Practical Skills Assessments

Here you do practical tasks set by your teacher who observes how you tackle the tasks, and gives you a mark out of 9.

Unit 6

Following instructions and
group work

Selecting and using
equipment

Organisation and safety
 

4A
Plans and works with some
guidance, selecting appropriate techniques and following instructions.

4B
Selects and uses suitable
equipment, including at least two
complex instruments or
techniques appropriate to the
A2 course

4C
Demonstrates safe working
practices in using a range of
equipment appropriate to the
A2 course

5A
Plans and works without
guidance, selecting appropriate techniques and following instructions.  Participates in group work.

5B
Selects and uses suitable
equipment, including more than two complex instruments and techniques  appropriate to the A2 course.

5C
Demonstrates safe working practices in some of the more complex procedures encountered on the A2 course

6A
Plans and works without
guidance, selecting appropriate techniques and following complex
instructions.  Participates in group work.

6B
Selects and uses suitable
equipment with due regard to
precision, including a wide range of at least 6 complex instruments and techniques appropriate to the A2 course.

6C
Consistently demonstrates safe working practices in the more complex procedures encountered on the A2 course.

Total 3 marks

Total 3 marks

Total 3 marks

PSA experiments are done throughout the year during routine practical work, and your best marks will be submitted to the Board.  In reality, most Physics A2 students should get all 9 marks.

 

Follow instructions and work with others

If you can follow instructions for a standard procedure, and work in a group, making a contribution, you will get at least 2 marks.  If you can do a more complex procedure, you will get 3 marks. 

A standard procedure might be to set up a circuit to measure voltage and current in a circuit.  A complex procedure would require a number of steps to set up the apparatus.  An example of this may be to measure the energy supplied by a heater and measurement of temperature of water, possibly with a data-logger.

Working with others means just that.  In many a job advert you will see the phrase, “…must be a good team player…”, which is management-speak for working in co-operation with others.  In a commercial aeroplane, the pilot flies the aircraft.  The co-pilot does not sit there for the ride.  He (or she) assists the pilot in the many checklists for the flight, tunes the communication and navigation radios, keeps track of the flight-plan, and generally reduces the work-load of the pilot.

It does not mean:

These men doing diddly-squat would say that they are working with others in this study in indolence.  They are achieving nothing.

It means that each student takes responsibility for getting part of the experiment set up and data recorded.  You need to work co-operatively so that the task gets done quickly, and effectively.  While it’s most comfortable to do it with friends, you may find yourself having to work with someone you might not necessarily get on with socially.  Tough.  In life, you will have to work with people who might not be your “cup of tea”, or whom you positively cannot stand.

Groups that get right idea about working together get the work done quickly and effectively.

Question 1

Think about how well you work together with others.  How much time do you spend as a group discussing anything other than the task in hand?  Is there anything you can do to improve this?

Answer

Selecting and Using Equipment

This skill area concerns the choice and use of equipment for a procedure.  At AS level, you use standard laboratory equipment such as a digital multimeter and select the appropriate range.

In this picture, the 600 volt AC range has been chosen.  You can see that there are a lot of other ranges that can be chosen.  Other standard equipment includes:

Not very high-tech, but perfectly good for harvesting accurate data.

To gain all 3 marks, you need to do repeat readings where appropriate.  It is good practice to do this anyway.

Complex instruments include micrometer screw gauges, and spectroscopes, requiring some interpretation of observations to convert them into meaningful results.

Question 2

You have a 15 volt DC power supply.  What range would you use to measure this voltage?

Answer

A more challenging instrument to use is an analogue meter.  A school analogue meter consists of a basic meter, to which you add components that are appropriate to the measurements.  These are:

And there is another factor you need to consider.  What is the value of the quantity you are going to measure?  If you are going to measure 20 mA, you will get nowhere if you use a 10 amp shunt.  And then which scale you use.  If you use the 10 V multiplier, you would use the "10 range", so that a reading of 4.6 gives a reading of 4.6 V.  If you have a 20 V multiplier, then a reading on of 4.6 on the 10 range would give 9.2 volts.

Question 3

You are using the 2 amp shunt.  The needle shows 7.2 on the "10 range".  What is the current?

Answer

Organisation and Safety

Organisation

Parkinson’s Law, coined by Cyril Northcote Parkinson (1909 – 1993), tells us that:

Work expands so as to fill the time available for its completion.

In other words a lot of time can be wasted.  And this happens frequently in practical work.  One person (if that) does the work, while others watch.  The comments about working with others are relevant here as well.  The picture above (the study in indolence) is a result of poor organisation.

To avoid wasting time, and get the maximum benefit from practical work, you need to:

If one member of the group is not sure how to do the experiment, show them.  If they are not sure of the physics, help them; peer teaching is very effective.

On completion of the practical work, each student should make its own copy of the results.  Then get on with doing the graph and answering the question.  Remember that the more you get done in class, the less you have to do for homework.

 

Safety

No activity in college or work is so important that people should put themselves or others at risk.  The risks in a school physics laboratory are very low, but students still have a responsibility to look after their own safety and that of others.

Risks in physics experiments include:

 

Safety should always be considered before carrying out any experiment.  If equipment is faulty, it must be reported to the teacher.  It should go without saying that no action should be taken to compromise safety by abusing equipment or doing unauthorised experiments.

You should get into the habit of making your own risk assessment, even though your teacher will have carried out a risk assessment previously.  In this, you should consider:

As always this is not an exhaustive list.

Question 4

 Write a risk assessment for carrying out an experiment to investigate resistivity.

Answer

And when you have done the risk assessment, follow it.  You may want to use goggles.  You might decide on using a heat-proof mat, and so on.

Any shout of “ouch!” means that you are not working safely.