Science is a systematic way of observing, questioning, experimenting, and drawing conclusions about the natural world. It is not a fixed set of facts but a living, growing body of knowledge that keeps changing as we make new discoveries.
What is Science?
Science comes from the Latin word · scientia · , meaning knowledge. It involves observation, hypothesis, experimentation, and conclusion — together called the scientific method.
The Scientific Method
- 1.Observation – Noticing something in nature that sparks curiosity.
- 2.Question – Asking "why" or "how" about that observation.
- 3.Hypothesis – A testable guess or explanation.
- 4.Experiment – Designing a fair test to check the hypothesis.
- 5.Conclusion – Interpreting results and deciding if the hypothesis was correct.
Branches of Science
- Physics – Study of matter, energy, force, and motion.
- Chemistry – Study of substances, their properties, and reactions.
- Biology – Study of living organisms.
- Earth Science – Study of the Earth, atmosphere, and space.
Science and Technology
Science gives us understanding; technology applies that understanding to solve problems. The two constantly push each other forward. For example, understanding electricity (science) led to the invention of computers (technology).
Why Science Keeps Evolving
New instruments, better experiments, and fresh observations can overturn older ideas. For centuries people believed the Earth was the centre of the universe; observations by Copernicus and Galileo changed that understanding completely.
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A student notices that plants near a window grow towards the light. She hypothesises that plants grow towards light. She sets up two identical plants — one near a window and one in a dark cupboard — and observes them for a week. The plant near the window bends towards the glass; the cupboard plant wilts. Conclusion: Plants need and respond to light. This is the scientific method in action.
Ancient humans observed that rubbing two sticks together produced fire. This observation eventually led to the understanding of friction and heat, showing how everyday observations can drive scientific progress.
Early doctors believed illness was caused by "bad air." Careful experiments by Louis Pasteur showed that microorganisms cause disease — a complete revision of earlier thinking.
Scientists once thought atoms were indivisible. Experiments by J.J. Thomson (discovery of the electron) and Ernest Rutherford (discovery of the nucleus) showed the atom has internal structure, evolving our model of matter.
The discovery of penicillin by Alexander Fleming began with an accidental observation — mould on a petri dish was killing bacteria. This shows that careful observation, even of unexpected results, drives science forward.
Measuring temperature requires a thermometer. Science depends on accurate measurement. The SI system provides standard units so scientists worldwide can share and compare results reliably.
Climate scientists collect data over decades to identify patterns in global temperatures. This shows that science is a collaborative and long-term process, not just single experiments.
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Key Terms
- Hypothesis – A tentative explanation that can be tested.
- Variable – A factor that can change in an experiment.
- Fair test – An experiment where only one variable changes at a time.
- SI units – International System of Units (metre, kilogram, second, kelvin, etc.).
Common mistakes
- Confusing hypothesis with theory: a theory is a well-tested, widely accepted explanation backed by much evidence; a hypothesis is an initial, untested idea.
- Believing science gives absolute, unchangeable truth — science always remains open to revision with new evidence.
Summary
Science is a dynamic process of inquiry. Using the scientific method — observe, question, hypothesise, experiment, conclude — humans have built an ever-growing understanding of the universe. This knowledge is always open to revision, making science one of the most powerful tools available to humanity.