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1. Push the plunger of cylinder A in so that it goes in 2 cm. Make a note of your observation of the distance output in cylinder C.
2. Push the plunger of cylinder C in so that it goes in 2 cm. Make a note of your observation of the distance output in syringe A.
3. What do you think will happen if the hydraulic system is replaced by a pneumatic system?
4. Replace the water with cooking oil and make a note of the difference / similarity in the functioning of the system.
5. Explain the advantages of using oil rather than water.
6. Summary of the results observed.
ACTIVITY 5:
To examine the connection between output distance, output force and diameter of the cylinder of hydraulic and pneumatic systems consisting of three cylinders
[LO 1.3, 2.3]
You need the following items to conduct this experiment:
1 x 20 mℓ syringe marked C
2 x 10 mℓ syringes marked A and B
3 x connecting tubes of the same size
1 x T connection
Fill syringe C with 10 mℓ water and fill both syringes A and B with 5 mℓ water.
Connect the syringes as indicated in the sketch.
1. Press the plunger of syringe C in 2 cm and indicate the distance output of syringes A and B.
2. Write down your observation.
Summary of the findings of Activities 1 to 5
| Learning outcomes(LOs) |
| LO 1 |
| TECHNOLOGICAL PROCESSES AND SKILLSThe learner will be able to apply technological processes and skills ethically and responsibly using appropriate information and communication technology. |
| Assessment standards(ASs) |
| We know this when the learner: |
| investigates:1.1 identifies and explains a problem, need or opportunity from a real-life context, and investigates the context, the nature of the need, the environmental situation, and the people concerned; |
| 1.2 analyses existing products relevant to an identified problem, need or opportunity based on:safety;fitness for purpose;cost;manufacturing method; |
| 1.3 develops and performs practical testing procedures to determine or compare the suitability or fitness for purpose of relevant properties of materials, electrical or mechanical systems, structures, processes or finished products; |
| 1.4 uses a variety of available technologies and methods to:locate (e.g. use library referencing system, database searches, indexes);collect (e.g. questionnaires, data collection forms, requests for information, information, searches, literature surveys);compare;sort;verify;evaluate (e.g. cross-checking different sources or resources);store information (e.g. filing systems, indexes); |
| designs:1.5 writes or communicates a short and clear statement or a design brief for the development of a product or system related to a context, problem, need or opportunity that has been identified by self; |
| 1.6 lists product and design specifications and constraints for a solution based on all of the design key words listed below:purpose: function, what product will do;appearance and aesthetics: form, colour, shape, feel; |
| 1.7 generates a range of possible solutions that are significantly different from each other, and that show clear links to the design brief and the specifications and constraints; |
| 1.8 chooses possible solutions based on well-reasoned argument related to the specifications and personal options, develops a chosen idea using graphics; |
| makes:1.9 develops plans for making that include all of the following:resource lists;formal drawings showing dimensions or quantities;manufacturing sequence; |
| 1.10 chooses and uses appropriate tools and materials to make designed products with precision and control by measuring, marking, cutting or separating, shaping or forming, joining or combining, and finishing a range of materials accurately and efficiently; |
| 1.11 uses measuring and checking procedures while making to monitor quality and changes, and adapts designs in response to practical difficulties encountered when making products; |
| 1.12 demonstrates knowledge and understanding of safe working practices and efficient use of safe working practices and efficient use of materials and tools. |
| LO 2 |
| TECHNOLOGICAL KNOWLEDGE AND UNDERSTANDINGThe learner will be able to understand and apply relevant technological knowledge ethically and responsibly. |
| We know this when the learner: |
| systems and control:2.3 demonstrates knowledge and understanding of interacting mechanical systems and sub-systems by practical analysis and represents them using systems diagrams:gear systemsbelt drive or pulley systems with more than one stage;mechanical control mechanisms (e.g. ratchet and pawl, cleats);pneumatic or hydraulic systems that use restrictorsone-way valves;systems where mechanical, electrical, or pneumatic or hydraulic systems are combined. |
Memorandum
ACTIVITY 1
A hydraulic system consists of two cylinders that are connected. Each cylinder contains a piston/plunger with a specific diameter and amount of liquid.
When the plunger is pushed in or drawn out, it causes a change in pressure that is propagated through the liquid. This pressure creates the mechanical force or kinetic advantage.
ACTIVTY 2
1. distance of delivery of piston B is 2 cm
2. the same/similar
3. no, the force/power is transferred with equal advantage (advantage =1)
4. The pressure in cylinder A is transferred to cylinder B.
ACTIVITY 3
1. The pressure is propagated from cylinder A to cylinder B.
2. The liquid/fluid propagates the pressure better than the air and offers greater resistance.
ACTIVITY 4
1. 1 cm
2. 4 cm
3. k will propagate less easily and the distance of delivery will not be exactly 1 and 4 cm respectively because air is compressible.
4.&5. See synopsis
6. SYNOPSIS
With a piston that has a small diameter, the distance of delivery is great.
With a piston that has a greater diameter, the distance of delivery is small.
There will be better propagation of the pressure in the cylinder.
The density is greater and the force/power will therefore be propagated better than in water.
ACTIVITY 5
1. 2 cm at A and B respectively
2. The output of two 10-ml syringes each filled with 5 ml of water will be the same as the output of one 20-ml syringe containing 10 ml of water. The larger 20-ml syringe can control two 10-ml syringes if it contains twice (2 x 10 ml) the amount of water.
SYNOPSIS: ACTIVITY 1 – 5
A small force on a small piston/plunger produces a great force on a large piston/plunger.
A small piston/plunger will move over a large distance and a large piston/plunger over a small distance.
The larger piston/plunger is able to control a number of smaller pistons/plungers if its volume is equal to the sum of the volumes of the smaller pistons/plungers and the amount of water in the larger piston/plunger is equal to the combined volumes of the water in the smaller pistons/plungers.
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