TECHNICAL SCIENCES

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TECHNICAL SCIENCES

GUIDELINES FOR PRACTICAL ASSESSMENT TASKS

GRADE 12

2019

These guideline documents consist of 22 pages.

Technical Sciences 2 DBE/PAT 2019 NSC


TABLE OF CONTENTS

ITEM PAGE NUMBER

1. INTRODUCTION

3

2. TEACHER GUIDELINES

4

3. LEARNER GUIDELINES

4

4. EVIDENCE OF MODERATION

5

5. DECLARATION OF AUTHENTICITY

6

6. EXPERIMENT INSTRUCTIONS AND WORKSHEETS FOR EXPERIMENT 1

7


12


15

EXPERIMENT 1: TO VERIFY THE PRINCIPLE OF CONSERVATION OF LINEAR

MOMENTUM EXPERIMENT 2: TO DETERMINE THE CHARACTERISTICS OF A P-N JUNCTION

DIODE EXPERIMENT 3: TO ELECTROPLATE AN IRON NAIL WITH COPPER



1. INTRODUCTION The 17 Curriculum and Assessment Policy Statement subjects which contain a practical component all include a practical assessment task (PAT). These subjects are: • AGRICULTURE: Agricultural Management Practices, Agricultural Technology • ARTS: Dance Studies, Design, Dramatic Arts, Music, Visual Arts • SCIENCES: Computer Applications Technology, Information Technology,

Technical Sciences • SERVICES: Consumer Studies, Hospitality Studies, Tourism

• TECHNOLOGY: Civil Technology, Electrical Technology, Mechanical Technology, Engineering Graphics and Design and Technical Sciences

A practical assessment task (PAT) mark is a compulsory component of the final promotion mark for all candidates offering subjects that have a practical component and counts 25% (100 marks) of the examination mark at the end of the year. The practical assessment task for Technical Sciences Grade 12 consists of three experiments. The experiments are COMPULSORY for ALL candidates offering Technical Sciences in Grade 12. The PAT is implemented during the first three terms of the school year. The PAT allows learners to be assessed regularly during the school year and it also allows for the assessment of skills that cannot be assessed in a written format, such as tests or examinations. It is therefore important that schools ensure that all learners complete the practical assessment tasks within the stipulated period to ensure that learners are promoted at the end of the school year. The planning and execution of the PAT differs from subject to subject. The experiments should be administered under supervised conditions. Moderation of the experiments may take place on site and can include learners redoing the experiments in the presence of the moderator.



2. TEACHER GUIDELINES

2.1 How to administer the PATs

• The following documents must be available for all formal experiments: o Experiment instructions explaining the procedures to be followed for the experiments o The worksheets which include questions to be answered under examination conditions o The teacher's guidelines with experiment instructions, worksheets and marking

guidelines (the teacher's guidelines MUST NOT be released to the learners) o Teachers should compile marking guidelines (memoranda) for the real results of

the experiments conducted (teachers should do the experiments themselves FIRST)

• The teacher should hand out ONLY the Instruction Sheet for the conduct of the experiment.

• Experiments must be performed individually or in pairs. However, if sufficient apparatus is not available, experiments can be performed in groups. Each learner must record his/her OWN INDIVIDUAL data and observations.

• Each learner must have his/her OWN worksheet and answer the questions INDIVIDUALLY under exam conditions.

• Only once all the learners have performed the experiments and they are all seated and ready to answer questions may teachers hand out a worksheet to each learner. Examination conditions have to be applied.

• If it is not possible to perform the experiment and answer the worksheet on the same day, the teacher must collect the learners' data after a part of the experiment has been done. This data must be kept at school. Only when learners finalise the experiment may the data be returned to them.

2.2 Moderation of the PATs

For moderation the following are required either in a separate class or in a laboratory: • List of names of learners who are sampled for district moderation • Equipment/Apparatus/Chemicals placed ready at workstations • Instruction sheets and worksheets (empty) for sampled learners to answer questions

For moderation the following documents are required in the teacher's file: • Index stating all tasks with raw and weighted marks • All instruction sheets for all experiments • Marking guidelines for all experiments, with ticks and totals • Composite working mark sheet for all learners showing raw and weighted marks • Evidence of internal moderation

For moderation the following documents are required in the learners file: • Index stating all tasks with raw and weighted marks • Answer sheets for all experiments • Declaration of authenticity

3. LEARNER GUIDELINES

3.1 This practical assessment task for Grade 12 consists of THREE experiments.

3.2 Compilation of the PAT should start in term 1, monitored through terms 2 and 3 and completed in term 3.

3.3 The PAT counts 25% of your final promotion mark for Grade 12.

3.4 All work in the PAT must be your own. Group work will NOT be allowed.

3.5 Show ALL calculations clearly and include units. Round off your answers to TWO decimal places. Use correct SI units.



3. EVIDENCE OF MODERATION LEARNER'S NAME:

-------------------------------------------------------------------------------------------------

SCHOOL

-------------------------------------------------------------------------------------------------

MODERATION:

SCHOOL-BASED

SIGNATURE OF TEACHER

DATE SIGNATURE OF HOD

DATE

--------------------- ------------------ ---------------------- ----------------------

PRACTICAL COMPONENT

MAXIMUM MARK

LEARNER'S MARK

(TEACHER)

MODERATED MARK

(SCHOOL)

MODERATED MARK

(DISTRICT)

MODERATED MARK

(PROVINCE) EXPERIMENT 1 40

EXPERIMENT 2 30

EXPERIMENT 3 30

TOTAL 100

SCHOOL STAMP



4. DECLARATION OF AUTHENTICITY NAME OF THE SCHOOL: ……………………………………………………….. NAME OF LEARNER: …………………………………………..………………... (FULL NAME(S) AND SURNAME) CLASS: ……….……………………………………………………………………. NAME OF TEACHER: …………………………………………………………….

SCHOOL STAMP

I hereby declare that the tasks submitted for assessment is my own original work and has not been previously submitted for assessment or moderation. ___________________________________ ____________ SIGNATURE OF CANDIDATE DATE As far as I know, the above declaration by the candidate is true and I accept that the work offered is his or her own. ___________________________________ ____________ SIGNATURE OF TEACHER DATE



5. EXPERIMENT INSTRUCTIONS AND WORK SHEETS EXPERIMENT 1: OPTION 1 1. TITLE: PRINCIPLE OF CONSERVATION OF LINEAR MOMENTUM 2. AIM: To verify the principle of conservation of linear momentum. 3. APPARATUS/EQUIPMENT: • Runway/track • Two trolleys with compressible spring and plunger/buffer rod • Stop watch/timer • Mass balance • Ruler/Metre stick/Measuring tape 4. PROCEDURE Arrange the apparatus as illustrated in the diagram below.

• Clean the runway and trolley wheels to remove any dirt. • Ensure that the mass balance (digital/manual) is at zero before measuring the mass of the

trolleys. • Measure and record the mass of each trolley. • Place the two trolleys on the runway. • Release one of the buffer rods by tapping the release rod. The trolleys should move apart. • Ensure that the trolleys hit the barriers simultaneously. • In case the trolleys do not hit the barriers simultaneously change the initial position until they

hit the barriers at the same time. • Mark the initial position and measure the distance between the initial position and the barriers

for each trolley. • Repeat this procedure THREE times. • Record the:

o Distance between the initial position and the barriers for each trolley o Time taken to hit the barriers



WORKSHEET FOR CONSERVATION OF LINEAR MOMENTUM: OPTION 1

40

1. PRACTICAL SKILLS MARKS Precaution. • Cleaning the runway and the wheels of the trolleys. • Ensure that the mass balance (digital/manual) is at zero before measuring the

mass of the trolleys.

2

Set up: • Locating a suitable starting position for the two trolleys so that they hit the

barriers simultaneously. • Marking the initial position.

2

Measuring skills: • Measuring the masses of the trolleys. • Measuring the distance between the starting position and barrier for each

trolley accurately. • Use of the timer or stop-watch (start, stop) accurately.

6

TOTAL [10]

2. Name TWO controlled variables for this experiment. (2)

3. Name TWO possible experimental errors. (2)

4. Suggest how the errors mentioned QUESTION 3 can be prevented. (4)

5. Data representation and interpretation of results

TRIAL MASS (kg) TIME (s) DISTANCE (m) (between initial position and barrier)

1 Trolley A Trolley B



Average Trolley A (1) (1) Trolley B (1) (1)

6. What is the initial velocity of the system? (2)

7. Calculate the:

7.1 Velocity (vf) of trolley A after the explosion (4)

7.2 Velocity (vf) of trolley B after the explosion (2)

8. Calculate the total momentum:

8.1 Before the explosion (4)

8.2 After the explosion (3)

9. Based on the results obtained above, is momentum conserved? (1)

10. Give a reason for the answer to QUESTION 9. (2) [40]



EXPERIMENT 1: OPTION 2 1. TITLE: PRINCIPLE OF CONSERVATION OF LINEAR MOMENTUM 2. AIM To verify the principle of conservation of linear momentum using a trolley, a wooden

block/object and a ticker timer. 3. APPARATUS/EQUIPMENT: • Runway • Trolley • Mass piece/wooden block/object (with a mass less than that of the trolley). • Power Supply • Ticker Timer • Ticker Tape • Mass Balance • Ruler/Metre stick/Measuring tape

4. PROCEDURE: • Clean the runway and trolley wheels to remove any dirt. • Ensure that the mass balance (digital/manual) is at zero before measuring the mass of the

trolley and object. • Measure and record the mass of the trolley and the object. • Place the trolley on the runway. • Elevate one end of the runway slightly such that the trolley is stationary, but moves at a

constant speed when given a slight push. • Drop the mass piece/object on the trolley after it has moved half the runway. • When the object/mass is dropped on the trolley, ensure that both move together as a unit

after collision. • Attach/secure the ticker tape to the trolley. • Ensure that the ticker tape moves freely through the timer and is long enough to cover the

length of the entire runway. • Switch on the ticker timer and give the trolley a gentle push. • Switch off the timer and remove the tape once the trolley-object system has reached the end

of the runway. • Mark the start and end points on the tape. • Analyse the ticker tape:

o Ignore the unclear initial dots on the tape. o Mark 20 space intervals on the tape before and after the collision. o Use a ruler to measure the length of the 20 space intervals.

• Repeat this procedure THREE times.



• Record the results in the table below.

TRIAL MASS

(kg) TIME

(s) DISTANCE (m)

(length of 20 space intervals) 1 Trolley

Trolley + object 2 Trolley


Trolley + object



WORKSHEET FOR CONSERVATION OF LINEAR MOMENTUM: OPTION 2 40

1. PRACTICAL SKILLS MARKS Precautions.

• Cleaning the runway and the wheels of the trolleys. • Ensuring that trolley-object system move together after the collision.

2

Measurement of the masses of the trolley and object. 2 Set up:

• Elevation of the runway at a correct inclination. • Placing trolley on the runway (initially stationary, move at constant velocity

when given a slight push). • Dropping the mass piece/object on the trolley midway on the runway. • Ensuring that the ticker tape is attached to the trolley that it runs smoothly.

4

Analysis of the ticker tape: • Mark 20 space intervals on the tape before and after the collision. • Measuring the length of the 20 space intervals.

2

Total [10]

1. Name TWO controlled variables for this experiment. (2)

2. Name ONE possible experimental error. (1)

4. Give a reason for elevating the runway. (2)

5. Data representation and interpretation of results TRIAL MASS (kg) TIME (s) DISTANCE (m)

(length of 20 space intervals) 1 Trolley



Trolley + object Average Trolley (1) (1)

Trolley + object (1) (1)

6. Use the frequency of the ticker timer to calculate its period (T). (3)

7. Calculate the:

7.1 Time taken for the 20 space interval. (3)

7.2 Velocity (vi) of the trolley before the collision. (3)

7.3 Velocity (vf) of the trolley and mass piece system after the collision (2)

8. Calculate the total momentum:

8.1 Before the collision. (4)

8.2 After the collision. (3)

9. Based on the results obtained, is momentum conserved? (1)

10. Give a reason for the answer to QUESTION 9. (2) [40]



6. EXPERIMENT INSTRUCTIONS AND WORK SHEETS EXPERIMENT 2 1. TITLE: THE CHARACTERISTIC A FORWARD BIASED P-N JUNCTION DIODE 2. AIM: To determine the characteristic of a P-N diode. NOTE: Choose METHOD A or METHOD B. METHOD A 3. APPARATUS/EQUIPMENT: • Two multi-meters • Variable DC supply • 1N4002 diode • Connecting wires • 150 kΩ potentiometer • 3,3 Ω, 1 W carbon resistor/any type of resistor • Breadboard/circuit board • Mini toggle switch (SPST)

4. PROCEDURE • Ensure that the power source is switched OFF and then set it to 1,2 V before commencing

with any connections. • Connect the diode, the potentiometer, the 3,3 Ω resistor and the switch in series with the

ammeter and the power source as shown in the diagram above. • Connect the positive terminal of the power source to the P-region and the negative terminal to

the N-region of the diode. • Connect the voltmeter in parallel with the diode. • Set the ammeter scale to 50 mA and the voltmeter to 1 V scale. • Ensure that the circuit is correctly connected. • Close the switch and switch on the power supply. • Vary the supply voltages and complete the table provided. • Record the corresponding current and voltage readings of the diode. • Reverse the connection of the diode in the circuit and observe the ammeter and voltmeter

readings.

OR



METHOD B 3 APPARATUS/EQUIPMENT: • Two multi-meters • Variable DC supply • 1N4007 diode • Connecting wires • 1 kΩ resistor • Breadboard/circuit board • Mini toggle switch (SPST)

4 PROCEDURE • Ensure that the power source is switched OFF and then set it to 0 V before commencing with

any connections. • Connect the diode, the 1 kΩ resistor, the switch, the ammeter and the power source in series

as shown in the diagram above. • Connect the positive terminal of the power source to the P-region and the negative terminal to

the N-region of the diode. • Connect the voltmeter in parallel with the diode. • Set the ammeter scale to 50 mA and the voltmeter to 1 V scale. • Ensure that the circuit is correctly connected. • Close the switch and switch on the power supply. • Vary the supply voltages and complete the table provided • Record the corresponding current and voltage readings of the diode. • Reverse the connection of the diode in the circuit and observe the ammeter and voltmeter

readings. TABLE

V Supply (V) V Diode (V) I Diode (mA)



WORKSHEET FOR DETERMINING THE CHARACTERISTIC OF A P-N DIODE

30

1. PRACTICAL SKILLS MARKS Precaution: • Power source initially switched off.

2

Set up: • Correctly connected components in the circuit:

o Diode, ammeter, switch, resistors and power source in series. o Voltmeter in parallel with the diode.

• Voltmeter and ammeter (multimeters) set to correct scale. • Positive terminal of the power source connected to the P-region and the

negative terminal to the N-region of the diode. • Being able to vary the supply voltage.

10

TOTAL [12] 2. Give a reason for: 2.1 Initially switching off the power source (2) 2.2 Using a high resistor in the circuit (2) 3 Complete the table below based on the results.

V Supply (V) V Diode (V) I Diode (mA)

(3) 4. Draw a graph of the current (y-axis) vs. potential difference (x-axis) of the diode. (6) 5. When is a diode forward-biased? (2) 6. What will be the ammeter reading if the connection of the diode is reversed? (1) 7 Interpret the results of this experiment. (2) [30]



7. EXPERIMENT INSTRUCTIONS AND WORK SHEETS

EXPERIMENT 3

1. TITLE: ELECTROLYTIC CELL

2. AIM: To electroplate an iron nail with copper

3. APPARATUS CHEMICALS • Power source • Copper plate/rod • Glass beaker • Retort stand with clamp • Connecting wires with crocodile clips • Steel wool/sand paper/steel wire brush • Non galvanised iron nail/any metal object • Stirrer • Chemical balance/digital balance.

• Copper sulphate/Copper nitrate • Water

[Source: https://www.brighthubengineering.com/structural-engineering

4. PROCEDURE: • Prepare a 1 mol.dm-3 aqueous solution of copper sulphate in a beaker. • Stir the mixture until all the crystals have dissolved. • Clean the iron nail. • Attach the crocodile clip which is connected to the positive terminal of the power source to the

copper plate. • Attach the crocodile clip which is connected to the negative terminal of the power source to

the iron nail. • Place the copper plate and iron nail in the solution. • Ensure that the electrodes are secured and do not fall. • Ensure that the electrodes do not touch each other when conducting the experiment. • Switch on the power source and leave it for 30 minutes. • Switch off the power source and remove the nail and copper plate from the solution. • Allow both electrodes to dry.

https://www.brighthubengineering.com/structural-engineering



EXPERIMENT 3 WORKSHEET FOR ELECTROLYTIC CELL

30 1. PRACTICAL SKILLS

MARKS Wearing of appropriate safety clothing, e.g. laboratory coat, goggles, gloves. 1 Correct and safe handling of glassware (no breakage), chemicals (no spillage/ swallowing).

2

Correct use of apparatus: o Accurate measurement of the mass of the copper salt o Correct volume of water measured

2

Ensuring that electrodes were cleaned with steel wool (wire brush/sand paper) before conducting the experiment.

1

Correct assembling and handling of apparatus. 2 Experimental procedure followed in a logic sequence. 2

TOTAL 10 2. State ONE safety precaution that should be adhered to. (1) 3. Why should the electrodes: 3.1 Be cleaned prior to the experiment (2) 3.2 Not touch each other during the experiment (2) 4. Explain the observation at the iron nail electrode in terms of oxidation and reduction. (2) 5. Name TWO experimental factors that might have an influence on the electroplating

process. (2) 6. Which electrode is the: 6.1 Anode (1) 6.2 Cathode (1) 7. Write down the: 7.1 Half reaction taking place at the anode. (2) 7.2 Half reaction taking place at the cathode. (2) 7.3 Net ionic equation of the cell. (2) 8. Is the reaction spontaneous or non-spontaneous? (1) 9 What energy conversion takes place in this cell? (2) [30]


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TECHNICAL SCIENCES GRADE 12 PAT WORKING MARK SHEET 2019

TERM 1 TERM 2 TERM 3

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No. SURNAME NAME 40 40 30 30 30 30 100 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 23 24 25 26 27 28 29 30 Average

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