🧪 What Is a Hypothesis?
✅ Definition:
A hypothesis is an educated guess or testable explanation for a scientific problem or observation.
It answers the question:
“What do I think is happening, and why?”
It must be:
-
Testable (you can design an experiment to check it)
-
Falsifiable (it can be proven wrong)
-
Based on prior knowledge or observation
📘 Example:
If plants receive more sunlight, then they will grow faster.
🠖 This is a hypothesis because it predicts something measurable and testable.
📜 Origin of the Word “Hypothesis”
-
Comes from Greek:
-
“hypo” = under
-
“thesis” = placing or proposition
-
So hypothesis originally meant: “a proposed idea placed under investigation”
-
-
First used in Greek philosophy by Plato and Aristotle when discussing logic and reasoning.
📚 Historical Development
🏛️ Ancient Greece:
-
Aristotle (384–322 BCE):
Talked about using observation and reasoning, but he did not use experiments the way modern science does. -
Euclid (geometry): Used hypotheses as starting points (axioms) for logical conclusions.
⚗️ Scientific Revolution (1500–1700s):
-
Francis Bacon: Promoted the idea of inductive reasoning (start with observations to form general hypotheses).
-
Galileo and Newton: Used hypotheses in forming laws of motion and gravity — but also emphasized testing with experiments.
🧪 Modern Science (1800–present):
-
Karl Popper (20th century):
Said a good hypothesis must be falsifiable — it must be able to be tested and potentially disproven.
🔬 Hypothesis in the Scientific Method
-
Observation: Notice something in the world.
-
Question: Ask “Why or how is this happening?”
-
Hypothesis: Make a guess based on what you know.
-
Experiment: Test your guess with data.
-
Analysis: See if results support or reject your hypothesis.
-
Conclusion: Decide if you were right — or make a new hypothesis.
🔁 Important:
A hypothesis is not the final answer — it is a starting point in science.
🧠 Types of Hypotheses
| Type | Description | Example |
|---|---|---|
| Null Hypothesis (H₀) | No effect or relationship | "There is no difference in plant growth with or without sunlight." |
| Alternative Hypothesis (H₁) | There is an effect or relationship | "Plants grow faster with more sunlight." |
| Directional Hypothesis | Predicts the direction of the effect | "If temperature increases, bacteria grow faster." |
| Non-directional Hypothesis | Predicts a difference, not its direction | "There is a difference in growth between A and B." |
🎓 Why Hypotheses Matter in Science
-
They help focus research.
-
They allow scientists to make predictions.
-
They make science systematic and logical.
-
They are the foundation of experiments.
📌 Summary
| Feature | Explanation |
|---|---|
| Meaning | A testable explanation or prediction |
| Origin | Greek word meaning “under-proposition” |
| Used in | Scientific Method |
| Must be | Testable and falsifiable |
| Evolved by | Plato → Aristotle → Bacon → Newton → Popper |