IS1 - Energy systems and climate

QUESTION 1 8 marks Criterion A

Hard

Scientific understanding: Energy transfers and efficiency

A school replaces filament lamps with LEDs. Use integrated scientific understanding to explain the situation.

a. Explain the scientific principle that applies in this context.

[3]

b. State a relevant scientific relationship or equation.

[2]

c. Apply the principle to the situation and connect two science disciplines.

[3]

Show complete worked solution

(a)

Useful efficiency is the useful energy output divided by total energy input. Energy is conserved, but some is transferred to less useful thermal stores.

(b)

The relevant relationship is \(\eta=\frac{E_{useful}}{E_{input}}\times100\%\).

(c)

An LED producing the same light with less electrical input transfers less energy as unwanted heating.

Physics quantifies the transfers; environmental science considers the emissions associated with generating the electricity.

QUESTION 2 11 marks Criterion B

Hard

Inquiry design: Energy transfers and efficiency

Compare the electrical efficiency of three lamp types that provide similar illuminance.

a. Convert the aim into a focused research question with named variables.

[3]

b. Propose a sequence that collects enough valid evidence.

[5]

c. State the expected pattern and how it will be tested against the results.

[2]

d. Give the essential safety or ethical precaution.

[1]

Show complete worked solution

(a)

How does lamp type affect electrical energy used per unit useful light output under the stated conditions?

The independent variable is lamp type; the dependent variable is electrical energy used per unit useful light output.

(b)

Compare every named condition of lamp type with a matched baseline or control, using randomized or alternated trial order where possible. Measure electrical energy used per unit useful light output with a calibrated method at fixed intervals or a defined endpoint. Repeat every condition at least three times.

Keep constant illuminance at the sensor, lamp-to-sensor distance, supply voltage and test duration.

(c)

Expected pattern: Useful light energy is directly proportional to input energy and the efficiency remains about 30%.

Calculate a mean for each condition, show variation with a range or another suitable spread measure, and plot the dependent variable against the independent variable with units.

(d)

Do not touch hot lamps; use intact low-voltage apparatus.

QUESTION 3 9 marks Criterion C

Hard

Evidence analysis: Energy transfers and efficiency

The graph shows results from a focused investigation of energy transfers and efficiency.

a. Identify the pattern shown by all plotted points, including any plateau, optimum or anomaly.

[2]

b. Calculate the efficiency at an input of 240 J.

[3]

c. State a conclusion that is supported by the evidence without claiming more than the data show.

[2]

d. Explain why the evidence is not yet sufficient for a general conclusion.

[2]

Show complete worked solution

(a)

Useful light energy is directly proportional to input energy and the efficiency remains about 30%.

(b)

\[\eta=\frac{72}{240}\times100=\boxed{30.0\%}\]

(c)

Useful light energy is directly proportional to input energy and the efficiency remains about 30%. The conclusion applies only to the tested range and conditions.

(d)

Only light energy is counted as useful; the classification depends on the intended function.

QUESTION 4 8 marks Criterion D

Hard

Science in context: Energy transfers and efficiency

A council must choose between inexpensive filament lamps and costlier LEDs for street lighting.

a. Identify two affected groups or systems and explain how their interests may differ.

[3]

b. Evaluate the claim using scientific and societal considerations.

[3]

c. Recommend a transparent next step.

[2]

Show complete worked solution

(a)

Users or decision-makers may value that leds use less electricity for the same illumination and last longer. Nearby communities, workers or ecosystems may instead be most affected because manufacture and disposal require materials and energy, and poor light design can affect wildlife.

(b)

The benefit is scientifically plausible, but it does not by itself establish the best decision. Manufacture and disposal require materials and energy, and poor light design can affect wildlife. Cost, access, responsibility and reversibility must be considered with the scientific outcomes.

(c)

Compare lifetime energy use, failure rate, illumination quality, embodied impacts and total cost per operating hour.

QUESTION 1 8 marks Criterion A

Medium

Scientific understanding: Fuels, combustion and cellular respiration

A biofuel digester converts food waste into methane. Use integrated scientific understanding to explain the situation.

a. Write the relevant scientific relationship and explain how it supports the context.

[3]

b. Use scientific reasoning to predict the likely outcome.

[3]

c. Identify the contribution of two scientific disciplines.

[2]

Show complete worked solution

(a)

\[\mathrm{CH_4+2O_2\rightarrow CO_2+2H_2O}\]

Combustion and cellular respiration both transfer chemical energy through oxidation. Complete methane combustion forms carbon dioxide and water; anaerobic microbes can produce methane from organic matter.

(b)

Capturing methane for controlled combustion can recover energy and prevent direct release of a powerful greenhouse gas.

(c)

Chemistry describes oxidation, biology explains microbial digestion, and physics measures the energy transferred.

QUESTION 2 11 marks Criterion B

Hard

Inquiry design: Fuels, combustion and cellular respiration

Determine how digester temperature affects the initial methane-production rate.

a. Identify the independent and dependent variables and state a scientific hypothesis.

[3]

b. Describe the sampling or experimental procedure.

[4]

c. Explain how repetition and processing improve the evidence.

[2]

d. State the controls and one risk-control measure.

[2]

Show complete worked solution

(a)

Independent variable: digester temperature.

Dependent variable: methane volume produced per gram of feedstock per hour.

Hypothesis: Production increases to 40 °C and then falls sharply, consistent with an enzyme-controlled microbial process with an optimum.

(b)

Test at least five scientifically justified values of digester temperature across a safe range, including a baseline or control where possible. Measure methane volume produced per gram of feedstock per hour with a calibrated method at fixed intervals or a defined endpoint. Repeat every condition at least three times.

(c)

Calculate a mean for each condition, show variation with a range or another suitable spread measure, and plot the dependent variable against the independent variable with units.

(d)

Keep constant feedstock composition and mass, inoculum, pH, vessel volume and measurement interval.

Use small sealed systems with pressure relief; keep methane away from ignition sources.

QUESTION 3 10 marks Criterion C

Medium

Evidence analysis: Fuels, combustion and cellular respiration

The graph shows results from a focused investigation of fuels, combustion and cellular respiration.

a. Summarize the quantitative trend before calculating a key value.

[2]

b. Calculate the percentage decrease in rate from 40 °C to 50 °C.

[3]

c. Explain whether the dataset supports the proposed scientific interpretation.

[2]

d. Give one limitation and one precise next step.

[3]

Show complete worked solution

(a)

Production increases to 40 °C and then falls sharply, consistent with an enzyme-controlled microbial process with an optimum.

(b)

\[\frac{31-12}{31}\times100=\boxed{61.3\%}\]

(c)

Production increases to 40 °C and then falls sharply, consistent with an enzyme-controlled microbial process with an optimum. This supports the interpretation within the measured range, but does not by itself prove causation.

(d)

Four temperatures do not locate the precise optimum, and gas volume also changes with temperature.

Increase replication and resolution around important changes, check calibration, and measure the named confounding variables.

QUESTION 4 8 marks Criterion D

Medium

Science in context: Fuels, combustion and cellular respiration

A city is considering an anaerobic digester for separately collected food waste.

a. Explain one potential benefit using science.

[2]

b. Analyze a limitation, risk or unintended consequence.

[2]

c. Make a conditional recommendation and specify the evidence that should guide implementation.

[4]

Show complete worked solution

(a)

It can reduce landfill methane and produce usable fuel and nutrient-rich digestate.

(b)

Leaks, odour, contaminated feedstock and digestate management can reduce the benefit.

(c)

Proceed only if the expected benefit is demonstrated under local conditions and the identified risks can be controlled. Use measured leak rates, displaced fossil energy, life-cycle emissions, digestate quality and local collection data. The decision should be reviewed when monitoring data change.

QUESTION 1 8 marks Criterion A

Hard

Scientific understanding: Electricity generation, storage and distribution

A remote clinic combines solar panels with a battery. Use integrated scientific understanding to explain the situation.

a. Explain the scientific principle that applies in this context.

[3]

b. State a relevant scientific relationship or equation.

[2]

c. Apply the principle to the situation and connect two science disciplines.

[3]

Show complete worked solution

(a)

A generator converts one energy form to electrical energy, while a battery stores energy chemically. Power measures the rate of energy transfer.

(b)

The relevant relationship is \(E=Pt\).

(c)

The battery must store enough energy to bridge periods when panel output is below demand.

Physics describes power and circuits; chemistry explains electrochemical storage; health science identifies critical loads.

QUESTION 2 11 marks Criterion B

Hard

Inquiry design: Electricity generation, storage and distribution

Test how discharge current affects the usable capacity of a rechargeable battery.

a. State a directional hypothesis and the scientific reason for it.

[3]

b. Design a fair method, including a suitable range and measurement plan.

[5]

c. Explain how reliability, presentation and safety will be addressed.

[3]

Show complete worked solution

(a)

Hypothesis: Usable energy decreases as discharge current increases.

The prediction follows from this scientific principle: A generator converts one energy form to electrical energy, while a battery stores energy chemically. Power measures the rate of energy transfer.

(b)

Test at least five scientifically justified values of discharge current across a safe range, including a baseline or control where possible. Measure electrical energy delivered before the cutoff voltage with a calibrated method at fixed intervals or a defined endpoint. Repeat every condition at least three times.

Keep constant battery model and age, starting charge, temperature and cutoff voltage.

(c)

Calculate a mean for each condition, show variation with a range or another suitable spread measure, and plot the dependent variable against the independent variable with units.

Use a current limit, prevent short circuits and stop if the cell overheats or swells.

QUESTION 3 9 marks Criterion C

Hard

Evidence analysis: Electricity generation, storage and distribution

The graph shows results from a focused investigation of electricity generation, storage and distribution.

a. Identify the pattern shown by all plotted points, including any plateau, optimum or anomaly.

[2]

b. Calculate the percentage loss of usable energy between 0.5 A and 2.0 A.

[3]

c. State a conclusion that is supported by the evidence without claiming more than the data show.

[2]

d. Explain why the evidence is not yet sufficient for a general conclusion.

[2]

Show complete worked solution

(a)

Usable energy decreases as discharge current increases.

(b)

\[\frac{48-36}{48}\times100=\boxed{25.0\%}\]

(c)

Usable energy decreases as discharge current increases. The conclusion applies only to the tested range and conditions.

(d)

One battery was tested at each current, so cell-to-cell variation may be confused with the current effect.

QUESTION 4 8 marks Criterion D

Hard

Science in context: Electricity generation, storage and distribution

The clinic can buy a small lead-acid bank or a costlier lithium iron phosphate bank.

a. Identify two affected groups or systems and explain how their interests may differ.

[3]

b. Evaluate the claim using scientific and societal considerations.

[3]

c. Recommend a transparent next step.

[2]

Show complete worked solution

(a)

Users or decision-makers may value that lithium iron phosphate usually offers longer cycle life and greater usable depth of discharge. Nearby communities, workers or ecosystems may instead be most affected because up-front cost, electronic controls, mineral sourcing and end-of-life systems differ.

(b)

The benefit is scientifically plausible, but it does not by itself establish the best decision. Up-front cost, electronic controls, mineral sourcing and end-of-life systems differ. Cost, access, responsibility and reversibility must be considered with the scientific outcomes.

(c)

Compare verified cycle life, fire performance, usable kWh, local temperature behavior, warranty and recycling per lifetime kWh.

QUESTION 1 8 marks Criterion A

Medium

Scientific understanding: Greenhouse effect and climate evidence

Students compare atmospheric carbon dioxide and temperature records. Use integrated scientific understanding to explain the situation.

a. Write the relevant scientific relationship and explain how it supports the context.

[3]

b. Use scientific reasoning to predict the likely outcome.

[3]

c. Identify the contribution of two scientific disciplines.

[2]

Show complete worked solution

(a)

\[\Delta E=E_{in}-E_{out}\]

Greenhouse gases absorb and re-emit outgoing infrared radiation, reducing the rate at which energy leaves Earth at a given surface temperature.

(b)

A persistent positive energy imbalance raises the energy stored in oceans, land and atmosphere.

(c)

Molecular absorption is chemistry, radiation balance is physics, and carbon cycling involves biology and Earth science.

QUESTION 2 11 marks Criterion B

Medium

Inquiry design: Greenhouse effect and climate evidence

Use sealed model atmospheres to test how carbon dioxide concentration affects cooling rate.

a. Formulate a focused research question and a testable prediction.

[3]

b. Give a reproducible method and explain how the results will be processed.

[5]

c. Identify the main controls and manage the significant risk.

[3]

Show complete worked solution

(a)

Research question: How does carbon dioxide concentration affect temperature decrease over a fixed cooling interval under the stated conditions?

Prediction: Infrared absorption increases with carbon dioxide concentration, although the increments are not perfectly proportional.

(b)

Test at least five scientifically justified values of carbon dioxide concentration across a safe range, including a baseline or control where possible. Measure temperature decrease over a fixed cooling interval with a calibrated method at fixed intervals or a defined endpoint. Repeat every condition at least three times.

Calculate a mean for each condition, show variation with a range or another suitable spread measure, and plot the dependent variable against the independent variable with units.

(c)

Keep constant starting temperature, container, gas volume, lamp exposure, sensor position and room conditions.

Use safe gas sources and avoid pressurizing or tightly heating sealed containers.

QUESTION 3 10 marks Criterion C

Medium

Evidence analysis: Greenhouse effect and climate evidence

The graph shows results from a focused investigation of greenhouse effect and climate evidence.

a. Summarize the quantitative trend before calculating a key value.

[2]

b. Calculate the percentage increase in absorption from 280 ppm to 700 ppm.

[3]

c. Explain whether the dataset supports the proposed scientific interpretation.

[2]

d. Give one limitation and one precise next step.

[3]

Show complete worked solution

(a)

Infrared absorption increases with carbon dioxide concentration, although the increments are not perfectly proportional.

(b)

\[\frac{38-18}{18}\times100=\boxed{111\%}\]

(c)

Infrared absorption increases with carbon dioxide concentration, although the increments are not perfectly proportional. This supports the interpretation within the measured range, but does not by itself prove causation.

(d)

A classroom container does not reproduce atmospheric depth, convection, clouds or the full radiation spectrum.

Increase replication and resolution around important changes, check calibration, and measure the named confounding variables.

QUESTION 4 8 marks Criterion D

Hard

Science in context: Greenhouse effect and climate evidence

A coastal city must decide whether to fund flood defenses now or wait for more precise local projections.

a. Explain one potential benefit using science.

[2]

b. Analyze a limitation, risk or unintended consequence.

[2]

c. Make a conditional recommendation and specify the evidence that should guide implementation.

[4]

Show complete worked solution

(a)

Early adaptation can reduce future damage and protect vulnerable infrastructure.

(b)

Large investments may be misplaced if local change differs from projections or designs lock in poor choices.

(c)

Proceed only if the expected benefit is demonstrated under local conditions and the identified risks can be controlled. Use multiple climate models, observed sea-level trends, uncertainty ranges, asset lifetimes and staged designs that can be upgraded. The decision should be reviewed when monitoring data change.

QUESTION 1 8 marks Criterion A

Medium

Scientific understanding: Evaluating energy technologies and choices

A community compares wind, rooftop solar and a gas generator. Use integrated scientific understanding to explain the situation.

a. Explain the scientific principle that applies in this context.

[3]

b. State a relevant scientific relationship or equation.

[2]

c. Apply the principle to the situation and connect two science disciplines.

[3]

Show complete worked solution

(a)

Energy technologies must be compared by delivered service over time, including capacity factor, efficiency, storage, emissions and reliability.

(b)

The relevant relationship is \(E_{annual}=P_{rated}\times8760\times f\).

(c)

A lower-rated source can deliver more annual energy if its capacity factor is higher.

Physics quantifies output, chemistry and Earth science address fuels and materials, and biology helps assess ecological effects.

QUESTION 2 11 marks Criterion B

Hard

Inquiry design: Evaluating energy technologies and choices

Compare actual and rated output of small renewable generators at the school.

a. Write the research question and justify a control or baseline condition.

[3]

b. Describe how the variables will be changed, measured and controlled.

[5]

c. State the prediction, data treatment and safety provision.

[3]

Show complete worked solution

(a)

How does technology and environmental condition affect electrical energy delivered per day under the stated conditions?

A baseline or control shows the response without the tested change, so an observed difference can be attributed more confidently to technology and environmental condition.

(b)

Compare every named condition of technology and environmental condition with a matched baseline or control, using randomized or alternated trial order where possible. Measure electrical energy delivered per day with a calibrated method at fixed intervals or a defined endpoint. Repeat every condition at least three times.

Keep constant measurement calibration, recording interval and load connection.

(c)

Prediction: Output varies substantially between days, showing why storage or a complementary source may be required.

Calculate a mean for each condition, show variation with a range or another suitable spread measure, and plot the dependent variable against the independent variable with units.

Use qualified electrical installation and do not access turbines or rooftops during measurements.

QUESTION 3 9 marks Criterion C

Hard

Evidence analysis: Evaluating energy technologies and choices

The graph shows results from a focused investigation of evaluating energy technologies and choices.

a. Identify the pattern shown by all plotted points, including any plateau, optimum or anomaly.

[2]

b. Calculate the mean daily solar energy.

[3]

c. State a conclusion that is supported by the evidence without claiming more than the data show.

[2]

d. Explain why the evidence is not yet sufficient for a general conclusion.

[2]

Show complete worked solution

(a)

Output varies substantially between days, showing why storage or a complementary source may be required.

(b)

\[\bar E=\frac{18+27+12+23}{4}=\boxed{20.0\ \mathrm{kWh}}\]

(c)

Output varies substantially between days, showing why storage or a complementary source may be required. The conclusion applies only to the tested range and conditions.

(d)

Four days do not represent seasonal performance.

QUESTION 4 8 marks Criterion D

Hard

Science in context: Evaluating energy technologies and choices

The community must choose a resilient electricity system for a cyclone-prone island.

a. Identify two affected groups or systems and explain how their interests may differ.

[3]

b. Evaluate the claim using scientific and societal considerations.

[3]

c. Recommend a transparent next step.

[2]

Show complete worked solution

(a)

Users or decision-makers may value that a distributed renewable microgrid can reduce imported fuel use and isolate faults. Nearby communities, workers or ecosystems may instead be most affected because storm damage, intermittent output, battery replacement and technician availability may limit reliability.

(b)

The benefit is scientifically plausible, but it does not by itself establish the best decision. Storm damage, intermittent output, battery replacement and technician availability may limit reliability. Cost, access, responsibility and reversibility must be considered with the scientific outcomes.

(c)

Model hourly demand and weather over years, test cyclone ratings, include maintenance logistics and compare lifetime cost and emissions.

IS1 - Energy systems and climate

IS1.1 - Energy transfers and efficiency 4 questions

IS1.2 - Fuels, combustion and cellular respiration 4 questions

IS1.3 - Electricity generation, storage and distribution 4 questions

IS1.4 - Greenhouse effect and climate evidence 4 questions

IS1.5 - Evaluating energy technologies and choices 4 questions