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Session 4. Low-Cost Investigations, Groups and the 45-Minute Clock
Objective. Design a fair-test investigation with local materials and run it in 45 minutes with groups of four in a class of 30-40, with roles, stages and a plan for materials.
Many teachers say that inquiry is for schools with laboratories and small classes. In practice, bottles, soil, string, a watch and a clear routine are enough for real investigations, even with 40 students and a 45-minute bell. What makes it work is not equipment but preparation: a fair-test plan, groups with roles and a timetable you can keep. This session shows you how to build all three from what you already have around the school.
Key ideas
Materials from around the school
- Good investigations do not need a laboratory. Plastic bottles, cups, soil from the yard, stones, seeds, string, rulers, a watch, water from the tap and from the canal, sunlight and shade are enough for dozens of questions.
- The UNESCO Source Book for Science Teaching shows how simple equipment from the local area can carry real science. Students can also collect, count and compare, which works in language, mathematics and geography.
- Safety first: no open flame or glass for students, no tasting, no unknown chemicals, hot water only handled by the teacher. State these rules before materials are handed out.
A fair test in five lines
- Write five lines on the planning sheet: 1) Question. 2) We change (one thing). 3) We measure (one thing, with a unit). 4) We keep the same (at least three things). 5) We repeat (at least three times).
- Example: 'Which soil from our yard holds water best?' Change: soil type. Measure: ml of water collected after 2 minutes. Keep the same: 100 g of soil, 100 ml of water, same cup.
- Not every question is a fair test. A survey (what proverbs do grandparents know?) or a classification (which seeds are cotton?) is also inquiry; use the five lines only when something is changed.
Fitting inquiry into 45 minutes and 40 students
- A workable shape: Launch 5, Plan 5, Investigate 18, Share 12, Exit ticket 5. Prepare materials in advance in one tray per group, so that no minutes are lost handing out cups.
- Groups of four with fixed roles: materials manager, recorder, timekeeper, reporter. For 40 students that is 10 groups; if materials are short, run two or three stations and rotate, or give the same question to pairs of groups.
- Share with a gallery walk: each group posts one sheet; students walk for 6 minutes with two sticky notes (one 'I noticed', one 'I wonder'). If the investigation needs more time, plan two lessons and stop the first at the data.
Try it in your next lessons
- Run one fair-test investigation with a timed plan on the board. Write the minute marks (0, 5, 10, 28, 40, 45) and tick them as you go.
- Evidence to bring back: a photo or copy of two group sheets (one strong, one weak) and one line on where the clock slipped.
- Ask students: 'What would you change if you did it again?' and write three answers.
A 45-minute inquiry (minutes are a model)
Fair tests: change one thing
The most common weakness in student investigations is changing two things at once. A group that compares two soils but pours more water on one cannot say which soil did the work. The five-line sheet fixes this by forcing the group to write what it changes, what it measures with a unit, what it keeps the same and how many times it repeats.
Local materials make repeating cheap. Three cups of soil cost nothing, and three repeats show students that results vary and that one measurement is not a fact. Remember that not every question is a fair test; surveys and classifications are inquiry too.
Time and large classes
In 45 minutes, the investigation itself may be only 18 minutes. Everything else must be quick: trays prepared before the bell, roles written on the board, a visible clock, and a rule that the timekeeper announces minute 20 and 25. Rehearse the routine once with a simple task, then use it with every investigation.
A larger class is mainly a matter of structure. Groups of four with fixed roles keep everyone busy; two or three stations let you share a few scarce items; a gallery walk lets 10 groups report without 10 presentations. The Education Endowment Foundation toolkit rates reduced class size as low impact for very high cost, so your routines are the practical lever.
Examples from the classroom
Soil and water in Karshi
Scene. Malika, Grade 6, Karshi, has nine cups with small holes, three soils from the yard, cloth and one measuring cup per group. Groups write the five lines, pour 100 ml of water through 100 g of soil, and measure the water in the cup after two minutes. They repeat three times. The class table shows sandy soil drains most, and groups argue about why.
Insight. A fair test with free materials gives data a whole class can compare.
Forty students, six magnifiers
Scene. Dilnoza teaches 40 Grade 6 students in Tashkent and owns six magnifiers. She makes ten groups of four and three stations: seed table with magnifiers, measuring table and recording table. Groups rotate every six minutes. Roles stay the same within a group, so each group has a timekeeper who moves the group on.
Insight. Stations let a few scarce items serve a large class without lost minutes.
A survey in Andijan
Scene. Aziz teaches Grade 5 Uzbek in Andijan and has no materials at all. His question is 'Which proverbs about work do grandparents in our street know?'. Each student asks two relatives, writes the proverbs on slips, and groups sort them by theme the next day. It costs nothing, takes two lessons and produces a classroom wall of data.
Insight. Inquiry needs a real question and real evidence, not equipment.
Common pitfalls
- Handing out materials during lesson time, which can use 8 of the 45 minutes.
- Letting groups choose their own roles each lesson, so the same student always writes and the same one never does.
- Forgetting safety rules for hot water, glass and tasting before the materials are on the desks.
- Skipping the sharing stage when time runs short; then students never hear what the data meant.
Plan a 45-Minute Inquiry with Local Materials
- Choose one question from the list in your Activity Kit (or your own from Session 2). Alone (5 min): list the local materials you would need, and the cost in som or 'free'.
- In pairs (15 min): fill the five-line fair-test sheet. Check: only ONE thing changes, the measurement has a unit, at least three things are kept the same, and there are three repeats.
- In groups of four (15 min): build the 45-minute timetable on the Timing Grid for 36 students: stages with minutes, 9 groups, four roles, where materials sit, and what you cut if you are 5 minutes late.
- As a whole group (15 min): two groups present their timetable in 3 minutes each; others ask 'where does the plan break?'. Write one fix on your own sheet.
- Homework: gather the materials for your investigation from home or school, and test it once yourself.
Your facilitator will guide you through this activity in the session.
Questions to discuss
- Which step of the timetable took longer than you expected, and what would you prepare in advance?
- What could go wrong with safety or with materials, and what is your plan?
- How will you make sure every student in a group of four has a real task?
Reflect
- What materials do you already have in your classroom that you never use for investigations?
- In a class of 40, which role is hardest to give to a shy student, and how will you help?
- What will you cut first if the lesson runs 5 minutes late?
Try it tomorrow
- Write the minute marks (0, 5, 10, 28, 40, 45) on the board and tick them as the lesson goes.
- Prepare one tray per group before the bell and name the four roles on the board.
- Keep two group sheets (one strong, one weak) and note the minute where your timetable slipped.
Further reading and links
Use local materials, a five-line fair test, groups with roles and a timed plan; prepare trays before the bell.