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Science Olympiad · Bay Area ESO 2027

Bay Area Elementary Science Olympiad 2027.

The 20th annual Bay Area ESO, run by Science Gurus, a parent-run nonprofit in Fremont. Grades 3–6, teams of 4 to 8 students, eleven events across an online Friday evening and an in-person Saturday. Team registration for 2026–27 has closed — the organizers reached capacity ahead of their November 30, 2026 deadline. We're not affiliated; our prep for it is live for all eleven events.

Grades
3 – 6
Events
11
Team size
4 – 8
Registration
Closed (at capacity)
§01 / Dates and registration

Two days. One team of eight.

What the organizers have published for 2027.

  • Friday, March 26, 20276:00 – 8:30 pm · online theory events via Zoom and Google Forms
  • Saturday, March 27, 20277:30 am – 5:00 pm · in-person events and awards at Thornton Middle School, 4357 Thornton Ave, Fremont, CA 94536
  • RegistrationHead coaches register teams at sciencegurus.org. $360 per team. Eligibility: 3rd – 6th grade students from the Bay Area. Deadline November 30, 2026, or earlier if capacity is reached.

The organizers note that rules may change until November 30. The event details document is the source of truth.

§02 / The eleven events

What each event is, in one line.

Names and formats are the organizers'. Full rules and sample questions are in their public folders: Rules · Sample questions.

  • Anatomy and PhysiologyOnline theory · Friday (online)Integumentary, skeletal, and muscular systems.Prep space — live
  • CodebustersIn-person, analytical · SaturdayBaconian, Porta, Aristocrat, Cryptarithm, Caesar, Atbash.Prep space — live
  • Crime BustersIn-person lab · SaturdayFingerprints, hair and fiber, soil, powders and liquids.Prep space — live
  • EcologyOnline theory · Friday (online)Ecology and adaptations in North American biomes.Prep space — live
  • Engineering CADOnline, engineering design · OnlineParts and an assembly in Onshape, from engineering drawings.Study guide — live
  • EntomologyOnline theory · Friday (online)Identify insects by order, subclass, or family; dichotomous keys.Prep space — live
  • HovercraftIn-person build · SaturdayA self-propelled air-levitated vehicle run to a target time.Study guide — live
  • PentathlonIn-person relay · SaturdayWhole team. Math, ecology, solar system, cell biology, geology.Practice sets — live
  • Rubber Band CatapultIn-person build · SaturdayA catapult that shoots a rubber band at a ringed target.Study guide — live
  • Science JeopardyRound 1 online · Round 2 in person · Friday + SaturdayA 30-question first round across 15 science topics; top four teams play the finals.Practice sets — live
  • Water QualityOnline theory · OnlineFreshwater ecology, macroinvertebrates, water monitoring.Prep space — live
§03 / Every event, in depth

What each event asks, and what we have for it.

Eleven events, one block each. The scope is paraphrased from the organizers' 2027 rules — read those before you decide anything. Where a number on this page is OlyPrep's reading of the rules rather than something the organizers publish, the line says so.

Anatomy and Physiology

Human Body & Anatomy · Online theory · Friday (online)

An online multiple-choice test on the Friday evening, taken on a Google Form by two teammates working together — thirty minutes, one question on screen at a time, and no going back to one you have passed.

  • SkinWhat it does and how it is built: the layers and their histology, hair, nails and the two kinds of sweat gland, sensory receptors, and the effects of aging. Then the conditions on the organizers’ list — burns and their classes, sunburn, the named infections, psoriasis and dermatitis, and the skin cancers — with treatment and prevention.
  • Bones and jointsThe axial and appendicular skeleton, and labelling a bone’s surface anatomy on a diagram, an X-ray, a CT or an MRI. Joint types, what attaches around them, and the range of motion each allows.
  • How bone worksOsteons, marrow and cartilage; the skeleton’s part in calcium and phosphate balance; the hormones that act on bone. The listed disorders — osteoarthritis against rheumatoid arthritis, gout, osteoporosis, scoliosis and the rest — and fractures, including the Salter-Harris classification.
  • MuscleSkeletal, cardiac and smooth muscle, gross and cellular. How tension is produced: sarcomere length-tension, motor units, the neuromuscular junction and cross-bridge cycling. Agonist, antagonist and synergist pairs, and the origin, insertion and function of every muscle on the 2027 Major Skeletal Muscles List.

What OlyPrep has for it

  • 01A prep space scoped to these rules — practice questions in the format the event uses, an AI coach that answers only inside this event, and study notes.
  • 02Test day: thirty questions in thirty minutes, one a minute, no going back. The thirty minutes is the rules’ own figure; the question count is OlyPrep’s reading of the rules, not a number the organizers publish.
  • 03At least four questions on a Test day paper show a labelled anatomy render. That quota is OlyPrep’s — the organizers have not said how many.
  • 04Short audio lessons read from these rules — one for each part of the syllabus above. Free on every plan, and they spend no credit.
  • 05Rows on My report card for each part of the event, with the kid’s own papers listed oldest to newest. Free on every plan.

Codebusters

Codes & Ciphers · In-person, analytical · Saturday

A written paper in person on the Saturday — twenty questions in forty minutes for two teammates, with the organizers’ reference sheet on the desk. Ten to fifteen are free-response decodes; the rest are multiple-choice or fill-in.

  • Six ciphers, at the rules’ own point valuesAtbash (10–20), Baconian (20–40), Caesar (30–40), Porta (50–70), Cryptarithm (70–90) and Aristocrat (80–100). Harder ciphers are worth more, so which ones a kid can do decides the score.
  • Cracking without a keyLetter-frequency analysis and pattern words, for an aristocrat that arrives with no hint at all.
  • The timed opening questionAn unhinted aristocrat, first on the paper. The bonus is six hundred minus the seconds taken, divided by five, and the window is open for the first ten minutes.
  • The mechanicsBaconian’s five-symbol A/B patterns on the 24-letter alphabet that merges I with J and U with V; Porta’s reciprocal keyword alphabets; recovering which digit each letter stands for in a cryptarithm.

What OlyPrep has for it

  • 01A prep space scoped to these rules, plus the Cipher Lab — unlimited on every plan, Free accounts included. A subtopic button opens the Lab already set to that cipher.
  • 02Test day: the whole paper for the full forty minutes, in any order, scored in points per cipher with the timed bonus on the first question. Both numbers are the rules’ own. The paper is composed fresh by the cipher engine each time, so it is never the same twice.
  • 03Short audio lessons read from these rules — one for each part of the syllabus above. Free on every plan, and they spend no credit.
  • 04My report card scores Codebusters cipher by cipher, so a kid can see that Porta is the one costing them points.

Crime Busters

Forensics · In-person lab · Saturday

An in-person lab on the Saturday: a crime-scene story, physical evidence and a set of suspects. Two teammates test the evidence, answer questions on the story and the theory behind it, and write a paragraph naming who did it. Forty-five minutes.

  • FingerprintsComparing a scene print with a suspect’s, reading minutiae, and the pattern families — loops (ulnar, radial, central pocket), whorls (plain, accidental, double loop) and arches (plain, tented).
  • Hair and fibreUnder the microscope: human hair against dog, cat, squirrel and mouse; animal, vegetable and synthetic fibres, down to telling cotton, linen, silk, nylon, rayon and polyester apart.
  • Powders and liquidsIdentifying every powder on the list with nothing but iodine, hydrochloric acid and distilled water, and every liquid by pH with your own strips — their uses and their chemical formulas, and how a mixture of powders behaves with each reagent.
  • SoilsTelling peaty, loamy, sandy, clay, chalky and silty samples apart.
  • The write-upName the suspect and their motive, then take each piece of evidence in turn and say why it points at them.
  • Lab safetyGoggles, a coat or apron, skin covered and hair tied back whenever the acid is out — and the five per cent the rules take off for missing gear, prohibited equipment or a bad cleanup.

What OlyPrep has for it

  • 01A prep space scoped to these rules — practice questions, an AI coach held inside this event, and study notes.
  • 02Test day: twenty questions in forty-five minutes, the whole paper in any order, marked by the rules’ own section weights — fingerprints 20, hair and fibre 15, soil 20, chemical 25, and the written analysis 20, out of a hundred. The written analysis is marked against a rubric, not by keyword.
  • 03The forty-five minutes and the section weights are the rules’. The question count is OlyPrep’s — the organizers publish the weights and not a count.
  • 04At least three questions carry a real fingerprint, hair or fibre photograph. That quota is OlyPrep’s.
  • 05Short audio lessons read from these rules — one for each part of the syllabus above. Free on every plan, and they spend no credit.
  • 06Rows on My report card for each part of the event, with the kid’s own papers listed oldest to newest. Free on every plan.

Ecology

Ecology & Environment · Online theory · Friday (online)

An online test on the Friday evening — thirty questions in thirty minutes for two teammates, one question on screen at a time. The organizers put weight on process skills, so expect graphs and tables rather than recall alone.

  • How an ecosystem is put togetherIndividual to population to community to ecosystem to biome to biosphere; energy and nutrient transfer, the ten per cent rule, pyramids of number, biomass and energy, and the biogeochemical cycles.
  • PopulationsCarrying capacity, overshoot and dieback; density-dependent against density-independent limiting factors; dispersion patterns, life tables and survivorship curves; r- and K-selected life histories; logistic and exponential growth.
  • Change over timePrimary and secondary succession and climax communities; natural selection in its four forms; speciation, adaptive radiation, convergent and divergent evolution, genetic drift and mass extinctions.
  • Biomes and climateThe Coriolis effect and rain shadows and how they place the major terrestrial biomes — with deserts and grasslands in depth, including the adaptations of the plants and animals that live there.
  • What people do to itClimate change and ocean acidification, habitat destruction and fragmentation, invasive species and the four ways of controlling them, bioaccumulation and biomagnification, eutrophication, erosion and desertification; the alternative energy sources and the trade-off each one carries; conservation biology and the IUCN Red List.
  • Reading the dataDefining variables, analysing a graph or a table, forming a hypothesis and making a prediction.

What OlyPrep has for it

  • 01A prep space scoped to these rules — the outline runs all six energies and every major biome, not another tournament’s syllabus.
  • 02Test day: thirty questions in thirty minutes, one a minute, no going back. Both numbers are stated in the rules.
  • 03At least four questions show a chart or a table drawn from real data, because that is how the event asks them. That quota is OlyPrep’s.
  • 04Short audio lessons read from these rules — one for each part of the syllabus above. Free on every plan, and they spend no credit.
  • 05Rows on My report card for each part of the event, with the kid’s own papers listed oldest to newest. Free on every plan.

Engineering CAD

Engineering & CAD · Online, engineering design · Online

An online practical. Two students model parts and an assembly in Onshape from engineering drawings handed out on the day, then submit a public link through a Google Form. Thirty minutes, scored on surface-area accuracy against the answer key and on correct assembly mates, with modelling time as the tiebreaker.

  • Reading the drawingFront, top and right orthographic views, isometric views, detail zoom circles, drawing format, and the abbreviations — THRU, TYP, R.
  • Sketching to a constraintFully constrained 2D sketches: circles and ellipses, inscribed and circumscribed polygons, splines; projections, fillet and chamfer, trim and extend, offset, mirror, transform and patterns — with the dimensions and the coincident, concentric, tangent, equal and symmetric constraints that lock them.
  • Making solidsExtrude and revolve with blind, symmetric, up-to-face and up-to-next end conditions; loft between profiles; holes of each kind, 3D fillets and chamfers, reference planes and patterns.
  • AssembliesInserting and fixing a base part, placing mate connectors on circles, vertices and midpoints, and knowing what a fasten, revolute or slider mate removes.
  • How it is scoredAccuracy as your surface area over the key’s, the assembly starting at a hundred and losing five per incorrect mate, and the clock as the tiebreaker.

What OlyPrep has for it

  • 01A rules-derived study guide, and an AI coach in learning mode. Included with every Bay Area ESO account, free and Premium alike, and it uses no topic slot.
  • 02No Test day paper: there is no test to sit.
  • 03The scoring math, and the five practice models the organizers name, are in §04 below.

Entomology

Insects & Entomology · Online theory · Friday (online)

An online test in the first Friday block — thirty questions in thirty minutes for two teammates. Specimens come from the organizers’ 2027 list of insects found in the contiguous United States, and arrive as images.

  • IdentificationNaming the listed taxa from a photograph by order, subclass, family or common name, using the features the image actually shows — and both using and building a simple dichotomous key.
  • AnatomyHead, thorax and abdomen inside and out, mouthparts, legs and wings, and how each differs across the listed orders.
  • EcologyHabitat, adaptation and behaviour for each listed group; symbiosis and competition; relationships with plants, animals and public health; and what a changing climate does to them.
  • Why they matterInsects as a source of food, medicine, disease, chemicals and nutrients — and as nuisance species.
  • SystematicsThe class, order and family hierarchy of everything on the list, including the one animal on it that is not an insect: hard-backed ticks.
  • The water groupsMayflies, dragonflies and damselflies, stoneflies, dobsonflies, caddisflies, water beetles and bugs, mosquitoes and crane flies.

What OlyPrep has for it

  • 01A prep space scoped to these rules, with identification decks built from the organizers’ own 2027 list.
  • 02Test day: thirty questions in thirty minutes, one a minute, no going back. The thirty minutes is stated in the rules; the question count is OlyPrep’s reading of them.
  • 03At least twelve questions on a Test day paper carry a licensed photograph to identify, because an entomology paper without pictures is not the event. That quota is OlyPrep’s.
  • 04Short audio lessons read from these rules — one for each part of the syllabus above. Free on every plan, and they spend no credit.
  • 05Rows on My report card for each part of the event, with the kid’s own papers listed oldest to newest. Free on every plan.

Hovercraft

Hovercraft Engineering · In-person build · Saturday

A build event on the Saturday. Two students design, build and calibrate a self-propelled, air-levitated vehicle, impound it in the morning, and then run it down a straight track to finish as close as possible to a target time assigned at the start of prep — six, nine, twelve or fifteen seconds. Up to three official runs inside a twelve-minute slot, and no practice runs.

  • What you are allowed to buildThe size box, the levitation height, guarded fans, which batteries count as legal and which do not, a switch per motor — and which electrical parts the rules admit at all.
  • The track and the timing dowelThe dowel’s minimum thickness and maximum height, where it stands so it crosses the timing line first, and the track’s loading zone, timed section and clearance.
  • CalibrationHow battery voltage and added weight change a run, and keeping a settings table that turns an assigned target time into a lookup rather than a guess.
  • The design log and the scoring mathThe log in the order the rules require, and the formulas behind distance, time, the bonus run and the penalties.

What OlyPrep has for it

  • 01A rules-derived study guide, and an AI coach in learning mode. Included with every Bay Area ESO account, free and Premium alike, and it uses no topic slot.
  • 02No Test day paper: there is no test to sit.
  • 03The construction limits, the log order and the worked scoring math are in §04 below.

Pentathlon

Science Pentathlon · In-person relay · Saturday

A relay for the whole team on the Saturday — up to eight students, five rounds. Each round is a physical activity to reach the quiz table, a short set of multiple-choice questions on paper, and the same activity back. Theory is half the score and total time is the other half, and the two ranks are averaged.

  • MathArithmetic through basic algebra — the rules put the ceiling there and no higher.
  • EcologyFood chains and webs, habitats and biomes, and ecological footprint.
  • Solar systemConstellations, stars, planets, moon phases, the sun and eclipses.
  • Cell biologyCell structure, and mitosis and meiosis in their simplified form.
  • GeologyPlate tectonics, rock types, the rock cycle and the layers of the earth.
  • The relay itselfPairs work each round; an activity done wrong means starting that round again; the next pair goes on a high-five. One point per correct answer, nothing lost for a wrong one.

What OlyPrep has for it

  • 01Timed practice sets across all five relay topics, at the breadth the quiz table actually asks for.
  • 02No Test day paper for this one. Half the score is how fast the team moves, and that half cannot be practised on a screen — so OlyPrep covers the theory half and says plainly that it is the half it covers.
  • 03Short audio lessons read from these rules — one for each part of the syllabus above. Free on every plan, and they spend no credit.
  • 04Rows on My report card for each part of the event, with the kid’s own papers listed oldest to newest. Free on every plan.

Rubber Band Catapult

Catapult Engineering · In-person build · Saturday

A build event on the Saturday. Two students build a catapult that shoots a rubber band at a ten-ring target, then take three shots with three different bands at one distance assigned on the day, somewhere between four and ten metres. Twenty minutes.

  • What you are allowed to buildThe size box the catapult must fit in at every configuration and launch angle, and the band rules — a maximum free-hanging length, never knotted, linked or attached to anything else.
  • What happens when a band fails inspectionThe judges substitute bands and the team does not get to choose, which is the argument for bringing compliant spares.
  • TuningBase position and arm pull-back angle against distance travelled, measured and written down — because the assigned distance is not known until the day.
  • The design log and the data tableThe log in the rules’ order, and the test-shot table that is the last tiebreaker the rules reach for.
  • ScoringTwenty points for the smallest ring and one less for each ring out, an X for touching the centre dot, and the tiebreak order that follows.

What OlyPrep has for it

  • 01A rules-derived study guide, and an AI coach in learning mode. Included with every Bay Area ESO account, free and Premium alike, and it uses no topic slot.
  • 02No Test day paper: there is no test to sit.
  • 03The construction limits, the log order and the worked scoring math are in §04 below.

Science Jeopardy

Science Jeopardy · Round 1 online · Round 2 in person · Friday + Saturday

Two rounds. An online thirty-question test on the Friday evening across fifteen science topics, then a Jeopardy-style final on the Saturday for the top four teams, where answers are given as questions.

  • Fifteen topics, named by the organizersMatter and elements · the nervous system · rocks and minerals · Newton’s three laws · famous scientists · cellular biology · ecology · animal classification · energy and waves · units of measurement · genetics · dinosaurs · climate change · simple machines · the sun.
  • Breadth over depthThirty questions across fifteen topics means about two apiece. The first round rewards a team that has covered everything rather than one that has gone deep on a favourite.
  • The finals formatPick a category and a value from 100 to 500, then thirty seconds to answer in the form of a question. A wrong or late answer subtracts the value. Double Jeopardy doubles the values as a free-for-all, and Final Jeopardy is a single wagered question.

What OlyPrep has for it

  • 01Timed practice sets at the first round’s own breadth — all fifteen topics, not a subset.
  • 02Test day: thirty questions in thirty minutes, one a minute, no going back. Both numbers are stated in the rules.
  • 03The finals board, built the way the event runs it: five categories, five values, thirty seconds a clue, a wrong or late answer subtracting its value, and answers phrased as questions. Clues come from OlyPrep’s own validated bank and the whole board is marked on the server.
  • 04Short audio lessons read from these rules — one for each part of the syllabus above. Free on every plan, and they spend no credit.
  • 05Rows on My report card for each part of the event, with the kid’s own papers listed oldest to newest. Free on every plan.

Water Quality

Water Quality · Online theory · Online

An online test in the first Friday block — thirty questions in thirty minutes for two teammates. Charts, graphs and sample data are part of it, not a garnish.

  • Freshwater scienceAquatic ecology and the water cycle, nutrient cycling, the chemistry of the water and what it means for the things living in it, and sedimentation pollution.
  • The macroinvertebrates on the listIdentifying the adults by common name, and knowing their general ecology and how they feed.
  • Reading them as indicatorsThe five pollution classes — sensitive, moderately sensitive, moderately tolerant, tolerant, and air-breathing — and which listed organism belongs in each.
  • MonitoringSalinity, pH, phosphates, turbidity, dissolved oxygen, temperature, nitrates and biochemical oxygen demand: why each is measured, how, and how they move against one another — what a rise in temperature says about the oxygen, for instance.
  • TreatmentPotable-water and wastewater treatment, step by step, and what each step is for.
  • The restThe aquatic nuisance plants and animals on the list and why each is a problem; aquatic food webs, community interactions and population dynamics; and reading charts, graphs and sample data.

What OlyPrep has for it

  • 01A prep space scoped to these rules — the listed macroinvertebrates, their five pollution classes, and all eight monitoring parameters.
  • 02Test day: thirty questions in thirty minutes, one a minute, no going back. Both numbers are stated in the rules.
  • 03At least four questions show a chart or a table drawn from real monitoring data. That quota is OlyPrep’s.
  • 04Short audio lessons read from these rules — one for each part of the syllabus above. Free on every plan, and they spend no credit.
  • 05Rows on My report card for each part of the event, with the kid’s own papers listed oldest to newest. Free on every plan.

Scope is paraphrased from the organizers' published 2027 rules and event details, and the organizers note that rules may change until registration closes. Their documents are the source of truth: Rules · Sample questions · Event details. We are not affiliated with Science Gurus.

§04 / The build events, in brief

Judged on what you build, not on a test.

Hovercraft, Rubber Band Catapult, and Engineering CAD have no practice test to generate — so OlyPrep carries study guides for them: construction limits, the design-log order, and the scoring math with worked examples. The short version is below; the full guides sit in the prep workspace next to your kid's topics — included with every Bay Area ESO account, free and Premium alike, without using a topic slot, because there's no AI to meter on a build event. Source: the organizers' 2027 rules.

Hovercraft

Design and build a self-propelled, air-levitated vehicle, then run it down an 8-foot track to finish as close as possible to an assigned target time — 6, 9, 12, or 15 seconds, drawn at random. Up to three official runs in a 12-minute slot, no practice runs, device impounded beforehand.

  • 01Fits a 40 × 40 × 40 cm box · levitates about 2.5 cm · guarded fans · commercial batteries to 12 V, detachable — no lithium or lead-acid
  • 02Scoring: distance (30 max) + closeness to the target time (60 max); best run counts, with bonus-run and time-incentive paths for accurate teams
  • 03A design log in the rules’ required order, ending in a settings table — tested voltage and weight per target time

Organizer build videos ↗

Rubber Band Catapult

Build a catapult that shoots a rubber band at a ten-ring target placed 4–10 meters away. Three shots with three different bands, all at one distance assigned on the day. The smallest ring scores 20, each larger ring one less; touching the 2 cm center dot adds an X — the first tiebreaker.

  • 01Fits a 3 × 3 × 3 ft box in every configuration and launch angle · bands at most 22 cm hanging freely, never knotted or linked
  • 02The rules’ last tiebreaker is the best-prepared data table: base position, arm angle, and measured distance for every test shot
  • 03The habit that wins: organize the data table by distance, so the assigned range is a lookup, not a guess

Engineering CAD

A live 30-minute Onshape practical: model parts and an assembly from engineering drawings handed out at competition time, then submit a public link. Scored on surface-area accuracy against the answer key and on correct assembly mates; the tiebreaker is modeling time.

  • 01Scope: fully constrained sketches, extrude/revolve/loft, holes and fillets, reference planes and patterns, and fasten/revolute/slider mates
  • 02Reading drawings is half the event: orthographic views, detail circles, and abbreviations like THRU, TYP, and R
  • 03The organizers name five practice models — Rook, Key, Fidget Spinner, Bishop, Trophy — worth modeling against the clock

Onshape free education plan ↗

§05 / Live today

Prep scoped to these rules, not someone else's.

Live today, all eleven: prep spaces for Anatomy and Physiology, Codebusters, Crime Busters, Ecology, Entomology, and Water Quality — scoped to the 2027 rules — plus timed practice sets for Pentathlon and Science Jeopardy, and study guides for the three build events.

Each prep space is built from the organizers' 2027 rules: practice questions in the format the event uses, an AI coach that only answers inside that event's scope, audio lessons for the car, and a cipher practice lab for Codebusters. The anatomy syllabus is skin, bones, and muscles; the ciphers are the six on the organizers' list; the insect ID decks cover the organizers' 2027 Entomology list; the ecology outline runs all six energies and every major biome; the water-quality space covers the listed macroinvertebrates, their five pollution classes, and the eight monitoring parameters — nothing borrowed from another tournament's year.

The two timed drills cover what the clock actually asks of them: Pentathlon's five relay topics, and Science Jeopardy's fifteen listed topics at the thirty-question breadth of its online first round. Pick Bay Area ESO at signup and your kid's workspace carries the whole slate.

Beyond practice, each of the seven theory events has a Test day: the event's real paper on the organizers' clock, one submit, marked the way the rules mark it. Science Jeopardy has its second-round board, thirty seconds a clue with a wrong answer subtracting its value. Every kid gets My report card, which breaks each event down by the specific things it tests and says what to practise next, and an episode library of short audio lessons read from these rules — one for each thing an event asks your kid to know. The report card and the episodes are free on every plan.

Free for two topics — no credit card. The three build-event guides come on top of your topic picks, at no cost, on every account.