What Is a Scientific Law?
✅ Definition:
A scientific law is a statement that describes a consistent, universal pattern in nature based on repeated experiments and observations.
📌 It tells what happens under certain conditions — always, without exceptions.
Unlike a theory (which explains why or how), a law describes what always happens when conditions are the same.
🧠 Characteristics of a Scientific Law:
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Based on evidence from repeated experiments
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Predictable and universal
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Often expressed with formulas or math
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Not changed, unless new evidence completely disproves it (very rare)
📘 Examples of Scientific Laws:
| Law | Description |
|---|---|
| Newton’s First Law of Motion | An object stays at rest or moves at a constant speed unless acted upon by a force. |
| Law of Gravity | All objects attract each other with a force called gravity. |
| Law of Conservation of Mass | Mass is not created or destroyed in a chemical reaction. |
| Ohm’s Law | The relationship between voltage, current, and resistance in a circuit (V = IR). |
| Boyle’s Law | For gases, pressure and volume are inversely related at constant temperature. |
📜 Origin of the Word “Law”
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From Latin: “lex” meaning “rule” or “standard”
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In science, a law is not a rule created by humans, but a natural rule observed in the universe.
🔬 Law vs. Theory vs. Hypothesis
| Term | What it means | Can it change? | What it does |
|---|---|---|---|
| Hypothesis | A testable idea or guess | Yes – tested by experiments | Suggests a possible explanation |
| Theory | A well-tested explanation | Can be updated or refined | Explains how or why something happens |
| Law | A statement of consistent observation | Rarely changes | Describes what always happens |
🧩 Example:
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Law: Objects fall to the ground due to gravity (what happens).
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Theory: Einstein’s Theory of General Relativity explains why gravity happens.
🎓 Importance of Scientific Laws
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Help predict outcomes in experiments
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Support technological innovation
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Give scientists a common framework to describe natural behavior
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Often form the foundation for further theories and research
📌 Summary
| Feature | Scientific Law |
|---|---|
| Definition | Describes a universal pattern in nature |
| Based on | Repeated observations and experiments |
| Explains? | No — it describes, not explains |
| Reliable? | Very — rarely disproven |
| Examples | Gravity, motion, conservation laws |