SEC G3 EMS Density Evidence and Museum Caption

A museum label must be correct before anyone reads it

A school museum plans to exhibit an irregular metal object beside a measuring cylinder, a graph and a short description. The poster has an attractive headline: ‘Our test proves this is pure iron.’ Its table says that the object has a mass of 78.4 g and displaces 9.8 cm³ of water. Its graph shows a straight line with a gradient near 8.0 g/cm³. Yet its draft caption also says that the density is 9.2 g/cm³, the exhibit is 97% accurate, and the test proves the object is made of a particular metal. The danger is not one terrible mistake. It is a chain of small, believable claims that do not fit together.

This learner’s guide teaches an evidence-release decision. You will verify the measurement, reconcile the mathematics, correct the English and decide exactly what may be printed. It is an EMS exercise because physics supplies the measurement, mathematics supplies the model and English supplies the meaning visitors take away. The case is fictional. None of the data represents a real artefact, an examination prediction or a laboratory certificate. The larger skill is real: a conclusion is only as dependable as the weakest step that supports it.

Quick answer: the seven decisions before publication

First, identify what was measured directly. Second, check that each unit names the quantity it belongs to. Third, calculate volume from the final and initial water levels. Fourth, calculate density from the mass and displaced volume without including the balance’s container or tare mass. Fifth, compare the calculation with the graph, including its axes and intercept. Sixth, separate what is observed from what is inferred or merely assumed. Seventh, rewrite the public caption with grammatical accuracy and appropriate limits. If a figure fails one test, put the caption on hold; do not rescue an attractive sentence by inventing precision.

The seven decisions are not separate subjects pasted together. They represent a dependency chain. A graph cannot repair an invalid cylinder reading. A polished description cannot turn density into an identification test. A plausible material name cannot justify the phrase ‘proves pure’. Under examination conditions, the same sequence prevents a learner from skipping a missing premise merely because a numerical answer looks familiar.

Where this volume belongs in the learning route

Volume 1159 explains the physics of water displacement, including the meniscus, bubbles, full immersion and errors that change the apparent volume. Read its irregular-solid experiment if that foundation is weak. Volume 1160 explains why a mass–volume line may have a gradient that represents density while a nonzero intercept can come from a container or balance offset. Revisit the mass–volume graph guide for coordinate calculations. Volume 1161 teaches the editing of a laboratory notice when agreement, tense or comparison changes what the reader understands.

This chapter deliberately does not replace those owners. It tests whether the student can use all three in a final publication decision. A younger learner can cross from PSLE Science to secondary scientific reasoning through the PSLE-to-G1/G2/G3 Science guide. For broader support, the existing Secondary English hub, Mathematics transition guide and experimental skills guide remain the owners of general learning methods. This volume owns one distinctive task: reconciling a museum density caption when measurements, calculations and words disagree.

Official SEC context, checked for 2027

SEAB’s 2027 G3 school-candidate syllabus directory, updated 26 October 2026, identifies G3 English Language as K300 (previous reference 1184), G3 Mathematics as K310 (previous reference 4052), and G3 Physics as K323 (previous reference 6091). Combined Science (Physics, Chemistry) is K326, while the other two combined-science combinations have distinct codes. SEC begins in 2027 as the common certificate for subject levels G1, G2 and G3; the change in certificate name does not by itself create an entirely new set of disciplinary principles.

The K323 Physics syllabus covers density = mass ÷ volume and identifies determination of an irregular solid’s density as a practical preparation example. The K310 Mathematics syllabus stresses interpretation of tables and graphs, contextual problems, reasoning and communication; Papers 1 and 2 are each 90 marks, 50%, and 2 hours 15 minutes. The K300 English syllabus assesses effective language choices across writing, comprehension, listening and oral communication. This composite rehearsal is original study practice, not a separate official SEC ‘EMS paper’ or a claim that the examination will use a museum display.

Make a claim ledger before doing a calculation

Draw three mental columns: claim, evidence needed, and verdict. The claim ‘the sample’s recorded mass is 78.4 g’ needs a suitable balance reading and an assurance that the sample, not its container, was measured. The claim ‘its displaced volume is 9.8 cm³’ needs two valid cylinder readings under consistent conditions. The claim ‘density is 8.0 g/cm³’ needs both of those quantities divided correctly. The claim ‘the sample is pure iron’ requires evidence of identity and composition that the stated density test alone cannot provide. The claim ‘97% accurate’ requires a defined reference or assessment of accuracy, which is absent.

The ledger reveals a common category mistake. A number written beside a laboratory instrument is an observation only if it is actually read from the instrument. A number obtained by subtraction or division is calculated. A statement about the material’s identity is an inference requiring further supporting methods. The ability to label each kind of sentence is useful in Science structured responses and in English passages that ask what a writer can fairly conclude. The ledger also exposes missing information before an essay-length explanation wastes time.

Read the cylinder as an instrument, not a decoration

Suppose the initial meniscus is recorded as 41.0 cm³ and the final meniscus as 50.8 cm³ after the metal is fully submerged. The displaced volume is 50.8 − 41.0 = 9.8 cm³. This is a difference of readings from the same scale. It is not the final reading, not the initial reading and not the water volume alone. A pupil who writes ‘50.8 cm³’ as the sample volume may still obtain a tidy division, but that division answers a different question.

Check the viewing procedure before trusting subtraction. For an appropriate water meniscus, read at eye level using the specified reference point. Avoid looking down from above. If the sample is wedged partly above the surface, the water increase represents only the submerged part. If a bubble rides under the sample, the increase counts the bubble as part of the displaced space and can make the calculated density too small. If water spills, the final reading no longer measures what you think it measures. A fair description should say which limitations were checked, not just say ‘careful measurements were taken’.

Use the formula with quantities that belong together

With a sample mass of 78.4 g and a displaced volume of 9.8 cm³, density = 78.4 ÷ 9.8 = 8.0 g/cm³. The unit is grams per cubic centimetre. The phrase ‘grams per centimetre’ would represent mass per length, and ‘g/cm²’ would represent mass per area; neither is the density found here. A student should put the unit next to the final result before comparing it with any chart.

The calculation assumes that the balance reading has already excluded any container or holder. If the object rests in a container whose mass is 12 g and the balance displays 90.4 g for both together, the sample’s mass is 90.4 − 12.0 = 78.4 g. Dividing 90.4 by 9.8 would give approximately 9.22 g/cm³, which could explain the draft’s false 9.2. It is arithmetically possible and scientifically wrong. Good auditing often identifies how a mistaken answer arose; this makes the correction reproducible rather than merely authoritative.

Reconcile the table and graph separately

Suppose the class also uses several samples of similar material with different measured volumes. A graph plots displayed mass on the vertical axis against sample volume on the horizontal axis. In a hypothetical calibration demonstration, volumes of 5.0 and 10.0 cm³ produce display readings of 52.0 and 92.0 g because a 12.0 g holder is included. The gradient is (92.0 − 52.0) ÷ (10.0 − 5.0) = 8.0 g/cm³. The intercept would be 12.0 g for an ideal straight-line model.

Why not calculate 92.0 ÷ 10.0? Because that would include the fixed holder. The gradient compares a change in mass with a change in volume; the holder cancels. The ratio of a single displayed reading to a single volume need not equal the gradient when the graph does not pass through the origin. Graphs are especially useful because this difference is visible. Yet a straight line alone does not prove composition. The calibration may be good within the tested range while the identity claim remains unsupported.

Disagreement is not a reason to choose your favourite number

Suppose a second learner reports 78.4 g divided by 10.8 cm³, giving about 7.26 g/cm³. Before averaging 8.00 and 7.26, compare the methods. Did the second attempt retain a bubble? Was it a different cylinder? Did the sample remain completely submerged? A bubble occupying extra space could enlarge the apparent displaced volume and lower the resulting calculated density. Averaging invalid readings with valid readings can make an answer look more objective while weakening its basis.

A third learner reports 8.9 g/cm³ from a smaller apparent displacement. That figure might indicate water loss, misreading or a legitimate difference in the measured sample. Its magnitude does not diagnose the cause by itself. The correct investigative response is to inspect records and repeat measurements under controlled conditions. A claim of ‘consistent results’ should not be accepted until the actual spread, resolution and method are shown. An audit is a process of resolving causes, not a vote among numbers.

Check arithmetic independently of the narrative

Do the division a second way. Because 9.8 × 8 = 78.4, the answer 8.0 is exactly consistent with the stated decimal inputs. A quick estimation check also helps: 80 divided by 10 is about 8. If a candidate’s calculator gives 80.0 or 0.8, that is a signal to inspect decimal placement. Where the question requests a given accuracy, present the answer accordingly rather than copying all digits displayed by the calculator.

The graph calculation should be independently recomputed. The difference in displayed masses is 40.0 g; the difference in volumes is 5.0 cm³; the gradient is 8.0 g/cm³. If a student chooses 92 and 52 in the wrong order while keeping the volume difference positive, the result becomes negative, which makes no physical sense for the density of this object. This kind of sign check is a low-cost safeguard. It is not a substitute for correct reasoning, but it catches one family of errors quickly.

Why the phrase ‘pure metal’ is still too strong

Density can help assess whether a result is compatible with a proposed material, provided the measurement is dependable and a suitable reference is given. It cannot, on its own, prove that an irregular object is chemically pure or uniquely identify an element. Different materials and mixtures can have similar bulk densities. Internal cavities, coatings, porosity and experimental errors can also change an apparent density. An honest caption might say ‘The measured density was approximately 8.0 g/cm³ under the conditions tested.’ That is informative without claiming more than the test establishes.

The exhibit might have additional chemical or historical evidence outside this exercise. If so, that evidence needs a separately documented owner. Do not present it as though the water-displacement calculation supplied it. In a Science response, this distinction separates explanation of a physical quantity from unsupported identification. In an English response, it separates careful wording from an overconfident assertion. A practical learner should be able to produce a defensible sentence even when an authority figure prefers a more dramatic one.

Accuracy, precision and repeatability are different questions

Accuracy concerns closeness to an appropriate accepted or reference value. Precision concerns how closely repeated measurements agree with one another. Repeatability asks whether the same method under comparable conditions produces consistent results. A narrow spread can be precise while centred on a wrong value if the apparatus has a systematic offset. A single reading does not justify a numerical percentage of accuracy. The caption’s ‘97% accurate’ needs an explicit definition, reference and calculation before it can be published.

If three repeat density estimates are 7.9, 8.0 and 8.1 g/cm³, the results cluster around 8.0. Their arithmetic mean is 8.0, and the range is 0.2 g/cm³. That describes observed agreement, not automatically absolute accuracy. If a calibration error consistently adds 1.0 g to every mass reading, the results may remain close together while biased. The safe public wording states what was measured and how, and invites readers to understand the limitation rather than hiding it behind a confidence-sounding number.

Write a caption that retains meaning after compression

A visitor may read a museum label for only a few seconds. The writer must therefore select, not merely shorten. Include the sample, method, result and limit. For example: ‘This irregular sample had a measured mass of 78.4 g. When submerged, it displaced 9.8 cm³ of water, giving an estimated density of 8.0 g/cm³. The measurement does not identify the sample’s composition on its own.’ Every sentence has a clear job. The label is brief enough to scan and complete enough to avoid misleading.

Compare a weaker version: ‘We tested a sample and proved its true density was 8.0.’ That sentence leaves out the method, overstates certainty, and uses ‘true’ where the evidence only supports an estimate. A longer caption is not necessarily better; a shorter caption is not necessarily clearer. What matters is whether the reader can distinguish the observation from its interpretation. Technical writing gains force from visible limits, not from adjectives such as ‘amazing’, ‘perfect’ or ‘definitive’.

The grammar check belongs after the facts, not instead of them

Review every number agreement, verb tense and comparison. ‘Each cylinders contain’ becomes ‘Each cylinder contains’. ‘The experiment was perform yesterday’ becomes ‘was performed’. If one set of readings is more reliable than another, say why; ‘more better’ is not a standard comparative form. But grammar is not a licence to change the data. The sentence ‘The sample displaced 9.8 cm³’ must not become ‘The samples displace 9.8 cm³’ unless there were genuinely several samples and the meaning remains correct.

A good editing pass has two separate questions. Is this sentence structurally correct English? Is the claim factually justified by the evidence record? A grammatically perfect false claim remains false. A correct calculation in an ungrammatical sentence may be difficult to interpret. Volume 1161 explains the mechanics of editing in greater depth; here the task is to protect both correctness and meaning during final publication.

When words suggest a certainty the experiment did not earn

The word ‘shows’ may be suitable when a figure really displays a pattern. The word ‘suggests’ may be suitable when an interpretation is plausible but not decisive. ‘Proves’ is much stronger and should not be used as a substitute for evidence. Words such as ‘always’, ‘never’, ‘only’ and ‘every’ create universal claims. A test on one specimen cannot establish what will happen to every specimen in every condition. The caption should match the range of observations, even if the cautious sentence sounds less exciting.

It also matters who the label is for. A younger visitor needs familiar language and a simple explanation of density; a Secondary Science learner may expect the equation and units. Both audiences deserve accurate claims. You can write ‘Density tells us how much mass is packed into a given volume’ as a teaching bridge, followed by the recorded figures. Avoid a misleading simplification such as ‘heavy materials are always denser’, since the relation depends on volume.

Decide whether the display is ready

An approval decision can have three outcomes. Release when the calculation, evidence and words are consistent. Release with a stated limitation when the evidence supports a narrower claim than the draft. Hold when a central measurement is missing, contradictory or unverified. The verdict should be linked to an action, not used as a vague label. ‘Hold until the container mass is subtracted and a valid displacement run is documented’ tells the next learner what to repair.

In this fictional case, the raw 78.4 g mass and 9.8 cm³ displacement support a density estimate of 8.0 g/cm³, provided the original apparatus checks pass. The separate graph’s gradient is compatible with that figure after the 12.0 g holder is accounted for. The headline ‘pure iron’ and ‘97% accurate’ do not follow from the given evidence. The reasoned verdict is to correct the caption and withhold the unsupported material-identification and accuracy claims, not to declare the entire science display unusable.

Worked case 1: the holder that masqueraded as the specimen

The catalogue gives a holder mass of 12.0 g, a combined display mass of 90.4 g and a displacement of 9.8 cm³. Step one: subtract 12.0 from 90.4 to find the object’s mass, 78.4 g. Step two: divide 78.4 by 9.8 to obtain 8.0 g/cm³. Step three: explain why 90.4 ÷ 9.8 is inappropriate: the holder was not the object that entered the cylinder. Step four: state the practical correction: record either the tared balance reading or the separately measured holder mass alongside the object measurement. This case teaches that numerical inputs must refer to the same physical object.

Worked case 2: a misleading graph caption

A draft says, ‘The graph proves all specimens have the same density because the points form a perfect straight line.’ A suitable examination response would first identify the measured pattern: a relation between displayed mass and volume over the tested points. It would then distinguish a model from a universal statement. Even if the plotted line is straight, the data may be few, affected by measurement uncertainty or restricted to one sample group. The improved sentence is: ‘Across the tested specimens, displayed mass increased approximately linearly with volume. The estimated gradient was 8.0 g/cm³ after accounting for a fixed holder mass.’

Worked case 3: a bubble changes the conclusion

A student obtains the same 78.4 g mass but reads 10.8 cm³ displacement because a trapped bubble was included in the submerged volume. The calculated density is about 7.26 g/cm³. Relative to the valid 9.8 cm³ volume, the extra space makes the denominator too large and density too small. The best explanation names the direction of error, not simply ‘human error’. The follow-up is to remove the bubble safely and repeat the immersion under the teacher’s instructions. Do not average the two runs before resolving the procedural difference.

Worked case 4: the claim of 97% accuracy

A caption says that the result is ‘97% accurate’ but supplies no accepted density, reference method or definition. The correct action is not to derive 97 from the range or from three repeats. Ask what reference was used and how the percentage was calculated. If there is no valid answer, remove the claim. If a formal uncertainty statement becomes available, explain it in the form relevant to that method rather than translating it into a vague promotional percentage. A public reader cannot audit a number whose denominator has been hidden.

Worked case 5: a result with two units

The draft alternates between 8.0 g/cm³ and 8000 kg/m³. These are equivalent: 1 g equals 0.001 kg, while 1 cm³ equals 0.000001 m³, so the conversion factor is 1000. The audit should retain a consistent primary unit for the intended readership and may include the equivalent SI expression. It must not print 8.0 kg/m³ as a casual conversion. The exercise checks dimensional reasoning: both numerator and denominator change when a compound unit is converted.

Worked case 6: the correct graph, wrong conclusion

Four recorded points fit the line ‘displayed mass = 8 × volume + 12’ in the chosen laboratory units. The graph supports a fixed offset and a gradient of 8. The offset may correspond to a holder, but the graph alone cannot prove the physical cause of that offset. The learner checks the equipment log for the independently recorded 12 g holder. If it is present, the interpretation is supported. Without it, the graph reveals a systematic intercept to investigate. Good science moves from a mathematical pattern to a physical explanation through evidence, not by declaring that every intercept is a tare.

Worked case 7: an overconfident comparison

A student compares sample A at 8.0 g/cm³ with sample B at 8.1 g/cm³ and writes that B is ‘definitely a different metal’. This conclusion ignores the readings’ resolution, method and possible uncertainty. The defensible statement is that B has a slightly higher estimated density in the reported measurements. Whether the difference is meaningful requires further checks. One-tenth of a gram per cubic centimetre may be smaller than the combined uncertainty, especially when a small cylinder displacement is involved. The audit should distinguish an observed numerical difference from a justified material-classification decision.

Worked case 8: the public summary

A parent asks for a single sentence suitable for the display’s opening paragraph. A useful answer is: ‘Students estimated the density of an irregular metal sample using mass and water displacement, then checked whether the graph and explanation agreed.’ This sentence names the experiment and the intellectual achievement without pretending that visitors need every numerical step in the opening line. The measurement table immediately below may supply 78.4 g, 9.8 cm³ and 8.0 g/cm³. The reader can then move from overview to evidence in the natural order.

Practice set: solve, explain and make a decision

Clinic 1: The water starts at 33.4 cm³ and ends at 44.6 cm³; sample mass is 89.6 g.

The displacement is 11.2 cm³ and density is 89.6 ÷ 11.2 = 8.0 g/cm³. Record both operations. Explain that the final reading itself is not the object’s volume. If the object was only partly submerged or the meniscus was read inconsistently, the mathematical steps would not guarantee a valid result.

For exam practice, first make your own two-line answer without viewing the explanation. Then underline the quantity being discussed, check its unit, and ask whether the final claim is an observation, a calculation or an inference. If you disagree with the solution, locate the specific input or assumption that produces the disagreement. A correction is useful only when it repairs a traceable step.

Clinic 2: A sample mass is 96.0 g and displacement is 12.0 cm³, but the label gives 8.0 g/mL as the density.

The magnitude is correct because 1 mL of volume equals 1 cm³. The unit g/mL is equivalent to g/cm³. For the display, select one notation and define it once. The real mistake would be changing to g/m without adjusting dimensions.

Clinic 3: One trial records 12.0 cm³, another 13.0 cm³, and the second has a visible bubble.

Investigate and repeat the second run rather than averaging the volumes. A bubble can increase the apparent displaced volume. If mass is fixed, that biases the density estimate downward. State the direction and the condition, not a precise correction that has not been measured.

Clinic 4: The vertical axis reads ‘mass, g’ and the horizontal axis reads ‘volume, cm³’, but a caption calls the gradient ‘cm³/g’.

For mass divided by volume the gradient unit is g/cm³. The reciprocal unit would arise from plotting volume against mass. Always derive the unit from vertical quantity over horizontal quantity, then compare it with the quantity the sentence claims to represent.

Clinic 5: Two graph points are (4 cm³, 44 g) and (9 cm³, 84 g), and a holder is present.

The slope is (84 − 44) ÷ (9 − 4) = 40 ÷ 5 = 8 g/cm³. Extrapolation to zero volume gives 12 g. Check whether the holder was independently measured before naming it as the source of the intercept; the graph itself only establishes the arithmetic pattern.

Clinic 6: A student writes ‘The set of measurements were accurate.’

The grammatical head is ‘set’, singular in this construction, so ‘was’ is appropriate. The factual adjective ‘accurate’ remains unproved without reference information. A complete audit may correct the verb and separately replace ‘accurate’ with an evidence-supported description of agreement between repeated readings.

Clinic 7: Three repeats are 7.9, 8.0 and 8.1 g/cm³.

The mean is 8.0 g/cm³ and the range is 0.2 g/cm³. That describes the results’ centre and spread. It is not a quantified accuracy measure. Check the apparatus and method if the question asks whether the measurements approach an accepted value.

Clinic 8: The caption says ‘No possible material could share this density’.

Reject the absolute inference. Similar bulk densities do not establish identical composition, nor does one numerical property establish exclusivity. Revise to a statement of measured density and, if appropriate, say that identification would require additional evidence. The expression ‘no possible’ is not justified by this data set.

Clinic 9: The display labels the specimen as ‘perfectly uniform’ because the graph is straight.

A straight relation over tested points is not equivalent to a microscopic uniformity test or proof of chemical purity. Use the graph to estimate bulk density within the range measured. Name separately any composition or internal-structure tests actually completed before adding further claims.

Clinic 10: An editing correction makes ‘The samples weighs’ into ‘The sample weighs’, but the lab log lists five samples.

The grammar may now be superficially correct, but the correction changes the number of objects. The intended grammatical repair should instead be ‘The samples weigh’. Always preserve the underlying experimental record while repairing agreement.

Clinic 11: A team gives density as 8.000000 g/cm³ after reading the cylinder only to 0.1 cm³.

The calculator’s digits do not create measurement precision. Report an appropriate number of significant figures according to the question, measured resolution and assessment instructions. Avoid suggesting that the many trailing zeros are supported by the apparatus.

Clinic 12: The final visitor label must be limited to three sentences.

Sentence one identifies sample and method. Sentence two reports mass, displaced volume and the calculated density with units. Sentence three says that the single physical measurement does not establish chemical identity. This approach preserves the chain of evidence within a tight editorial limit.

A thirty-minute timed rehearsal

Use the first four minutes to scan the packet: measurement log, graph, draft caption and editing notes. Spend eight minutes checking the displacement and mass arithmetic, including units. Spend six minutes on the graph and tare interpretation. Use six minutes to assess unsupported certainty claims. In the final six minutes, write a corrected caption and a short approval verdict. This rehearsal is a study exercise, not an official allocation of SEC examination time. Adjust the intervals after your first attempt reveals whether arithmetic, reading or writing is the slowest step.

Mark your rehearsal with an explicit key. Award credit for recognising the initial and final volume readings, the 9.8 cm³ difference, the 8.0 g/cm³ density, the 12.0 g graph offset, the corrected grammar and the removal of unsupported identity and percentage-accuracy claims. If the arithmetic is right but the caption overstates the conclusion, do not record the task as fully mastered. If the wording is cautious but a basic subtraction is wrong, target the calculation before practising longer persuasive passages.

A seven-day improvement route

On day one, repeat Volume 1159’s displacement procedure on paper and label every measured quantity. On day two, reconstruct Volume 1160’s mass–volume line and explain the gradient and intercept without notes. On day three, revisit Volume 1161’s agreement and tense corrections in the context of the fictional label. On day four, audit a new data table using the three-column claim ledger. On day five, rewrite three different captions for a young reader, an examination marker and a science club audience.

On day six, complete the thirty-minute mixed rehearsal and diagnose errors by cause: incorrect reading, missing tare, unit confusion, untested inference or misleading grammar. On day seven, return only to the categories you missed, then finish with a fresh mixed question. A student who cannot yet explain why a result is defensible needs more foundation, not a faster timer. The goal is independent judgement that survives when the numbers, labels or context change.

Frequently asked questions

Is EMS a separate SEC subject? No. EMS is this learning series’ English–Mathematics–Science integration. Students sit the actual subjects and subject levels for which they are entered. Does a straight mass–volume graph prove an object’s material? No; it provides a relationship over the tested data. Can water displacement identify a pure metal? Not on its own. Does a bubble make a calculated density too high or too low? A trapped bubble that inflates the apparent displaced volume tends to make the calculated density too low, all else equal.

Should I average any two different answers? First inspect method validity and reasons for disagreement. What does a nonzero graph intercept mean? It indicates an offset in the model; its physical cause requires evidence. How many significant figures should I use? Follow the question and the relevant subject requirements, recognising the apparatus’s resolution. Where do I study grammar itself? The preceding editing guide owns the grammatical drills; this chapter applies them to scientific release decisions.

Next reading and official references

This case is complete when you can defend the words ‘release’, ‘revise’ or ‘hold’ with an observable reason. Read the displacement practical, the mass–volume graph and the editing notice as the three specialist foundations. For current codes and exam descriptions, consult SEAB’s 2027 G3 directory, the Physics K323 document, Mathematics K310 and English K300. The next chapter develops a distinct physics skill: using a plumb line and suspension points to locate the centre of gravity of an irregular plane lamina.

Small Group Tutorials

How to Perform in the new G3 SEC Examinations | Learner’s Guide Vol 1162 | EMS Density Museum Caption Release — Audit Displacement, Graphs and Grammar