A scientific hypothesis is a provisional explanatory proposition, formulated to be tested through experimentation or observation. It constitutes the starting point of the scientific investigation process promoted by inquiry-based learning approaches (such as La main à la pâte) and school curricula.
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How to measure it in class
With FizziQ, students can formulate and then test hypotheses about physical phenomena.
Steps of the investigation process:
- Observe a phenomenon and formulate a question
- Propose explanatory hypotheses
- Design an experiment to test each hypothesis
- Carry out the experiment with FizziQ
- Analyze the results
- Conclude: is the hypothesis validated or refuted?
Example:
- Question: “Why does the pendulum oscillate more slowly when the string is longer?”
- Hypothesis: “The period depends on the length of the string”
- Test: Measure T for different lengths with FizziQ
- Analysis: Check whether T ∝ √L
Scientific activities on this topic
All FizziQ activities can be part of an investigation process with hypothesis formulation.
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Characteristics of a good hypothesis:
| Criterion | Description |
|---|---|
| Testable | An experiment can be designed to verify it |
| Falsifiable | A result that would contradict it can be imagined |
| Precise | It makes specific predictions |
| Consistent | It does not contradict known facts |
Hypothesis vs prediction:
- Hypothesis: “The period of the pendulum depends on the length”
- Prediction: “If I double the length, the period will be multiplied by √2 ≈ 1.4”
The scientific method cycle:
Observation → Question → Hypothesis → Experiment → Analysis → Conclusion → (new question)
Validation or refutation:
- A hypothesis is never “proven”, it is supported by experiments
- A single contradictory experiment can refute a hypothesis
- Science progresses by refuting false hypotheses
Formula
Structure of a hypothesis:
“If [condition/cause], then [observable consequence]”
Example: “If the period of the pendulum depends on the mass, then by doubling the mass, we should observe a change in period.”
(This hypothesis is refuted by experiment: the period does not depend on the mass!)
Application examples
- Hypothesis: “The speed of sound in air increases with temperature” → to be tested!
- Hypothesis: “The frequency of a tuning fork depends on temperature” → measurable with FizziQ
- Hypothesis: “The bounce height depends on the ball material” → testable
- Hypothesis: “The acceleration due to gravity is the same for all objects” → Galileo tested it
FAQ
Q: How can we help students formulate hypotheses? A: Start from their initial conceptions and ask “Why do you think that…?”. Transform their ideas into testable propositions.
Q: What should we do if the hypothesis is refuted? A: It is a valid scientific result! Refuting a hypothesis teaches as much as confirming it. It is an opportunity to formulate a new hypothesis.
Q: Can we test several hypotheses at once? A: It is tricky: only one parameter should be varied at a time in order to identify causes. Otherwise, you do not know which hypothesis is confirmed.
Q: Does FizziQ help validate hypotheses? A: Yes, by providing reproducible quantitative measurements that allow predictions to be compared with facts.
Related concepts
Experimental Protocol - Reproducibility