SOF NSO
SOF International Science Olympiad (ISO)
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Cheat sheet
Keep the key ideas within reach.
ExploreKey terms
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ExploreStudy plan
Give each week a clear focus.
ExploreCommon mistakes
Understand the traps and how to avoid them.
ExploreCase studies
Put your knowledge to work in context.
ExploreExam-day guide
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ExploreAbout this exam
The International Science Olympiad (SOF ISO) is an annual academic competition run by the Science Olympiad Foundation (SOF) for students in classes 1 to 12, built to assess scientific reasoning and logical ability. It is aimed at school students enrolled in a school recognised by SOF, and each student sits the paper for their own class only. The exam is delivered offline in English and lasts one hour, with multiple-choice questions and problem-solving tasks; the syllabus spans topics such as metals and non-metals, carbon and its compounds, reproduction, electricity, magnetic effects, and control and coordination, alongside reasoning and a higher-order achievers component. Level 1 is open to classes 1 to 12, while level 2 is restricted to classes 3 to 12, with the class-wise top 5% of level 1 participants selected. Registration costs ₹170 and applications go through school authorities, not individual students, normally at least 30 days before the exam date. Preparation works best as a sequence: read the class-wise syllabus, work through the official sample model test papers, revise science fundamentals and reasoning, then practise previous-year papers under timed conditions. This page is an independent study resource and is not affiliated with SOF.
What you'll study
About SOF NSO preparation
What is the exam format and how long is it?
The SOF ISO is a pen-and-paper (offline) exam of one hour, delivered in English. Questions are multiple choice, with problem-solving tasks that test how well you apply science ideas rather than recall alone. The paper covers science topics from your class curriculum, logical reasoning, and an achievers section.
Who is eligible to appear?
Students from classes 1 to 12 enrolled in a school recognised by SOF are eligible for level 1, and you may appear only for your own class's paper. Level 2 is open to classes 3 to 12 only; there is no level 2 for classes 1 and 2. Class-wise top 5% of level 1 participants are selected for level 2.
How do I register and what does it cost?
Registration is ₹170, and applications must be submitted through your school authorities - students cannot apply individually. Forms should be submitted at least 30 days before the exam date, so check with your school office well before the deadline rather than waiting for an announcement.
When are the exams held?
For the 2026-27 session, level 1 is scheduled on 30 October 2026, 19 November 2026 and 3 December 2026. Your school decides which date applies to you, so confirm with your coordinator. These dates were announced ahead of time and may change, so verify against the official SOF schedule before planning.
Can I retake the exam if I do badly?
The exam is conducted once a year, and the source material does not describe any retake or re-attempt provision. Treat each sitting as your only attempt in that session and prepare accordingly. If you are unsure about your specific circumstances, ask your school coordinator to confirm with SOF directly.
How difficult is the paper?
Difficulty scales with class, and the achievers section raises the bar by asking higher-order application questions rather than straightforward definitions. Logical reasoning adds a second demand: speed and accuracy on non-science puzzles. Most students find the science portion manageable but lose marks on multi-step application and reasoning under time pressure.
What is the best study order?
Start with the class-wise syllabus to map exactly what is examinable, then revise your science fundamentals topic by topic. Move to the official sample model test papers to learn the pattern, then solve previous years' papers with a timer. Finish with targeted revision of weak topics and reasoning drills rather than new material.
What are the most common ways students lose marks?
Three patterns recur: ignoring the reasoning section because it is not science, misreading multi-step achievers questions and answering the first plausible option, and running out of time because practice was untimed. A fourth is skipping the syllabus and revising the whole textbook, which spreads effort too thin.
What awards are available?
Awards for 2026-27 include international, zonal and school topper recognition for classes 1 to 12. The top three international rank holders receive cash awards, medals and certificates, and schools, principals and teachers are also recognised. Exact amounts and criteria are published by SOF and should be checked there.