1. ? What is Science? What does it mean to know something?
How does science differ from other ways of knowing?
Science is tested against observation (empiricism)
Science aims to disprove
Science doesn’t care what the answer is to a question

2. Occam’s Razor: When more than one explanation
agrees with observation, the simpler explanation is
usually right
Albert Einstein - Make everything as
simple as possible,
but not simpler

4. Observation
Observation is the process of gathering information about events
or processes in a careful, orderly way.
Scientists collect data and use data to form inferences
Data are either
Qualitative: Things measured by quality –
eg. Color
Quantitative: Things measured in numbers –
eg. Length, width
An inference is a logical interpretation based
on prior knowledge or experience

5. Induction moves from the specific to the general.
Ex: These 6 elephants are sick, therefore I think
all elephants in this population are sick. Induction
is used to generate hypotheses but never provides
true knowledge. Inferences are inductive.
Deduction moves from the general to the specific.
Ex. I think all the elephants in this population are sick.
I test as many as I can, I find some that are not sick.
Therefore, I can conclude my hypothesis was wrong.
Deductive reasoning is the only logically valid type.
Therefore, science can only disprove.

6. Hypothesis Follows observation and research
The hypothesis is a prediction based on inference
from observation
Hypotheses must be testable to be considered scientific

7. Experiment Experiments are designed to attempt to disprove hypotheses
Remember – Science can only disprove things

8. The language of experiments
Independent Variable – The thing you are interested and manipulate
Dependent Variable – The thing you measure to determine if the
IV matters -- The DV depends on the IV
Control – A part of the experiment that is run without treatment
to determine if observed changes would have occurred anyway
Constants – Things that don’t change during an experiment

9. The language of experiments
If you restate the hypothesis as an if then prediction, it can help you remember these terms
IF I _____ the _______ then ________ will _______
If I _____ the ___IV__ then ___DV__ will __DV___
Ex: If change the temperature then plants will grow
IV = temp DV = plant growth

10. Famous Biology Experiments
Aristotle ( B.C.) observed rats emerging from hay and rags in corner of barn and concluded that the rats (living) arose from the hay and rags (nonliving). He thought that flies could be produced by first killing a bull, then burying it with its horns protruding from the ground. Flies emerged from one of the horns sawed off several days after burial. Aristotle’s interpretation was that life may arise from the nonliving (theory of spontaneous generation).

11. Famous experiments discrediting theory of spontaneous generation
late
1700s
1862
1668

13. Conclusion Experiments either reject hypotheses (prove them wrong)
or fail to reject hypotheses
Experiments never prove anything positively
Experimental results are published
Other scientists try to repeat or refine the experiment
Science works as a self correcting system

14. Theory Those hypotheses that have been repeatedly tested and
have not been rejected are treated with extra weight
Once a system of hypotheses providing a grand explanation
of phenomena reaches the point that it is almost assured
it will never be rejected, we call it a theory
In science the word “theory” means much more than
how it is used in common language
Famous theories include Gravity, Evolution, Relativity
“just a theory” in science means we are as sure of it
as we are gravity