Course Profile Physics (SPH4C), Grade 12, College Preparation, Public
Unit 2: Hydraulic and Pneumatic Systems
Time: 20 hours
Activity
2.1 | Activity 2.2 | Activity 2.3 | Activity 2.4
| Activity 2.5 | Activity
2.6
Unit Description
This unit develops
students’ understanding of the scientific principles related to hydraulic and
pneumatic systems. Students research and evaluate the social and economic
consequences of applications related to the motion and control of fluids. They
use scientific equipment safely and effectively in designing and carrying out
investigations of fluid statics and dynamics, and of simple hydraulic and
pneumatic systems The End-of-Unit Task involves the construction and testing of
a prototype of a hydraulic or pneumatic system, and a description of the
scientific principles involved in the operation of the device, as well as its
social and economic significance. The inclusion of this device in the Final
Assessment Task is considered.
Unit
Synopsis Chart
|
K/U =
Knowledge/Understanding I = Inquiry C = Communication MC = Making Connections |
|||
|
Activity/ Time |
Learning Expectations |
Assessment Categories |
Tasks/Focus |
|
2.1 Fluid Concepts and
Historical Development 3 hours |
HPV.01, HPV.03,
HP1.01, HP3.01, HP3.03 |
K/U, MC, C |
Introduce
End-of-Unit Task and connect it to Final Assessment Task. |
|
2.2 2.5 hours |
HPV.01, HPV.02,
HP1.01, HP1.04, HP2.02 |
I, K/U |
Discuss: pressure,
static head, and volume. |
|
2.3 3.5 hours |
HPV.01, HPV.02,
HPV.03, HP1.05, HP1.06, HP1.07, HP2.03, HP2.04, HP2.05 |
K/U, I, |
Discussion/investigation:
Pascal’s principle. |
|
2.4 3 hours |
HPV.01, HPV.02.
HP1.01, HP1.02, HP1.03, HP2.01 |
K/U, I, MC |
Internet/video:
view model of laminar flow. |
|
Activity/ Time |
Learning Expectations |
Assessment Categories |
Tasks/Focus |
|
2.5 3.5 hours |
HPV.01, HPV.02, HPV.03, HP1.08, HP2.06, HP3.02, HP3.03 |
K/U, MC, C, I |
Discussion: work, power, time, and application to fluid systems. |
|
2.6 4.5 hours |
HPV.01, HPV.02,
HPV.03, HP1.06, HP2.06, HP3.02, HP3.03 |
I, K/U, |
Design/construct/evaluate:
hydraulic or pneumatic system. Unit test |
* The teacher may
wish to assign just one of these three research activities per student group.
An oral report to the class would ensure all students receive the information.
Activity
2.1: Fluids: Concepts and Historical
Development
Time: 3 hours
Description
In this activity
students are introduced to the requirements of the End-of-Unit Task and also
how the unit relates to the Final Assessment Task. Students consider the
distinction between hydraulic and pneumatic systems while examining concepts
and units related to fluid systems. The historical development and everyday
applications of fluid systems are researched.
Strand(s) & Learning Expectations
Strand(s): Hydraulic and Pneumatic Systems
Learning
Expectations
HPV.01 - demonstrate
an understanding of the scientific principles related to fluid statics and
dynamics, and to hydraulic and pneumatic systems;
HPV.03 - analyse and
describe the social and economic consequences of the development of
technological applications related to the motion and control of fluids;
HP1.01 - define and
describe the concepts and units related to fluids and to hydraulic and
pneumatic systems;
HP3.01 - describe
the historical development of fluid systems, analyse their design, and
determine why these technologies were developed and improved;
HP3.03 - identify
various applications of hydraulic and pneumatic systems in everyday life, and
evaluate the impact of the use of these systems on the quality of life;
SIS.04 - locate,
select, analyse, and integrate information on topics under study, working
independently and as part of a team, and using appropriate library and
electronic research tools, including Internet sites;
SIS.08 - select and
use appropriate SI units, and apply unit analysis techniques when solving
problems;
SIS.12 - identify
and describe science- and technology-based careers related to the subject area
under study.
Prior Knowledge & Skills
·
Research skills
developed in previous courses
Planning Notes
·
The teacher may
wish to review research skills including Internet use.
·
Prepare displays
of both hydraulic and pneumatic systems.
·
Wherever logical,
the teacher could prepare examples of the applications of hydraulic and
pneumatic systems in the home and workplace.
·
Preliminary ideas
on links with the End-of-Unit Task and the Final Assessment tasks could be
explored.
·
The model in the
End-of-Unit Task could be prepared as a group exercise. In this case the
teacher may wish to establish a group “contract” to provide for individual
accountability. Individual log books may be useful in this regard.
Teaching/Learning Strategies
2.1.1 Student
Activity: Students are introduced to the unit and course culminating
activities. The Final Assessment Task for the course requires that students
construct a working model of an industrial or research facility which
incorporates devices developed in each of the units of the course, and a report
explaining each of the devices used, both as individual devices and as a part
of the whole system. A written examination is also included. The End-of-Unit
Task consists of developing the fluid system to be used in the Final Assessment
Task as well as a report describing the scientific principles involved in the
operation of the device. A written test is included for summative evaluation;
it also indicates areas requiring remediation thus preparing students for the
final examination at the end of the course.
Students participate in a teacher-led
discussion, using single concept references to illustrate the meaning of the
terms density, pressure, atmospheric pressure, and absolute pressure. Simple
equations such as: 
are reviewed and/or
developed.
Teacher Facilitation: The teacher leads students in a brainstorming
session so that they may begin to formulate ideas on the culminating
activities. No decision has to be made at this time, but throughout the unit
the teacher directs the students to refer back and refine their ideas. Prepared
demonstrations of hydraulic and pneumatic systems, e.g., bicycle pumps, simple
hydraulic hoists using syringes are used for reference when discussing terms
and concepts and distinguishing between hydraulic and pneumatic systems.
Examples may include tire pumps, hydraulic lift pumps, aquarium aerators,
simple manometers, Hero’s fountain, Cartesian divers, and Boyle’s law apparatus.
This activity could also serve as a diagnostic determination of prior knowledge
as well as misconceptions, e.g., some students will be unaware that a simple
siphon can be established using a hose already filled with liquid – “sucking”
is not a requirement. A wall display could be set up in two columns –
“misconceptions” illustrated on the left as they arise, and “misconceptions
addressed” on the right as they are explained.
2.1.2 Student
Activity: Students research (through library, local industries, and the
Internet) the historical development of a particular fluid system, and prepare
a report/presentation on the design, and the reasons for the development of
that design. Students survey their community, identify examples of applications
of hydraulic and pneumatic systems, and record them in a chart or poster.
Career opportunities are included in the chart, as well as Canadian examples
where appropriate, e.g., auto parts manufacturers.
Teacher
Facilitation: The teacher
checks with the school board regarding the procedures to follow when students
conduct surveys. Examples of the use of fluid systems include: garage hoists,
pneumatic tools such as air wrenches, hydraulic jacks, car brake systems,
dishwashers, washing machines, and soft drink dispensers. To avoid excessive
use of research activities, each of the two investigations could be performed
by different groups. The research investigations could be assessed (by both
teacher and peers), and a class feedback session held, in order to prepare students
for the individual research activity in the End-of-Unit Task. Students would
benefit from a class discussion of the intended assessment criteria with time
to ask clarification questions, and perhaps develop a rubric under teacher
guidance and requiring the teacher’s final approval.
Assessment & Evaluation of
Student Achievement
A short written quiz
could be used to assess students’ achievement of Knowledge/Understanding
expectations. A rubric applied to the report/presentation/poster could be used
to assess Making Connections and Communication skills.
Accommodations
·
Refer to the
Accommodations section in the Course Overview.
Resources
Glenbrook
South The Physics Classroom
– www.glenbrook.k12.il.us/gbssci/phys/Class/BBoard.html
– www.glenbrook.k12.il.us/gbssci/phys/mmedia/index.html
University
of the Virgin Islands
– www.uvi.edu/SandM/Physics/SCI3xxWeb/Plumbing/FluidStatics.html
– www.uvi.edu/SandM/Physics/SCI3xxWeb/Plumbing/FluidDynamics.html
Website for Rubrics
and Assessment
Assessment of Science and Technology Achievement Project (York University)
– http://edu.yorku.ca/science/ASAP/
Ministry of
Education Curriculum Unit Planner
Refer to the
Resources in the Course Overview
Activity
2.2: Static Pressure Head
Time: 2.5 hours
Description
Students investigate
the pressure exerted at different depths in a fluid and consider the height of
a fluid column that is held up by static pressure. Factors affecting the static
pressure head are investigated, and analysed quantitatively, both in liquids
and gases. The use of a static pressure head as a device for marking level
heights is investigated. Practical applications are considered.
Strand(s) & Learning Expectations
Strand(s):
Hydraulic
and Pneumatic Systems
Learning
Expectations
HPV.01 - demonstrate
an understanding of the scientific principles related to fluid statics and
dynamics, and to hydraulic and pneumatic systems;
HPV.02 - design and
carry out investigations of fluid statics and dynamics, and of simple hydraulic
and pneumatic systems;
HP1.01 - define and describe
the concepts and units related to fluids and to hydraulic and pneumatic;
HP1.04 - identify
factors affecting static pressure head, analyse static pressure head in
quantitative terms, and explain its effects in liquids and gases;
HP2.02 - identify factors
that affect the static pressure head in fluids by carrying out procedures,
compare theoretical and empirical values, and account for discrepancies;
SIS.01 - demonstrate
an understanding of appropriate safety practices by selecting, operating, and storing
electrical equipment, components, and materials in accordance with the Ontario
Electrical Code, and by acting in accordance with Workplace Hazardous Materials
Information System (WHMIS) legislation in selecting and applying appropriate
techniques for handling, storing, and disposing of laboratory materials;
SIS.02 - select
appropriate instruments and testing equipment and use them effectively and
accurately in collecting observations and data;
SIS.03 - demonstrate
the skills required to design and carry out experiments related to the topics
under study, controlling major variables and adapting or extending procedures
where required;
SIS.06 - use
appropriate scientific models (theories, laws, explanatory devices) to explain
and predict the behaviour of natural phenomena;
SIS.07 - analyse and
synthesize information for the purpose of identifying problems for inquiry, and
solve the problems using a variety of problem-solving skills;
SIS.08 - select and
use appropriate SI units, and apply unit analysis techniques when solving
problems;
SIS.09 - select and
use appropriate numeric, symbolic, graphical, and linguistic modes of to
communicate scientific ideas, plans, and experimental results;
SIS.10 - communicate
the procedures and results of investigations and research for specific purposes
using data tables, laboratory reports, and research papers, and account for
discrepancies between theoretical and experimental values;
SIS.11 - express the
result of any calculation involving experimental data to the appropriate number
of decimal places or significant figures;
SIS.12 - identify
and describe science- and technology-based careers related to the subject area
under study.
Prior
Knowledge & Skills
·
Laboratory and
problem-solving skills developed in previous courses e.g., GRASP (Given;
Required; Analysis; Solution; Paraphrase) method for problem solving
·
Density and
pressure concepts from Grade 10 Weather unit
Planning
Notes
·
Prepare class
investigations of pressure at a depth and pressure head (Caution: do not
let students use apparatus containing mercury).
·
Prepare extra
equipment in anticipation of student designed investigations.
·
Prepare problem
sets.
·
The teacher may
wish to have a list of career connections available.
·
Identify links
with the End-of-Unit Task and the Final Assessment Task.
·
Safety goggles
should be used in activities using fluids under pressure.
Teacher/Learning
Strategies
2.2.1 Student
Activity: With teacher direction, students derive the pressure differential
at two different depths in a fluid (for constant density), 
and its application
to the pressure at points below the surface of a body of water 
. They discuss the dependence of the pressure on vertical
depth alone and view a demonstration using equilibrium tubes in which liquids
stand at the same level in tubes of different shapes. They also discuss
applications such as large volume dams versus small volume dams containing
water to the same depth. Students then solve problems relating to pressure at a
depth.
Teacher Facilitation: The teacher provides a full derivation of 
that will help
students grasp many pressure concepts. A discussion of the misconception that
small dams need not be as structurally strong as larger dams will help
understanding of the reliance on vertical depth (and density) alone.
2.2.2 Student
Activity: Students discuss the use of the expression 
to represent the
“static pressure head” (pressure available through gravitational potential
energy). The pressure head can also act as a pressure gauge, e.g., mercury
barometer, open-tube manometer. Students consider “shallow well” versus
“submersible” pumps.
Teacher Facilitation: The term “static pressure head” is widely used
in industry in different ways; avoid student confusion by using the
gravitational energy analogy. The teacher may use Boyle’s law apparatus to show
pressure differentials. “Grip testers,” using a column of liquid to measure a
student’s grip strength, are available at some suppliers. Ask the students why
a “shallow well” pump is unable to raise water more than 10 m. A discussion of
the evolution of pressure units, e.g., mm Hg, may help enrich students’
understanding.
2.2.3 Student
Activity: Students compare the calculation of the static pressure head of
an incompressible liquid (constant density) with that of a column of gas. They
then discuss the density of the Earth’s atmosphere and the relevance to air
pressure. They solve problem sets involving static pressure head in different
liquids and gases, and absolute pressure at various positions in the Earth’s
atmosphere.
Teacher Facilitation: The teacher leads a problem-solving session to
facilitate students’ demonstration of appropriate SIS expectations. Include a range
of levels of difficulty, as well as an extension into “unknown” areas, such as
the absolute pressure at 300 m above the surface of Jupiter.
2.2.4 Student
Activity: Students working in groups design a hydraulic level, and use the
device to set marks of equal height (for each group) throughout the classroom.
The groups then develop a list of possible real-world uses for such a level.
Teacher Facilitation: The hydraulic level has been used throughout
the ages and in many cultures. The device consists of a reservoir with a long
clear latex tube (approximately 0.5 cm in diameter) emerging from its base. The
apparatus is filled with coloured water. The device is set with the reservoir
liquid level at a desired level in one location; the free end of the tubing is
then moved and marks are set at the same level in other locations as necessary.
This device can be used in a variety of locations, both indoors and out, for a
variety of purposes, e.g., construction of decks, fences, walls, docks, ponds,
installation of chair rails and decorative borders. The teacher facilitates the
identification of several of these purposes.
Assessment & Evaluation of
Student Achievement
The Inquiry skills
demonstrated by the students during the “hydraulic level” investigations could be
assessed by requiring a scientific lab report to be submitted, and using a
rubric. Knowledge/Understanding expectations could be assessed through a
written test or through their solutions to problem sets.
Accommodations
·
Students could be
further challenged by problems set in locations with different atmospheric
pressures such as on other planets, or in cities at different elevations.
·
Assign
measurement heights so that all students are safely included in the “hydraulic
level” activity.
Resources
University
of the Virgin Islands
www.uvi.edu/SandM/Physics/SCI3xxWeb/Plumbing/FluidStatics.html
www.uvi.edu/SandM/Physics/SCI3xxWeb/Plumbing/FluidDynamics.html Video
Water Level:
www.pbs.org/cgi-registry/2wgbh/thisoldhouse/big_img.pl?search_style=img&is_id=9001618)
Home
improvement videos.
“Do It Yourself”
contracting books.
Activity
2.3: Pascal’s Principle and Fluid
Systems
Time: 3.5 hours
Description
Students investigate
Pascal’s Principle and its application to the transmission of force through a
fluid. The components used in hydraulic and pneumatic systems, including their
symbols are studied. The relationship among force, area, pressure, volume, and
time are investigated and relevant problem sets are completed. Applications in
everyday life, including related careers, are considered.
Strand(s) & Learning Expectations
Strand(s): Hydraulic and Pneumatic Systems
Learning
Expectations
HPV.01 - demonstrate
an understanding of the scientific principles related to fluid statics and
dynamics, and to hydraulic and pneumatic systems;
HPV.02 - design and
carry out investigations of fluid statics and dynamics, and of simple hydraulic
and pneumatic systems;
HPV.03 - analyse and
describe the social and economic consequences of the development of
technological applications related to the motion and control of fluids;
HP1.05 - state
Pascal’s principle and explain its applications in the transmission of forces
in fluid systems;
HP1.06 - describe
common components used in hydraulic and pneumatic systems;
HP1.07 - apply
quantitatively the relationships among force, area, pressure, volume, and time
in hydraulic and pneumatic systems;
HP2.03 - verify
Pascal’s principle through experimentation;
HP2.04 - draw simple
hydraulic or pneumatic circuits, using correct circuit symbols;
HP2.05 - determine,
through experimentation, the relationships among force, area, pressure, volume,
and time in a hydraulic and pneumatic system;
SIS.01 - demonstrate
an understanding of appropriate safety practices by selecting, operating, and
storing electrical equipment, components, and materials in accordance with the
Ontario Electrical Code, and by acting in accordance with Workplace Hazardous
Materials Information System (WHMIS) legislation in selecting and applying
appropriate techniques for handling, storing, and disposing of laboratory
materials;
SIS.02 - select
appropriate instruments and testing equipment and use them effectively and
accurately in collecting observations and data;
SIS.03 - demonstrate
the skills required to design and carry out experiments related to the topics
under study, controlling major variables and adapting or extending procedures
where required;
SIS.04 - locate,
select, analyse, and integrate information on topics under study, working
independently and as part of a team, and using appropriate library and
electronic research tools, including Internet sites;
SIS.07 - analyse and synthesize information for the purpose of
identifying problems for inquiry, and solve the problems using a variety of
problem-solving skills;
SIS.08 - select and
use appropriate SI units, and apply unit analysis techniques when solving
problems.
Prior Knowledge & Skills
·
Laboratory and
problem-solving skills developed in previous courses
·
Research and
bibliographic skills developed in previous courses
Planning Notes
·
Prepare class
investigations of Pascal’s Principle.
·
Prepare extra
equipment in anticipation of student-designed investigations, especially of
hydraulic and pneumatic systems.
·
Prepare problem
sets involving Pascal’s principle.
·
The teacher may
wish to have a list of career connections available.
·
Identify links
with the End-of-Unit Task and the Final Assessment Tasks.
·
Teachers may wish
students to prepare a log book detailing applications of hydraulic and
pneumatic systems in daily life, and recording thoughts on social and economic
consequences.
Teaching/Learning Strategies
2.3.1 Student
Activity: Students participate in a teacher-led discussion on Pascal’s
principle and its application in the transmission of forces in a fluid system.
Students then perform a laboratory investigation to verify Pascal’s principle.
Teacher Facilitation: The teacher may wish to have models
demonstrating Pascal’s principle on display in the classroom during the
discussion. Pascal’s principle laboratory apparatus is available from most
supply companies. The teacher encourages students to design their own
verification experiments and reviews the experimental design process as
appropriate.
2.3.2 Student
Activity: Students investigate (through the Internet, library/resource
centre, and local companies) simple hydraulic and pneumatic systems in common
use, including the common components used, e.g., cylinders, valves, motors,
fluids, hoses, connectors, pumps, reservoirs. Students draw the systems using
the corresponding circuit symbols and produce a written and/or graphic report
of their findings.
Teacher Facilitation: The teacher suggests common hydraulic or
pneumatic systems, e.g., pop drink dispensers at movie theatres, air brakes,
waste disposal trucks, many pieces of heavy transportation/construction
equipment, tool and die facilities, and milking machines on dairy farms. The
teacher may wish to organize a visit by (or to) a local mechanic who could
explain brake, steering, and hoist systems for example. Teachers may wish to focus
the activities within this and following lessons on fluid systems most evident
in their community.
2.3.3 Student
Activity: Given the challenge to investigate the relationship among force,
area, pressure, volume, and time, students design a hydraulic or pneumatic
system and carry out related experimentation.
Teacher Facilitation: The teacher begins with a demonstration of a
simple two-cylinder system (plastic syringes), applying a known force through a
small area to lift an object, and verify the relationship 
. Students are then
encouraged to make additions and refinements to the basic system (changing
volume; changing time of application of effort force; let output piston become
input piston to another system). An important component of the design process
is the evaluation of the design. The teacher may encourage students to self-
and/or peer assess their designs and make modifications as necessary. Students
are reminded to reflect on the End-of-Unit Task and how this assignment might
relate to it.
(Note: The plastic syringes suggested are an inexpensive way to
demonstrate Pascal’s Principle. One can also use the master and slave cylinders
from the braking system of a car available from a school’s auto shop or any
wrecker.)
2.3.4 Student
Activity: Students solve qualitative and quantitative problems related to
hydraulic and pneumatic systems. Students continue research on applications of
fluid systems to everyday life and identify and analyse social and economic
consequences of the use of hydraulic and pneumatic systems, e.g., robotics.
They update log-book notes if used (see Planning Notes).
Teacher Facilitation: The teacher prepares qualitative and
quantitative questions, and wherever reasonable, relates the question to use in
industry or the home. The teacher invites and encourages students to offer and
support their opinions on social and economic significance.
Assessment & Evaluation of
Student Achievement
By means of a
written quiz, or the solutions to the problem sets, the students demonstrate
achievement of Knowledge/Understanding. A checklist applied to the
investigations will assess Inquiry skills. The report and/or log book on
applications of hydraulic or pneumatic systems can be used to assess
achievement in both Making Connection, and Communication expectations.
Accommodations
·
As an extension,
fluid systems operated through electronic circuits may be investigated (this
will link to the next unit).
·
A personal
glossary of terms used in lessons, activities, and problem sets can be
established by students as needed (see Appendix A – Building Effective
Glossaries, Grade 12 Science, Workplace Course Profile).
Activity
2.4: Laminar Flow: Bernoulli’s
Principle
Time: 3 hours
Description
Students identify, through class discussion and
experimentation, the factors involved in laminar and turbulent flow.
Bernoulli’s principle is investigated and its applications, over a wide range
of circumstances, are examined. Students solve qualitative problems, based on
Bernoulli’s principle. Possible connections of laminar flow and Bernoulli’s
principle to the End-of-Unit Task are considered.
Strand(s) & Learning Expectations
Strand(s): Hydraulic and Pneumatic Systems
Learning
Expectations
HPV.01 - demonstrate
an understanding of the scientific principles related to fluid statics and
dynamics, and to hydraulic and pneumatic systems;
HPV.02 - design and
carry out investigations of fluid statics and dynamics, and of simple hydraulic
and pneumatic systems;
HP1.01 - define and
describe the concepts and units related to fluids and to hydraulic and
pneumatic systems;
HP1.02 - identify
factors affecting laminar flow, and describe examples of laminar flow;
HP1.03 - state
Bernoulli’s principle and explain some of its applications in the fields of
technology and health;
HP2.01 - demonstrate
Bernoulli’s principle through experiments;
SIS.01 - demonstrate an understanding of
appropriate safety practices by selecting, operating, and storing electrical
equipment, components, and materials in accordance with the Ontario Electrical
Code, and by acting in accordance with Workplace Hazardous Materials
Information System (WHMIS) legislation in selecting and applying appropriate
techniques for handling, storing, and disposing of laboratory materials;
SIS.02 - select appropriate
instruments and testing equipment and use them effectively and accurately in
collecting observations and data;
SIS.03 - demonstrate
the skills required to design and carry out experiments related to the topics
under study, controlling major variables and adapting or extending procedures
where required;
SIS.06 - use
appropriate scientific models (theories, laws, explanatory devices) to explain
and predict the behaviour of natural phenomena;
SIS.07 - analyse and
synthesize information for the purpose of identifying problems for inquiry, and
solve the problems using a variety of problem-solving skills;
SIS.08 - select and
use appropriate SI units, and apply unit analysis techniques when solving
problems;
SIS.09 - select and
use appropriate numeric, symbolic, graphical, and linguistic modes to
communicate scientific ideas, plans, and experimental results;
SIS.10 - communicate
the procedures and results of investigations and research for specific purposes
using data tables, laboratory reports, and research papers, and account for
discrepancies between theoretical and experimental values;
SIS.12 - identify
and describe science- and technology-based careers related to the subject area
under study.
Prior Knowledge & Skills
·
Laboratory and
problem-solving skills developed in previous courses
Planning Notes
·
Prepare a
“carousel” of interactive laboratory activities through which students pursue
an understanding of the concepts of Bernoulli’s principle.
·
Prepare extra
equipment for student-designed investigations.
·
Prepare problem
sets.
·
The teacher may
wish to have a list of career connections available.
·
Identify links
with the End-of-Unit Task and the Final Assessment Tasks.
Teacher/Learning Strategies
2.4.1 Student
Activity: Students discuss the criteria for laminar and turbulent flow in
terms of the motion of the particles in the medium. Models for the two types of
flow are observed, either as a poster display or through the Internet (see
Resources). The factors affecting laminar and turbulent flow are summarized.
Teacher Facilitation: The teacher encourages students to explain the
behaviour of the two types of flow in terms of the particle model for matter.
Arrange for video clips (or Java Applets on the Internet) of the phenomena if
possible (see Resources).
2.4.2 Student
Activity: With teacher direction, students derive the equation for rate of
flow
Rate of flow = velocity × cross section: R=vA and the Equation of
Continuity: 
. Students solve problem sets based on these two equations.
Teacher Facilitation: The teacher encourages students to see the
logic behind each equation rather than just another “magic formula” to add to
the list. Visual aids (graphics, videos) are helpful since many students will
be meeting these concepts for the first time. Prepare problem sets for student
practice. The teacher may wish to extend the derivation of the equation of
continuity to include the diameter of a pipe, d: 
.
2.4.3 Student
Activity: Students complete a carousel of activities designed to
demonstrate Bernoulli’s principle. In addition to the stations set up by the
teacher, students use a “vacant” station to design and test their own activity
to demonstrate Bernoulli’s principle. Students then develop with the teacher the
actual wording of Bernoulli’s Principle. Misconceptions, e.g., those related to
aircraft wings, helicopter rotors, and the spinning a golf ball to affect
range, are addressed.
Teacher Facilitation: The teacher sets up examples that demonstrate
the basic concept, e.g., ping pong ball held up in an air flow; blowing between
strips of paper; blowing between plastic pop bottles sitting on rollers; ping
pong ball in inverted funnel; cotton spool and cardboard disk; and venturi tube
demonstrator. Encourage students to try safe variations of each activity. When
students have completed all activities, the teacher discusses with them a
statement of Bernoulli’s Principle relating lateral pressure to velocity of
fluid. Misconceptions relating to Bernoulli’s principle are discussed, e.g., a
common misconception is that a wing on an airplane is held up by direct force
of the air against the lower surface, rather than the pressure differences. Note:
See June 2001 OAPT newsletter.
2.4.4 Student
Activity: Through class discussion and research, students identify a
variety of applications of Bernoulli’s principle. Individual students (or small
groups) then prepare a poster display for each application.
Teacher Facilitation: The teacher ensures that a sufficient number
of applications are identified to allow each group to prepare a poster on a
different item. Examples of applications include: spray atomizers, propellers,
spoilers on racing cars, turbine blades in jet engines, sails, tarpaulins on
truck loads, aneurisms in blood vessels, plumbing vents (“stink pipes”),
airplane wings, ski jumping, baseball pitching (the “curve ball”), chimney
flow, carburetors, “egg-beater” wind turbines. The teacher may wish to include
an investigation of a “venturi tube” and the equation 
.
Assessment & Evaluation of
Student Achievement
A written quiz could
be used to assess Knowledge/Understanding (both problem-solving skills and
concepts) of fluid flow and Bernoulli’s principle. A checklist applied to the
poster could be used to assess Making Connection skills. A checklist for
observing students during laboratory activities would assess Inquiry skills.
Accommodations
·
The teacher may
wish to challenge students with an examination of Bernoulli’s Equation and
Torricelli’s Theorem and related problems (see Appendix 2-1), although
Bernoulli’s Equation is beyond the scope of this course.
·
Another challenge
could involve the use of the Pitot Tube to measure the local velocity within a
laminar flow (see Resources).
Resources
NASA: Glen
Resource Centre
– http://wright.grc.nasa.gov – This provides a Java Applet for laminar flow as
well as other Bernoulli principle applications.
SimScience
Sites
– http://simscience.org/fluid/red/golf top.html
History of
Aviation site:
– http://www.aviation-history.com/theory/lam-flow.htm
Innovative
technology Solutions Corporation:
– http://www.itsc.com/movies
(downloadable video clips on fluid dynamics)
Sri
Vankateswara College of Engineering:
– http://www.svce.ac.in?~msubbu/FM-WebBook/Unit-III/PitotTube.htm
How Stuff
Works Site
– www.howstuffworks.com
From the
Ground UP. Ottawa, Canada:
Aviation Publishers Co. Limited, 1996. ISBN 09690054-9-0
p. 20
(Bernoulli), p. 57 (carburetor)
OAPT June 2001
newsletter
Activity
2.5: Work, Power, and Robotics
Time: 3.5 hours
Description
Students investigate
the relationships among work, power, and time in hydraulic and pneumatic
systems and solve relevant problems. Research is conducted, and a report
prepared, on the application of hydraulic and pneumatic systems to the use of
robotics, including an analysis of social and economic consequences, and a
career component. Students research and design the components required for the
End-of-Unit Task.
Strand(s) & Learning Expectations
Strand(s): Hydraulic and Pneumatic Systems
Learning
Expectations
HPV.01 - demonstrate
an understanding of the scientific principles related to fluid statics and
dynamics, and to hydraulic and pneumatic systems;
HPV.02 - design and
carry out investigations of fluid statics and dynamics, and of simple hydraulic
and pneumatic systems;
HPV.03 - analyse and
describe the social and economic consequences of the development of
technological applications related to the motion and control of fluids;
HP1.08 - analyse, in
quantitative terms, the relationships among work, power, and time in hydraulic
and pneumatic circuits;
HP2.06 - design,
construct, and evaluate a hydraulic or pneumatic system and solve problems as
they arise;
HP3.02 - identify
and analyse some of the social and economic consequences of the use of robotic
systems for many different kinds of operations;
HP3.03 - identify
various applications of hydraulic and pneumatic systems in everyday life, and
evaluate the impact of the use of these systems on the quality of life;
SIS.04 - locate, select,
analyse, and integrate information on topics under study, working independently
and as part of a team, and using appropriate library and electronic research
tools, including Internet sites;
SIS.07 - analyse and
synthesize information for the purpose of identifying problems for inquiry, and
solve the problems using a variety of problem-solving skills;
SIS.08 - select and
use appropriate SI units, and apply unit analysis techniques when solving
problems;
SIS.09 - select and
use appropriate numeric, symbolic, graphical, and linguistic modes of
representation to communicate scientific ideas, plans, and experimental
results;
SIS.12 - identify
and describe science- and technology-based careers related to the subject area
under study.
Prior Knowledge & Skills
·
Research skills
developed in previous courses and earlier in this course
·
Problem-solving
skills developed in previous courses and earlier in this course
·
Power concepts
from Grade 9 Electricity unit
Planning Notes
·
The teacher may
wish to review research skills, including Internet use and etiquette.
·
Local industries
could be contacted to identify local examples of robotic use.
·
College calendars
could be reviewed for robotics courses offered.
·
Prepare group
contracts (see Assessment and Evaluation of Student Achievement) if using these
to build in individual accountability for group work.
·
Computer software
packages can be very useful for making virtual systems and robots.
Teaching/Learning Strategies
2.5.1 Student
Activity: Students participate in a teacher-led discussion on the
application of work, power, and time to fluid systems. Students solve relevant
problem sets.
Teacher Facilitation: The teacher may wish to apply the concepts of
work, power, and time to fluid systems, and discuss the concept of distance
moved, e.g., a load force far greater than the effort force may be exerted, but
the distance moved by the load will be correspondingly less; foot pedal versus
brake calliper movement. Virtual systems can be designed using a variety of
software packages.
2.5.2 Student
Activity: Students research robotics, their design and use, e.g., to handle
hazardous materials, in space such as the Canadarm, manoeuvring heavy objects
as an example of fluid system application. Students analyse the social and
economic consequences of robotics and describe how robotic use has affected the
career training of people employed in industries now reliant on robotics, e.g.,
college robotics courses.
Teacher Facilitation: Remind students to treat robotics as an
example of fluid systems. Encourage students to investigate robotics courses
offered at colleges and universities. The teacher may wish to consult with a
colleague from the technical education faculty. Be prepared for some students’
requests to construct a robot for the End-of-Unit Task.
2.5.3 Student
Activity: Students research and design the components they will need for
the End-of-Unit Task, based on the concepts they have learned in the unit. With
the guidance of the teacher, the students establish small working groups, assign
roles (research, model construction, testing) and prepare a plan of action. The
scaling factor (to allow this device to be included in the final project) is
discussed and determined.
Teacher Facilitation: Remind students that they must plan a device
for which they will be able to provide historical perspective and scientific
explanations, as well as applications to everyday life. If students ask to
build a robotic component remind them that it must be based on fluid system
principles, although the teacher may wish to allow electronic controls as a
link to the electronics unit.
Assessment & Evaluation of
Student Achievement
Student problem
solutions provide evidence of achievement of Knowledge/Understanding
expectations and can be recorded using a marking scheme or checklist. Research
and design activities may be used to assess Inquiry skills, while reports on
robotics and their applications provide evidence of achievement of Making
Connection and Communication expectations. A rubric may be used. To accommodate
individual contributions to a group activity have students keep a logbook. The
teacher may decide to “contract” the group work ahead of time so that
individual accountability is built into the group process.
Accommodations
·
Encourage
interested students to investigate aeronautic, computer, and/or heavy machinery
applications of robotics.
Resources
NASA
Robotics
–
http://spacelink.nasa.gov/Instructional.Materials/CurriculumSupport/Technology/Robotics
Link to
robotic supplies – www.ee.ualberta.ca
How Stuff
Works site – www.howstuffworks.com
The
Incredible Machine – from
Sierra
Interactive
Physics – from Knowledge
Revolution
Activity
2.6: End-of-Unit Task (Construction of
a Prototype and Unit Test)
Time: 4.5 hours
Description
This End-of-Unit
Task allows the students to draw on the knowledge and skills they have acquired
throughout the unit to design, construct and evaluate a hydraulic or pneumatic
system or device. They describe the scientific principles involved in the
operation of the system, as well as its social and economic significance.
Strand(s) & Learning Expectations
Strand(s): Hydraulic and Pneumatic Systems
Learning
Expectations
HPV.01 - demonstrate
an understanding of the scientific principles related to fluid statics and
dynamics, and to hydraulic and pneumatic systems;
HPV.02 - design and
carry out investigations of fluid statics and dynamics, and of simple hydraulic
and pneumatic systems;
HPV.03 - analyse and
describe the social and economic consequences of the development of
technological applications related to the motion and control of fluids;
HP1.06 - describe
common components used in hydraulic and pneumatic systems;
HP2.06 - design,
construct, and evaluate a hydraulic or pneumatic system and solve problems as
they arise;
HP3.02 - identify
and analyse some of the social and economic consequences of the use of robotic
systems for many different kinds of operations;
HP3.03 - identify
various applications of hydraulic and pneumatic systems in everyday life, and
evaluate the impact of the use of these systems on the quality of life;
SIS.01 - demonstrate
an understanding of appropriate safety practices by selecting, operating, and
storing electrical equipment, components, and materials in accordance with the
Ontario Electrical Code, and by acting in accordance with Workplace Hazardous
Materials Information System (WHMIS) legislation in selecting and applying
appropriate techniques for handling, storing, and disposing of laboratory
materials;
SIS.02 - select
appropriate instruments and testing equipment and use them effectively and
accurately in collecting observations and data;
SIS.03 - demonstrate
the skills required to design and carry out experiments related to the topics
under study, controlling major variables and adapting or extending procedures
where required;
SIS.04 - locate,
select, analyse, and integrate information on topics under study, working
independently and as part of a team, and using appropriate library and
electronic research tools, including Internet sites;
SIS.05 - compile,
organize, and interpret data, using appropriate formats and treatments,
including tables, flow charts, graphs, and diagrams;
SIS.07 - analyse and
synthesize information for the purpose of identifying problems for inquiry, and
solve the problems using a variety of problem-solving skills;
SIS.09 - select and
use appropriate numeric, symbolic, graphical, and linguistic modes of to
communicate scientific ideas, plans, and experimental results;
SIS.10 - communicate
the procedures and results of investigations and research for specific purposes
using data tables, laboratory reports, and research papers, and account for
discrepancies between theoretical and experimental values;
SIS.12 - identify
and describe science- and technology-based careers related to the subject area
under study.
Prior Knowledge & Skills
·
Inquiry skills
required to plan and carry out an investigation
Planning Notes
·
Collect and have
available the equipment that the students have indicated they will need.
·
Check each
student proposal for appropriateness, e.g., safety and scaled size.
·
Decide on, and
prepare, the assessment instruments you wish to use for this activity.
Teaching/Learning Strategies
2.6.1 Student
Activity: Students design and construct a model hydraulic or pneumatic
system, and prepare a circuit diagram using correct symbols showing the
components used. Students also prepare a report describing the scientific
principles behind the operation of the system, an evaluation of its
performance, as well as an account of its social and economic significance.
Teacher Facilitation: If small groups are employed, the teacher
encourages all members to participate and requires that logbook entries be kept
to clearly record individual contributions. Review the “group contract” if
previously employed (see Activity 2.5). Examples of systems could include:
braking system on a car, hydraulic cranes, hydraulic presses, water pump
systems, robotics, “Canadarm” type systems, air brakes, shock absorbers, forced
air systems, and pneumatic tools.
2.6.2 Student Activity: Students complete
the unit test.
Teacher Facilitation: The teacher designs a test which may include a
practical component for evaluation of skills acquisition.
Assessment & Evaluation of
Student Achievement
A rubric could be
used to assess the planning, design, and construction of the system.
Knowledge/Understanding expectations could be assessed through oral questioning
and the written reports. The display of the model itself, along with individual
logbook entries, will offer evidence of achievement of Communication
expectations. A checklist applied to the written report could assess
achievement of Making Connections expectations. A marking scheme is used for
the test along with a checklist for the practical component.
Accommodations
·
Encourage students
to extend the model or consider combining models into larger systems.
·
Allow the use of
student-created study sheets when completing the written portion of the test.
Resources
NASA
Robotics
– http://spacelink.nasa.gov/Instructional.Materials/CurriculumSupport/Technology/Robotics
Link to
robotic supplies – www.ee.ualberta.ca
How Stuff
Works site – www.howstuffworks.com
Appendix 2-1
1. Bernoulli’s
Equation
In a steady flow of
a fluid of density 
, the pressure P, the fluid speed v, and the
height h above a reference level at any two points are related by the
equation:
2. Torricelli’s
Theorem
The velocity of the
fluid emerging through an orifice at the bottom of an open tank is
. The rate at which the fluid flows from the orifice is 
Appendix 2-2
Unit Problem Set
Knowledge/Understanding/Problems
1. How is a pneumatic system different from a
hydraulic system?
2. How are force and pressure different?
3. A cylindrical tank for gasoline is 2.8 m long
and 1.4 m in diameter. What is the mass of the gasoline that the tank will
hold? (density of gasoline = 680.0 kg/m3)
4. If the tank in the previous question is
standing on its circular end, what is the pressure it will exert on the surface
upon which it stands?
5. A 90.0 kg person walks across a floor wearing
golf cleats. If we assume that at one instant 10 cleats are in contact with the
floor, and that each cleat has an area of 0.0625 mm2 what is the pressure
(in kPa) that the person exerts on the floor?
6. The atmospheric pressure at sea level is
approximately 1.0 x 105Pa. What is the force at sea level that the
atmosphere exerts on the top of a table 218 cm long by 82.0 cm wide?
7. During an approaching thunderstorm, the air
pressure outside your house drops suddenly from
1.018 × 105Pa to 0.940 × 105 Pa. Assuming that your house
is very well weather-proofed so that the inside pressure has not had a chance
to equalize, what is the magnitude of the net force exerted on a window that
measures 1.90 m × 2.90 m?
8. The deep end of a swimming pool has a depth
of 3.20 m. What is the pressure at the bottom of the pool if the atmospheric
pressure above it is 1.022 × 105 Pa?
9. If you drink a can of pop (density =1.0 × 103
kg/m3) using a straw, and the gauge pressure inside your mouth when
you suck is 1250 Pa, how high is the pop drawn up into the straw?
10. When drinking pop through a straw is it fair
to say that you “sucked” the liquid up? Explain.
11. How is drinking a liquid from a straw similar
to using a shallow well pump set at ground level to draw water from a depth?
12. The large piston in a hydraulic jack used to
raise cars is 24 mm in diameter and the small one is
6.8 mm.
a) What force must be exerted on
the small piston to lift a 3.0 tonne mass.
b) A lever is often used to
reduce the force needed on the small piston. How long should the effort arm of
an ideal lever be to reduce the applied force to 90.0 N if the load arm is 3.8
cm?
13. How does laminar flow differ from turbulent
flow?
14. In your own words explain Bernoulli’s
Principle.
15. Why does the tarpaulin covering a truck cargo,
bulge outwards when the truck is travelling down the highway?
16. During hurricane force winds the roof of a
house may be “blown outwards.” Why is this so?
17. Water flows at 3.8 m/s through a rubber hose
of diameter 1.8 cm.
a) If the water emerges at 22 m/s
what is the nozzle diameter?
b) Calculate the rate of flow of
the water.
18. Water is pouring from a circular aperture of
cross-sectional area 1.2 cm2, in the side of a cylindrical water
tank. At what rate is the water lost from the tank if the aperture is 3.8 m
below the level of the water in the tank? (Torricelli’s theorem)
19. Water flows at 8.0 m/s through a pipe of
diameter 3.2 cm. If this pipe is now connected to a smaller pipe of diameter
1.6 cm:
a) What is the velocity in the
smaller pipe?
b) Will the rate of flow be
different in the smaller pipe?
Appendix
2-2 (Continued)
Inquiry/Making
Connections
20. Water flows through a horizontal pipe at a
speed of 3.0 m/s under an absolute pressure of 240 k Pa. If the pipe narrows to
a diameter of one-half the original, what is the new absolute pressure?
21. Use your resource centre to determine
atmospheric conditions on the surface of the planet Jupiter and predict how
results using the grip tester mentioned in Activity 2 would compare on Jupiter
with those on Earth?
22. Visit (or contact) your local automotive
centre and obtain exact specifications for two hydraulic systems, such as the
garage hoist and an automobile hydraulic brake system.
23. Hold two pages vertically so that they are
about 4 cm apart. Blow between them and describe the behaviour of the two
pages. Explain the result.
24. Explain how a submersible pump can pump water
up from a depth of 70 m or more while a pump operating from the surface cannot
draw water from more than about 10 m.
25. A water tower situated in a town holds water
at a height of 20.0 m. If the tower holds 6.0 × 105 kg of water when
full, and is vented to the atmosphere at the top, calculate the gauge pressure
that the water has at a faucet in a house at ground level.
26. A hospital patient is receiving an intravenous
feed of nutrient solution. The nutrient sac hangs from a support stand at a
height of 65.0 cm. above the point of infusion, and is vented to the
atmosphere. At this height a nutrient solution of density 1050 kg/m3
can barely enter the vein. What is the gauge pressure of the patient’s venous
blood?
27. A dentist’s chair weighs 1580 N and rests on a
piston with a cross-sectional area of 1200.0 cm2. What force must
the dentist exert on the smaller piston (cross-sectional area 68.0 cm2)
in order to raise the chair?
28. In the hydraulic system used in disc brakes a
force applied to the brake pedal causes it to rotate as part of a lever system
and in turn apply a force perpendicularly to the input piston in the master
cylinder. The pressure is then transmitted through the brake fluid to the outer
plungers on either side of the disc. These plungers are connected at their ends
to the brake linings. If a force of 10.0 N is applied to the brake pedal and
the mechanical advantage of the pedal lever system is 3.00, calculate the force
applied to each side of the disc.
Radius of master cylinder input cylinder = 9.60 mm
Radius of outer plungers = 1.94 cm
Communication
29. Explain to a friend how Bernoulli’s principle
applies to wind-surfing.
30. Prepare a poster in which you use Bernoulli’s
principle to explain how a “curve ball” is pitched in baseball.
31. An aneurysm is an abnormal enlargement of a
blood vessel. Prepare an explanation to be used with the class why this results
in an increased pressure being exerted on the walls of the blood vessel.
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