Course:         Science & Technology, Grade 8

Teacher:       De Simone

Due Date:     Friday, April 13, 2018

 

Assignment:  Hydraulic/Pneumatic Mechanism Culminating Project


Objective: 

Design, build, test and present a mechanical device (e.g. elevator (lifting), sliding doors (sideways movement), crane (lifting), etc.) utilizing hydraulics (no electronic devices).  You may use other mechanical objects and materials, such as, pulleys and levers. Students will understand how hydraulics and hydraulic fluids are used in everyday mechanical devices (e.g. dump trucks, bus lifts, “jaws of life”, bridge lifts, elevator, pinball, jack-in-the-box, human cannon, etc.) acting as pumps/valves/pistons in a cylinder.


Prior Knowledge

Pascal’s Law:
Pascal’s Law states that when there is an increase in pressure at any point in a confined fluid, there is an equal increase at every other point in the container.

In the mid 1600’s a French philosopher named Blaise Pascal conducted a series of experiments and found interesting things about pressure in a closed system. His Law basically states that no matter how small or large the diameter of the cylinder or the amount of force exerted, the pressure will be constant throughout the fluid in a closed system. Pressure is a measure of the amount of force exerted over a given surface area.   Pressure = Force / Area  (ie. one newton / one cm squared).  According to Pascal, if the pressure exerted on the piston is equal to 1 Newton / cm squared, this would mean that for every single cm squared, regardless of how big the seal, the force would be constant at 1 Newtons. This has very important implication for the use of hydraulic and pneumatic systems. Have you ever watched a car being hoisted up by a hydraulic lift? In these closed systems, a small master cylinder applies pressure to a system in which the “slave” piston (the piston doing the work) is much larger.

A given force applied over a small area creates a high pressure.


This pressure is constant within the whole of the fluid and is transferred to each square cm of the “slave” cylinder. This proves mechanical advantage. If the surface area of the “slave” cylinder is twice as large as that of the “master” cylinder, the resultant force will be twice as large thus allowing the system to lift a bigger load. The “price you pay” as Nabil put it is the displacement of the “slave” piston in relation to the “master” piston and this must be considered when designing solutions to problems.

Criteria
:

The hydraulic/pneumatic mechanism:


Deliverables:

·        Students groups (2 students per group) will create a machine using either hydraulics or pneumatics, performing one or more of the following operations. 

o   lift a weight of 1 kg

o   move an object 10cm

o   open/shut a door (or slide open/close a door/curtain)

·        Draw a basic hydraulic/pneumatic system

·        Draw a model of your hydraulic/pneumatic system (top, front, side views)

 

 

Materials:

 

You can use any of the following (plus any other pre-approved materials):


Written Component:
Answer the following (include your initial/updated design documents with your write-up):

Describe your project, how it works, and your choices of hydraulic and or pneumatics systems for the various movements chosen and why.  What could you have done differently to change/improve the project?


Hydraulics Device Rubric                Name:_______________

 

 

BELOW

AVERAGE

1

 

AVERAGE

2

ABOVE

AVERAGE

3

 

EXCEPTIONAL

4

Teamwork

 

One member dominates the group. Team is not functional

 

Team members

collaborate, engage in positive, supportive

discussion, or

involve all team

members

Team members

collaborate, engage in positive, supportive discussion, and/or involve all team members

Team members

collaborate, engage in positive, supportive discussion, and

involve all team

members

Idea/Strategy

Design Plan

- Plan does not show measurements clearly or is otherwise inadequately labeled

-  Design solution demonstrates a low level of creativity and ingenuity. No creativity or ingenuity.

- Plan provides

clear measurements

and labeling for

most components

-  Design solution

demonstrates an average level of

creativity and ingenuity.

- Plan is neat with

clear measurements

and labeling for

most components

-  Design solution

demonstrates

an above average level of creativity and ingenuity.

- Plan is neat with

clear measurements

and labeling for

all components

-  Design solution

demonstrates an

exceptional

level of creativity and ingenuity.

Execution/

Craftsmanship

 

Hydraulic device has many stray marks and smudges, tears, wrinkles, creases, and frayed edges. No care and very little attention to detail.

Hydraulic device has some stray

marks and smudges, tears, wrinkles, creases, and frayed edges. Minimal care and some attention to detail.

Hydraulic device has few stray marks and smudges, tears, wrinkles, creases, and frayed edges.  Care and attention to detail.  Some case and attention to detail.

Hydraulic device is free from stray

marks and

smudges, tears, wrinkles, creases, and frayed edges.  Extreme care and attention to detail.

Construction - Materials

Inappropriate

materials were

selected and

contributed to a

product that performed poorly.

 

Appropriate

materials were

selected and there was little or no attempt at creative

modification to make any improvements.

Appropriate

materials were

selected and there was an attempt at

creative modification to make them even

better.

Appropriate

materials were

selected and

creatively modified in ways that made them even better.

Scientific Knowledge

Explanations by

several members of the group do not

illustrate much

understanding of

scientific principles

underlying the

construction and

modifications.

Explanations by

most group

members indicate

relatively accurate

understanding of

scientific principles

underlying the

construction and

modifications.

Explanations by

all group members

indicate a relatively

accurate understanding of

scientific principles

underlying the

construction and

modifications.

Explanations by

all group members

indicate a clear

and accurate

understanding of

scientific principles

underlying the

construction and

modifications.

 

 

Grade:                 /25