think the statement is false, rewrite it to make it true. • Liquids are more compressible than gases. • Compressing a fluid will decrease its volume. • Cooling a fluid will decrease its volume. • Valves control the movement of fluid through a tube or pipe.

22. CHAPTER 9 Quiz Fill in the blanksCopy each of the following statements into you notebook. Fill in the blanks with a word or phrase that correctly completes the sentence. • Most fluid systems contain these components: a to move the fluid; to carry the fluid; to keep the fluid moving in the desired direction; and a pressure to monitor the system’s pressure. • Your makes use of valves to control the flow of blood. Valves can be found in your heart and in your . • Machines like backhoes use large syringe-like pistons called to generate tremendous force. These machines are examples of systems. conductors; pump; veins; valves; rams; body; gauge; hydraulic

23. CHAPTER 9 Quiz Short answerWrite a short answer to each of these questions. • Explain pressure using the particle theory of matter. • Referring to the particle theory of matter, why is it dangerous to heat an aerosol can? • Describe Pascal’s Law in your own words.

24. CHAPTER 9 Quiz Answers Multiple choiceFor each question, select the best answer from the four alternatives. • A system that uses compressed air (or another gas) to do work is called a… • Hydraulic system. • Low pressure system. • Pneumatic system. • Open system. • What happens when a fluid is under pressure? • It contracts. • It expands. • It cools. • Pressure decreases. • If a gas exerts 8 N of force over a 2 m2 area, what is the pressure on that area in N/m2? • 10. • 6. • 4. • 16.

25. CHAPTER 9 Quiz Answers True/FalseIndicate whether each of the statements is TRUE or FALSE. If you think the statement is false, rewrite it to make it true. • FALSE; Liquids are less compressible than gases. • TRUE; Compressing a fluid will decrease its volume. • TRUE; Cooling a fluid will decrease its volume. • TRUE; Valves control the movement of fluid through a tube or pipe.

26. CHAPTER 9 Quiz Answers Fill in the blanksCopy each of the following statements into you notebook. Fill in the blanks with a word or phrase that correctly completes the sentence. • Most fluid systems contain these components: a pump to move the fluid; conductors to carry the fluid; valves to keep the fluid moving in the desired direction; and a pressure gauge to monitor the system’s pressure. • Your body makes use of valves to control the flow of blood. Valves can be found in your heart and in your veins. • Machines like backhoes use large syringe-like pistons called rams to generate tremendous force. These machines are examples of hydraulic systems. conductors; pump; veins; valves; rams; body; gauge; hydraulic

27. CHAPTER 9 Quiz Answers Short answerWrite a short answer to each of these questions. • Explain pressure using the particle theory of matter.Answers may vary.All matter is made up of particles. When fluid particles collide with the inside walls of the container, they transmit a force. This force (per unit area) is pressure. • Referring to the particle theory of matter, why is it dangerous to heat an aerosol can?Answers may vary.As you heat an aerosol can, the particles that make up the substance inside move faster and collide with the inside walls more forcefully. This increase in pressure can become great enough to make the can explode. • Describe Pascal’s Law in your own words. Answers may vary.A force applied to a fluid is distributed equally through all parts of the fluid.

28. test your device and record observations about which parts work efficiently and which do not • make or identify modifications that could improve the effectiveness and efficiency of the system and its components • use your brochure to explain the principles behind how your toy works (or should work) Assessment You will be assessed on how well you • state the design problem or challenge • identify several possible solutions • develop a plan for solving the problem based on one of your possible solutions • complete the plane you develop UNIT C Unit TaskPlaying with Fluids In this Unit Task, you are to use the properties of fluids to design a toy that can move on land, through the air, or on or through water. Toys that move in a controlled manner are preferred. You will also develop a brochure that uses scientific and technology to explain how your toy works. Your brochure will also explain why your toy can be considered “environmentally friendly”.