Interrelated Scientific Principles
Matter, Energy and Environment
Part 1: What is Science?
1. The Nature of Science
- Not a religion! Why?
- Science is a process used to solve problems or develop an
understanding of nature.
- Science involves testing possible answers to questions.
2. Basic Assumptions in Science
- There are specific causes for events observed in the natural world
- The causes can be identified
- There are general rules or patterns that can be used to describe
what happens in nature
- An even that occurs repeatedly probably has the same cause each
time
- What one person percieves can be perceived by others
- The same fundamental rules of nature apply regardless of where
and when they occur
3. Scientific Method
- Careful observation
- Ask questions about observed events
- Propose possible solutions to questions (hypotheses)
- Rigorous testing to see if proposed hypotheses are valid
- Science changes: new techniques, must be open to new information
& ideas
- Submit ideas to the scrutiny of others (communication:
publication and meetings)
4. Elements of the Scientific Method (Fig. 4.1)
5. Constructing Hypotheses
- Definition: a hypothesis is a statement that provides a possible
answer to a question or an explanation for observations that can be
tested.
6. Testing Hypotheses
Experiment
- Repeatable: needs to be designed so the researcher or someone
else can do it again, the same way
- Controlled: vary only 1 or 2 conditions (variables) such as light
or temperature
- Replication: need to have several experimental units that are
treated the same
- Control Group: an equal number of units that have all
variables held the same
7. HUH? - Examples
- Design an experiment to test the effect of short day length on
plant growth.
- Variable = day length
- Control: grow 5 plants in 5 pots at the typical 12 hours of
light and 12 hours of dark.
- Experiment: grow 5 plants in 5 pots under a day length of 6 hours
of light, 18 hours of dark.
- All other conditions are the same: soil, temperature,
watering regime, type of plant, age of plant.
8. Experimental Conditions
- Control: 12/12 light/dark
- Experimental treatment: 6/18 light/dark
- Replication: 5 controls, 5 treatment
- Hypothesis to be tested: day lengths less than 12 hours
will affect plant growth.
9. Development of Theories and Laws
- Theory: a widely accepted, plausible generalization about
fundamental concepts in science that explains why things happen.
- Example: kinetic molecular theory: all matter is made up of
tiny, moving particles.
10. Scientific Law
- Law: a uniform or constant fact of nature that describes what
happens in nature.
- Examples - Law of conservation of mass: matter is not gained or
lost during a chemical reaction.
11. If no one knows about it, it didn’t happen.
- Science progresses only when the results of experiments are
communicated
- Informal: email, letters, phone conversations
- Formal: meetings, presentations, journal articles
12. Journals: popular science, reviews, primary literature
13. Pseudoscience
- A deceptive practice that uses the appearance or language of
science to convince, confuse or mislead people into thinking that
something has scientific validity when it does not.
- Check out: www.quackwatch.com
14. How to tell a quack medical device (from Quackwatch.com)?
* It is said to use little-known energies that are
undetectable by ordinary scientists.
* It can diagnose or cure people living miles away.
* It has a convoluted yet scientific-sounding name.
* It was invented by a "world famous" doctor that is
not actually well known.
* It has bright lights that serve no apparent
purpose.
* It has knobs and dials that serve no practical
purpose.
* It shakes, rattles, rolls, sucks, shocks, or warms
your body.
* It supposedly can cure just about anything.
* It is available only through the mail or at
special outlets.
* You can't find one at a regular doctor's office.
* The manufacturer isn't exactly sure how or why it
works.
* To get results, the patient must face a certain
direction or use the device only at unusual times.
* You're supposed to use it even if there's nothing
wrong with you.
* The FDA has outlawed it.