Rolling Ball Variables

Overview

Students investigate how forces and movement affect how far and how fast a ball rolls. They plan and conduct a repeatable “rolling ball” experiment by deciding which variables to change, measure, and control in a fair test, following a whole-class or group investigation approach.

Learning intentions

• Students will pose an investigable question about making a ball roll faster.
• Students will identify the independent (changed) variable, dependent (measured) variable, and controlled variables in a fair test.
• Students will use simple equipment to make repeatable measurements and record data with reasonable precision.
• Students will communicate findings using scientific language (e.g. gravity, force, friction, speed, distance).

Success criteria

• I can write an investigable question and make a reasoned prediction.
• I can run a fair test by changing only one variable and keeping others the same.
• I can measure and record results (e.g. time and/or distance) for repeated trials.
• I can explain which variable seemed to make the ball roll faster and why, using evidence.

Curriculum links

• Science Inquiry — Planning and conducting: VC2S6I02 (fair tests; deciding variables to change, measure and control).
• Science Inquiry — Questioning and predicting: VC2S6I01 (investigable questions and reasoned predictions guiding investigations).
• Science Inquiry — Planning and conducting: VC2S6I03 (using equipment to observe, generate, measure and record data with reasonable precision for repeated measurements).
• Science Inquiry — Communicating: VC2S6I06 (communicating findings for a purpose and audience with scientific vocabulary).
• Science Understanding (context): VC2S6U07 (cyclic and gravity ideas are part of Earth and space learning; in this lesson, gravity is used as the physical basis for the ball’s motion after prior teaching).

Lesson structure (60 minutes)

1. 0–5 min · Activate knowledge (gravity & forces). Teacher briefly reviews prior learning: gravity pulls objects down, and forces like friction affect motion; show the plank and ball setup. Students share one example of force affecting movement (e.g. skateboard slows due to friction).

2. 5–12 min · Hook: investigable question. Teacher asks: “How can we make a ball roll faster?” and demonstrates a quick roll for context. Students turn this into an investigable question using a “What happens if…?” structure and make a reasoned prediction (one variable they think will change speed).

3. 12–20 min · Direct teaching: fair test variables. Teacher guides students to choose variables they can actually manipulate with the materials (e.g. plank angle using books, start position, surface material, distance run, ball type/size only if class agrees it stays constant). Students complete a variables table for their chosen plan:

• Independent variable (what we change)
• Dependent variable (what we measure, e.g. time to travel a set distance)
• Controlled variables (what stays the same: plank length used, ball type/size, release position, surface, and how the ball is released)

4. 20–28 min · Model measurement & precision. Teacher demonstrates how to measure fairly: mark a start line, a finish line (e.g. 50 cm or a taped section), start the stopwatch at the same moment the ball is released, stop when it crosses the finish line, and repeat at least 3 trials. Students practise once with teacher support (1 trial each team member contributes to timing).

5. 28–45 min · Group experiment (whole-class or groups). Teacher sets up stations or whole-class shared trials using books/plank/ball/stopwatch/ruler. Students run their investigation, changing only the agreed independent variable and recording results in a simple table each trial includes: trial number, independent variable setting, measured time (or distance if that is the chosen dependent variable), and notes about any issues.

6. 45–54 min · Analyse quickly: which made it faster? Teacher prompts analysis: “Compare the averages. Which setting gave the shortest time (or greatest speed)?” Students calculate mean time from repeated trials and identify the trend (evidence-based claim), using sentence starters:

• “When we changed ___, the ball rolled faster because…”
• “The controlled variables were… so our results were fair.”

7. 54–60 min · Communicate & exit ticket. Teacher gathers two groups to share one result and one fair-test control they used. Students complete an exit ticket: (1) independent variable, (2) dependent variable, (3) one controlled variable, (4) one claim supported by data.

Resources

• Some books (for adjusting plank angle or setup height)
• A plank or straight solid surface
• Spherical object that can roll (same ball for each team if possible)
• Stopwatches (one per group or shared timer device)
• Ruler or tape measure (for marking distances)
• Marking tape/chalk for start and finish lines
• Worksheet or recording sheet with variables table and results table (Rolling Ball Experiment prompts)
• Timer screen/projector or teacher model for consistent stopping method
• Safety instructions reminder for clear floor space and controlled runs

Assessment

• Formative during variables planning: teacher checks each group’s variables match a fair test.
• Formative during trials: teacher observes measurement method consistency and repeat trials.
• Exit ticket: identifies variables correctly and uses measured results to support a claim.

Differentiation

• Support for planning: provide a partially filled variables chart and sentence starters for predictions and conclusions.
• Support for measurement: assign roles in each group (timer, measurer/marker, recorder, equipment checker) to reduce confusion.
• Challenge for early finishers: ask them to suggest how to improve precision (e.g. consistent release, more trials, smaller measurement intervals) and whether their results are reliable.
• EAL/SEN: allow oral rehearsal of the claim before writing; provide a word bank (gravity, force, friction, speed, time, distance, fair test).