Improving exam technique in the sciences

1 – Success with calculations.

Improving exam technique

When students are active in improving exam technique they achieve increased examination scores. In turn, these improvements can be the difference between securing a place at a prestigious University or falling frustratingly short.

Exam technique can be underdeveloped in whole-class teaching because it needs repeated practise to develop fully and be optimized.
One-to-one tuition offers unparalleled opportunities to focus on and practice perfect performance.

Calculations

Calculations play a crucial role in how a science candidate is assessed in examinations.
To ensure that students perform calculations correctly and score 100% of the marks on offer, they are encouraged to show their working out.

So what does ‘showing your working’ look like?

I have found that students using the following acronym effectively are invariably successful in significantly improving exam techniques.

NAUTE FRICUSS (pronounced naw-tee frick-us)

NAUTE:

This acronym means ‘Never Approximate Until The End.’

When students perform a multi-stage set of calculations, it is tempting to truncate or approximate the numerical answer at each stage. It is much better to keep the precision of the number in the calculator.

Each time approximation occurs the resulting value can move further from the true value.

It is crucial to express the final value to the appropriate number of significant figures. Therefore, approximation should only occur after the final calculation.

FRICCUSS:

This acronym has the following meaning:

F: Formula – write down the formula that you are using

R: Rearrange – rearrange the formula to make the variable that you are calculating become the subject of the formula

I: Insert – insert the data values into the formula

C: Calculate – carry out the calculation

C: Check – repeat the calculation using your calculator. Look carefully at the final value and evaluate whether it is reasonable

U: Units – consider what the units should be and state them

S: Standard form – express the value in standard form (where applicable)

S: Significant figures – state the value to a reasonable number of significant figures

WHY DO PEOPLE LOVE AND HATE SCIENCE?

Example 1: GCSE Chemistry style

In a chromatography experiment, colour B is found to have an Rf value of 0.84.

Colour B is found to move 3.1 cm.

Calculate the distance moved by the solvent. [2 marks]

FRICCUSS in action:

F: Formula – write down the formula that you are using

Rf = (Distance moved by colour B) / (Distance moved by the solvent)

R: Rearrange – rearrange the formula to make the variable that you are calculating become the subject of the formula.

Distance moved by solvent = (Distance moved by colour B) / (Rf)

I: Insert – insert the data values into the formula.

Distance moved by solvent = (3.1) / (0.84) [M1]

C: Calculate – carry out the calculation.

Distance moved by solvent = (3.1) / (0.84) = 3.6904762

C: Check – repeat the calculation using your calculator. Look carefully at the final value and evaluate whether it is reasonable.

Distance moved by solvent = (3.1) / (0.84) = 3.6904762

This seems to be a sensible distance for the solvent to have travelled.

U: Units – consider what the units should be and state them.

Distance moved by solvent = (3.1) / (0.84) = 3.6904762 cm

S: Standard form – express the value in standard form (where applicable)

Not applicable in this case since the data given is not in standard form.

S: Significant figures – state the value to a reasonable number of significant figures.

The distance of 3.6904762 cm is beyond the precision used by the experimenter so it is appropriate to express as 3.7 cm. [M2]

SCIENTIFIC LANGUAGE AND TERMINOLOGY

Example 2: GCSE Physics style

Calculate the work done by a cyclist when her power output is 220 W for 1500 seconds. [3 marks]

FRICCUSS in action:

F: Formula

Power = (Work done) / (Time) [M1]

R: Rearrange

Work done = Power x Time [M2]

I: Insert

Work done = 220 x 1500

C: Calculate

Work done = 220 x 1500 = 330000

C: Check

Work done = 220 x 1500 = 330000

This seems to be a sensible amount of work done.

U: Units

Work done = 220 x 1500 = 330000 J

S: Standard form

Not applicable in this case since the data given is not in standard form.

S: Significant figures

330000 J is expressed to appropriate precision in keeping with the data
used.  [M3]

EXAM ANXIETY: HOW TO KEEP CALM DURING EXAMS

Example 2a: AS Chemistry style

Calculate the mass, in kg, of a single 58Ni+ ion.

Assume that the mass of a 58Ni+ ion is the same as that of a 58Ni atom. (The Avogadro constant L = 6.022 x 1023 mol-1) [1 mark]

FRICCUSS in action:

F: Formula

L = (Molar mass in kg) / Mass of 1 ion in kg)

R: Rearrange

Mass of 1 ion in kg = Molar mass in kg / L

I: Insert

Mass of 1 ion in kg = (58.0/1000) / (6.022 x 1023)

C: Calculate

Mass of 1 ion in kg = (58.0/1000) / (6.022 x 1023) = 9.631357 x 10-26

C: Check

Mass of 1 ion in kg = (58.0/1000) / (6.022 x 1023) = 9.631357 x 10-26

This seems to be a sensible mass for one ion in kg.

U: Units

9.631357 x 10-26 kg

S: Standard form

The value calculated is expressed in standard form.

S: Significant figures

The mass needs to be expressed to appropriate precision, in keeping with the data used, therefore 3 significant figures are used since 58.0 is to 3 significant figures, hence 9.63 x 10-26 kg. [M1]

… and that’s quite a lot of work for 1 mark… but if you want 100% you need to embrace every challenge.

LEARNING SCIENCE – IS THERE A SCIENCE TO IT?

Example 2b: AS Chemistry style

In a time-of-flight mass spectrometer the kinetic energy (KE) of a 58Ni+ ion was 1.389 x 10-13 J.

Calculate the velocity of the ion using the equation:

KE = 0.5mv2

(m = mass/kg and v = velocity/ms-1)         [2 marks]

FRICCUSS in action:

F: Formula

KE = 0.5mv2

R: Rearrange

v2 = 2KE/m

I: Insert

v2 = (2 x 1.389 x 10-13) / 9.63 x 10-26 [M1]

C: Calculate

v2 = (2 x 1.389 x 10-13) / 9.63 x 10-26 = 2.8847352 x 1012

v = √2.8847352 x 1012 = 1.6984508 x 106

C: Check

v = √2.8847352 x 1012 = 1.6984508 x 106

This seems to be a sensible velocity for an ion in a Time-of-flight mass spectrometer.

U: Units

1.6984508 x 106 ms-1

S: Standard form

The value calculated is expressed in standard form.

S: Significant figures

The mass needs to be expressed to appropriate precision in keeping with the data used. Therefore 3 significant figures, 1.70 x 106 ms-1 [M2]

… again lots of work, this time for 2 marks … but thanks to your improving exam technique and NAUTE FRICCUSS the marks are secured

A bit about the author, John S.

John is a fully qualified teacher with over 30 years of classroom experience teaching science. He has been a successful Head of Science and Head of Chemistry in a number of schools. As well as preparing learners for exam success, John has extensive experience training teachers, marking exams, and writing content for exam boards and publishers.

In addition to teaching science at KS3 and GCSE, and Chemistry at A-Level, he is very interested in the science of learning, and effective online teaching. John is passionate and enthusiastic about enabling learners to grow in confidence, motivation and to be the best they can be.

John is a very helpful, caring, reliable and flexible tutor, providing a bespoke service that supports learner progress in knowledge, understanding, the development of study skills and exam technique. In delivering these he always puts the learner front and centre.

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