Science Olympiad for International Schools: 24 Questions

Science Olympiad for International School Students: A Study Guide

Science learning becomes more meaningful when students can explain why something happens, test an idea and use evidence to solve unfamiliar problems. This guide helps students attending international and local schools practise those skills through 24 Science Olympiad practice questions with worked answers, a preparation roadmap and trustworthy subject resources.

The School Connect Olympiad (SCO) International Science Olympiad (ISO) has class-wise options from Classes 1 to 12. Different school systems use different names for grades and teach topics in different sequences, so match the learner’s actual level to the current 2026 ISO syllabus overview before beginning.

Strengthen your scientific reasoning with clear examples and class-wise study resources. Students in Egypt can also explore our Science Olympiad for Egyptian students.

Illustrated science learning design with a world map — School Connect Science Olympiad — learn and explore

What should international-school students learn for Science Olympiad?

The SCO International Science Olympiad (ISO) covers age-appropriate scientific understanding, application and reasoning. The exact mix of biology, chemistry, physics and general science changes with grade level. Choose the learning stage that matches your current understanding and school topics.

Learning stage	Science focus	Useful preparation
Early primary	Plants, animals, the body, materials, weather, safety	Observe, sort, name and explain simple everyday events
Upper primary	Food chains, electricity, states of matter, light, habitats	Predict, measure and explain the result of a fair test
Lower secondary	Cells, forces, energy, chemistry, ecosystems and data	Connect scientific principles to diagrams and calculations
Senior secondary	Deeper physics, chemistry, biology and scientific analysis	Use equations, interpret evidence and justify assumptions

Use the official 2026 ISO syllabus overview to identify current subject direction, then select the relevant class from the ISO exam resource page. International Baccalaureate, Cambridge, CBSE, national and other curricula may introduce topics in a different order. Your school textbook remains an important primary reference.

How to practise scientific reasoning

Describe the question: identify what is being observed, compared or calculated.
Recall the relevant idea: choose a scientific principle such as energy transfer, the water cycle or conservation of matter.
Use evidence: read the graph, measurement, experiment conditions or units carefully.
Choose and explain: decide which option follows from the evidence and why the others do not.
Review errors: try a new example from the same topic rather than memorising an old answer letter.

24 Science Olympiad practice questions with worked answers

Choose a section suited to your class and try each question before checking the solution. Every question includes four choices and an explanation to help you understand the science behind the answer.

Primary learning — observation and living things

Question 1. Which plant part usually absorbs water and mineral nutrients from soil?
A. Roots | B. Petals | C. Seeds | D. Flowers
Answer: A. Roots. Roots take in water and dissolved mineral nutrients from the soil, supporting growth.
Question 2. Which sense organ is used to hear sounds?
A. Eye | B. Ear | C. Nose | D. Tongue
Answer: B. Ear. The ear receives sound vibrations and helps the brain interpret them as sound.
Question 3. Which is a living animal?
A. Pebble | B. Plastic cup | C. Butterfly | D. Metal key
Answer: C. Butterfly. A butterfly is an animal that grows, takes in food and responds to its surroundings.
Question 4. What is the change from liquid water to water vapour at the surface called?
A. Freezing | B. Condensation | C. Melting | D. Evaporation
Answer: D. Evaporation. Evaporation turns liquid water at its surface into water vapour, even below boiling temperature.
Question 5. Which tool measures the amount of rainfall?
A. Rain gauge | B. Thermometer | C. Weighing scale | D. Compass
Answer: A. Rain gauge. A rain gauge collects and measures precipitation, commonly reported in millimetres.
Question 6. Which material lets most visible light pass through clearly?
A. Wooden board | B. Clean transparent glass | C. Cardboard | D. Brick
Answer: B. Clean transparent glass. Clean transparent glass transmits most visible light and lets objects behind it be seen clearly.

Upper primary — systems, energy and changes

Question 7. Which order is a possible simple food chain?
A. Frog → grasshopper → grass | B. Grasshopper → frog → grass | C. Grass → grasshopper → frog | D. Grass → frog → grasshopper
Answer: C. Grass → grasshopper → frog. Grass makes food through photosynthesis. A grasshopper can eat grass, and a frog can eat grasshoppers.
Question 8. Which object is most likely to be attracted strongly to a common magnet?
A. Wooden ruler | B. Paper sheet | C. Plastic spoon | D. Iron nail
Answer: D. Iron nail. Iron is a ferromagnetic material and is strongly attracted to common permanent magnets.
Question 9. What is needed for a simple battery-and-bulb circuit to light the bulb?
A. A complete conducting path | B. Only one connected bulb terminal | C. An open gap in the circuit | D. A dry paper strip instead of wire
Answer: A. A complete conducting path. A complete conducting loop from one battery terminal through the bulb and back allows current to flow.
Question 10. Why does an opaque object cast a shadow?
A. It creates new darkness | B. It blocks some light reaching a surface | C. It bends all sunlight into the ground | D. It produces its own light
Answer: B. It blocks some light reaching a surface. An opaque object blocks light travelling towards a surface, leaving a region that receives less illumination.
Question 11. Which is a physical change that can normally be reversed?
A. Burning wood | B. Cooking an egg | C. Melting clean ice | D. Rusting iron
Answer: C. Melting clean ice. Melting ice changes water from solid to liquid, and the water can freeze again.
Question 12. Which action helps reduce soil erosion on a bare slope?
A. Removing all plants | B. Pouring salt on the ground | C. Making the soil completely loose | D. Planting vegetation with roots
Answer: D. Planting vegetation with roots. Plant roots help hold soil in place, reducing how readily rain and wind carry it away.

Secondary-level Science Olympiad questions

Lower secondary — evidence and calculations

Question 13. A net force of 6 N acts on a 2 kg object. What is its acceleration?
A. 3 m/s² | B. 2 m/s² | C. 6 m/s² | D. 12 m/s²
Answer: A. 3 m/s². Newton’s second law gives a = F/m = 6 N ÷ 2 kg = 3 m/s².
Question 14. A solid has a mass of 180 g and a volume of 60 cm³. What is its density?
A. 2 g/cm³ | B. 3 g/cm³ | C. 6 g/cm³ | D. 12 g/cm³
Answer: B. 3 g/cm³. Density is mass divided by volume. Here 180/60 = 3 grams per cubic centimetre.
Question 15. An aqueous solution has pH 4. How is it usually described?
A. Basic | B. Neutral | C. Acidic | D. Pure water
Answer: C. Acidic. Under common classroom conditions, an aqueous solution with pH below 7 is acidic.
Question 16. Which gas is released by green plants during oxygen-producing photosynthesis?
A. Nitrogen | B. Hydrogen | C. Carbon dioxide | D. Oxygen
Answer: D. Oxygen. Oxygen is produced during oxygenic photosynthesis when water molecules are split in the light-dependent reactions.
Question 17. What does an enzyme usually do in a biological reaction?
A. Speed up the reaction without being permanently consumed | B. Increase the final amount of matter | C. Always make a reaction hot | D. Turn every reaction into photosynthesis
Answer: A. Speed up the reaction without being permanently consumed. Enzymes act as biological catalysts, usually lowering activation energy and remaining available for further reactions.
Question 18. A resistor of 4 Ω is connected across 12 V. What current flows, assuming it obeys Ohm’s law?
A. 2 A | B. 3 A | C. 4 A | D. 48 A
Answer: B. 3 A. Ohm’s law gives I=V/R=12/4=3 amperes.

Senior secondary — science applications

Question 19. How many moles are in 36 g of water (molar mass 18 g/mol)?
A. 1 mol | B. 3 mol | C. 2 mol | D. 18 mol
Answer: C. 2 mol. Number of moles = mass ÷ molar mass = 36 ÷ 18 = 2 mol.
Question 20. Two carriers for a recessive allele (Aa × Aa) have a child. What is the probability of genotype aa, assuming Mendelian segregation?
A. 1/2 | B. 3/4 | C. 1/8 | D. 1/4
Answer: D. 1/4. The four equally likely genotype combinations are AA, Aa, Aa and aa. Exactly one is aa, so the probability is 1/4.
Question 21. A radioactive sample has a half-life of 5 days. What fraction remains after 10 days?
A. 1/4 | B. 1/3 | C. 1/2 | D. 1/8
Answer: A. 1/4. Ten days is two half-lives. The remaining fraction is (1/2)² = 1/4.
Question 22. What is the kinetic energy of a 2 kg object travelling at 3 m/s?
A. 3 J | B. 9 J | C. 6 J | D. 18 J
Answer: B. 9 J. Kinetic energy = 1/2 mv² = 1/2 × 2 × 3² = 9 joules.
Question 23. A wave moves at 300 m/s with frequency 50 Hz. What is its wavelength?
A. 3 m | B. 5 m | C. 6 m | D. 15 m
Answer: C. 6 m. Wavelength λ=v/f=300/50=6 metres.
Question 24. For many chemical reactions, why does increasing temperature generally increase reaction rate?
A. Molecules always become heavier | B. Atoms disappear from the mixture | C. The reactants change into elements | D. More collisions have enough energy to overcome the activation barrier
Answer: D. More collisions have enough energy to overcome the activation barrier. At higher temperature, a larger fraction of molecular collisions has enough energy to react, although individual reactions can have additional limitations.

A four-week Science Olympiad preparation plan

Week	Learning goal	Try this
1	Understand the chosen class syllabus	Read the topic list, check school chapters and attempt a few diagnostic questions
2	Build foundations	Study the weakest biology, chemistry, physics or general-science concepts with explanatory examples
3	Apply methods	Use graphs, measurements and scenario questions; review why incorrect options are wrong
4	Practise and review	Try a timed question set, review the mistakes and refine your exam preparation

Three simple activities to develop scientific thinking

1. Compare how fast equal amounts of ice melt

Place equal-sized ice cubes in two shallow bowls in the same room, away from electrical items. Put one bowl on a shaded table and one in a warmer spot without direct flame or hazardous heat. Record the time until each ice cube melts. Keep starting cube size and bowl type as similar as possible and repeat the test before drawing a conclusion.

2. Test the effect of distance on a shadow

Use a torch, a ruler and one opaque object. Keep the torch fixed while moving the object to three measured positions. Record the shadow length on a sheet of paper. Ask which variables stayed constant and which changed. Do not shine a bright torch into anyone’s eyes.

3. Explain a result using evidence

After either activity, write four short lines: question → prediction → observation → explanation. Make the explanation agree with what was measured. Science values repeatable evidence, not only a correct-sounding answer.

Science Olympiad Study Material for Classes 1–12

Explore science questions and learning resources for your class. Practise important concepts, strengthen your understanding with worked examples, and move to more challenging questions as your confidence improves.

Science Olympiad Syllabus, Exam Dates and Registration

Prepare for the School Connect Olympiad International Science Olympiad with the 2026 Science Olympiad syllabus and exam preparation guide. Check the exam calendar and registration details when planning your participation.

Use the class-wise resources above for additional science practice, and pair them with the learning chapters and exam topics relevant to your grade.

Science Olympiad: Frequently Asked Questions

Can students from different school curricula use these Science Olympiad resources?

Yes. Students following Cambridge, IB, CBSE and national curricula can practise scientific concepts, observation and problem-solving at an appropriate level. Select the class and topic that best suit your school learning.

How can I choose the right Science Olympiad level?

Begin with your current class and the Science Olympiad syllabus. Revise the key concepts, practise class-wise questions and gradually attempt more challenging problems.

Where can I find Science Olympiad questions for my class?

Use the Class 1–12 resource links above to explore science questions and learning material for your level.

How can I make the most of the 24 practice questions?

Attempt the questions without looking at the answers, then read the explanations. Note which topics you found difficult and practise a few more questions that use the same scientific principle.

Where can I find the exam pattern and duration?

The SCO Science Olympiad exam guide provides preparation information. Use your registration and exam instructions to confirm the details for your chosen session.

What certificates and awards are available?

Visit the School Connect Olympiad awards page for participation certificates, achievement recognition and the relevant eligibility conditions.

Can students study science at home without laboratory equipment?

Yes. Reading scientific diagrams, observing natural phenomena, practising numerical questions and completing safe supervised activities help build understanding.

Where can students in Egypt find additional Science Olympiad guidance?

Students and families in Egypt can explore our Science Olympiad preparation guide for Egypt alongside these class-wise questions.

Keep exploring: Select your class from the resources above, practise one topic at a time and use the SCO International Science Olympiad subject pages to plan your next learning session.