1) The language of science needs to be precise, with terms clearly defined, and may involve mathematical language. 2) Observations can be made directly through senses or indirectly through instruments, which can provide more reliable data, acting as extensions of our senses. Quantitative data is preferred. 3) A hypothesis is an educated guess used to explain a phenomenon and make predictions to enable experimentation. Experiments are designed to test hypotheses by controlling variables, and hypotheses accumulate evidence or are modified or discarded based on results.

1. BASIC CONCEPTS OF
SCIENCE

2.  The language that describes science needs to be precise.
 Terms must be clearly defined.
E.g.
“Gastroesophagitis”
 In certain sciences (e.g. physics), the
language is often mathematical.
stomach “food pipe” inflammation
“Heartburn”
The Language of Science

3.  Observations can be obtained directly (by the senses) or indirectly (instruments).
 Human senses are too crude and often unreliable.
 Indirect observations via instruments are often MORE reliable.
 Instruments act as extensions of our senses.
Optical Camera UV Camera
Scientific Observations

4. The Centre of Our Galaxy

5. The Centre of Our Galaxy

6. The Centre of Our Galaxy

8. Scientific Observations
“When you can measure what you are
speaking about, and express it in numbers,
you know something about it; but when
you cannot measure it, when you cannot
express it in numbers, your knowledge is of
a meagre and unsatisfactory kind; it may
be the beginning of knowledge, but you
have scarcely in your thoughts advanced
to the state of Science, whatever the
matter may be.”
- Lord Kelvin
 It is understood that there are always certain limitations in
making observations.
 Observations noted are measured, recorded and presented
 Data may be qualitative or quantitative. Quantitative data is often more
reliable, and preferred in the natural sciences.

9. Hypotheses and experiments
 A “hypothesis” can be best summarized as an “educated guess”.
 The first attempt at explaining a phenomenon.
 A good hypothesis should not only account for all observations made, but be
capable of predicting future observations – this in turn sets up the possibility for
experiment.
E.g. Einstein’s General Relativity explained gravity as a warping of spacetime.
One of the predictions made was that light traveling close to a massive object should
bend as it travels through curved space.

11. Hypotheses and experiments
 If a hypothesis remains unsupported by evidence or becomes disproven, it is modified or
discarded.
 Most hypotheses in science turn out to be wrong.
 To assess the validity of a hypothesis, experiments have to be designed that provide new
observations.
 Experiments must have a control. Controlled experiments ensure that only one variable is
tested at a given time. There are many forms of controlled experiments e.g. the
“double-blind” clinical trial.
 Hypotheses that accumulate evidence in their favour (and withstand attempts at
disproof) are strengthened, and those that grow in their ability to explain and predict
phenomena begin to be regarded as theories.
Video: The Strange Powers of the
Placebo Effect

12. Theories
 In Science the word “theory” means the best explanation available, supported by
evidence, for a phenomenon or set of phenomena. This is very different from the
popular usage of the word “theory” (something uncertain, tentative explanation),
which simply means hypothesis.
 Theories are usually complex and detailed.
 Can take many forms.
 Supported by large amounts of evidence.
“Only” a theory?

13. Theories
General Relativity
(the modern
explanation of gravity
as a warping of
spacetime)
Special Relativity
(observers moving at
different speeds will
experience space and
time differently)
Examples:

14. Theories
Quantum Theory
(modern explanation for
the behaviour of atoms and
subatomic particles)
Theory of Evolution
(foundation of biology)
Our best scientific explanation will always be called a theory, no matter how
much evidence is collected!
Examples:

15. Laws
 The “laws” of nature are the rules that govern the universe (order, cosmos).
 The term law simply means “relationship”. Relationships between phenomena that
are constantly observed without fail are often described as laws.
 Unlike theories, laws simply describe the relationship, they never explain it.

16. Laws
 Because laws describe simple relationships in nature that are always followed, they
are often expressed mathematically.
 Although the term “law” sounds stronger than “theory” in common usage, it is a
common misconception that theories eventually turn into laws.
 Laws are descriptive whilst theories are explanatory. Both are equally supported by
evidence and both are used to advance our understanding of the world and
develop technologies.

17. Video: Fact vs Theory vs. Hypothesis vs. Law… Explained

18. Models
 A model is a representation of the real world.
 Since nothing in science can be claimed with absolute certainty,
models are constructed (both physically and theoretically) by which
an object or process is best understood at the time.
 Models evolve with emerging scientific knowledge
e.g. Model of the Atom

19. The Scientific Meaning of “Fact”
 Remember that there is no absolute certainty in science.
 Something said to be "factual" in science must be supported by large amounts of
evidence.
 A "fact" can take many forms – from simple statements to complex theories.

20.  Thought experimentation is a philosophical practice. On its own,
it is not science. However, it is often used in the early stages
of scientific investigation
 Well-structured, well-defined hypothetical situations (“What might
happen if...?”)
 Sometimes lead to profound scientific breakthroughs.
Examples:
Galileo’s Ship
(classical relativity)
Einstein: “What would I
observe if I rode along a
beam of light?”
(special relativity)
Schrodinger’s Cat
(quantum weirdness)
Thought Experiments