Year 9 science questions with answers: biology, chemistry, physics, and Earth and space

Each daily paper has 8 original questions worth 25 to 35 marks. The biology, chemistry and physics papers each practise one strand, and each has some topics from other years; the strand sections below say which questions to sit. There is also a mixed Year 9 Science paper with all three in one. No paper covers Earth and space science on its own, so use the carbon cycle question on this page.

What's in Year 9 science

These four make up the Science understanding strand. The other two strands, Science as a human endeavour and Science inquiry, run through all of them: planning fair investigations, handling data and errors, and peer review. In NSW, Year 9 follows the Science 7 to 10 Syllabus (2023), which public schools start teaching to Year 9 in 2026. There is no state-wide Year 9 science exam: your school sets its own tests.

We wrote the questions below for this page. Try each one before you read the answer.

Year 9 science biology: body systems and reproduction

The daily Year 9 Science: Biology paper fits in its heart and blood, digestion, nervous system and homeostasis questions, and its photosynthesis and respiration questions support the carbon cycle. Its inheritance questions are Year 10 work, and its cells and microscopy questions revise Years 7 and 8.

1. Negative feedback. After a meal, blood glucose rises. Describe how the body brings it back down. Answer: the pancreas detects the rise and releases the hormone insulin. Insulin travels in the blood to the liver and muscles, which absorb glucose from the blood and convert it to glycogen for storage, so the level falls. As it returns to normal, less insulin is released. The response reverses the change, which is what makes it negative feedback.

2. Sexual and asexual reproduction. Strawberry plants spread by runners and also make seeds. Give one advantage of each. Answer: runners are asexual: fast, need only one parent, and copy a plant that already suits the conditions. Seeds come from sexual reproduction: the offspring vary, so some are more likely to survive if the environment changes or a disease arrives.

Year 9 science chemistry: atoms, decay and equations

The daily Year 9 Science: Chemistry paper fits in its atomic structure, fuels and combustion, and atmosphere questions, and in any balanced equation. Its periodic table and rates of reaction questions are Year 10 work; its states of matter and separating mixtures questions revise Years 7 and 8. The physics paper's atomic structure and radiation questions fit this strand too.

3. Models of the atom. Put these in order and say what each discovery changed: Rutherford's gold foil experiment, Thomson's discovery of the electron, Chadwick's discovery of the neutron. Answer: Thomson (1897) showed atoms contain small negative electrons, giving the plum pudding model. Rutherford (1911) found most alpha particles pass straight through gold foil but a few bounce back, so the positive charge and mass sit in a tiny nucleus. Chadwick (1932) found the neutron, explaining why nuclei are heavier than their protons alone.

Review atomic structure in our Atomic Structure course, then press Mark.

4. Conservation of mass. Methane burns in oxygen: CH₄ + 2O₂ → CO₂ + 2H₂O. 16 g of methane reacts with 64 g of oxygen and makes 44 g of carbon dioxide. What mass of water forms? Answer: mass is conserved, so the products also total 16 + 64 = 80 g, and the water is 80 − 44 = 36 g. Count the atoms to check the balance: 1 C, 4 H and 4 O on each side. Try others in the Equation Balancer.

Year 9 science physics: energy and waves

The daily Year 9 Science: Physics paper fits in its energy stores and transfers, power and efficiency, waves, and density and states of matter questions. Skip its speed, forces and motion questions (Year 10), and its circuits and magnets questions.

5. Efficiency. A solar panel receives 1000 J of light energy each second and delivers 200 J of electrical energy. What is its efficiency, and where does the rest go? Answer: efficiency = useful output ÷ total input × 100% = 200 ÷ 1000 × 100% = 20%. Energy is conserved: the other 800 J is reflected or heats the panel and its surroundings.

6. Wave and particle models. A sound wave has frequency 170 Hz and travels at 340 m/s. Find its wavelength, and explain why sound can't cross a vacuum but light can. Answer: v = fλ, so λ = 340 ÷ 170 = 2.0 m. Sound is passed on by particles bumping into each other, so it needs a medium; light is an electromagnetic wave, which needs no particles, so it crosses empty space. Check wave sums with the Wave Speed Calculator.

Here x is the distance along the wave in metres and y is the displacement. Crest to crest is one wavelength.

Earth and space science: the carbon cycle

7. Carbon between the spheres. Name one process that moves carbon from the atmosphere into the biosphere, one that returns it, and one that releases carbon stored in the geosphere. Answer: photosynthesis takes carbon dioxide from the atmosphere into plants. Respiration by plants, animals and decomposers returns it. Combustion of fossil fuels releases carbon locked in the geosphere for millions of years, which is why burning them raises the carbon dioxide in the atmosphere.

Use the daily papers as a practice test

1. Pick the paper for the strand you are revising and work to the suggested time, about 30 to 40 minutes.
2. Skip the questions from other years listed in that strand's section above.
3. Write the equation, the numbers with units, and the answer with its unit.
4. Mark it, note which strand each lost mark belongs to, and use the carbon cycle question here for Earth and space science.

Common Year 9 science mistakes

• Saying energy is used up. It is transferred or transformed; efficiency measures how much ends up useful.
• Changing small numbers in a formula to balance an equation. Only change the big numbers in front.
• Mixing up insulin and glucagon. Insulin lowers blood glucose; glucagon raises it.
• Thinking sound travels through space. It needs particles; light doesn't.
• Calling the plum pudding model wrong without saying why. Say which evidence replaced it: the gold foil results.

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