1. What is Science?
Plant Biology 006,
Summer 2012

2. Science is a way of knowing
Science is a way of knowing. It is a formal process of asking questions about the world and seeking explanations.

3. The key element of the scientific method is
hypothetico-deductive reasoning.
So what is that?

4. Hypothetico refers to hypothesis
Hypothetico refers to hypothesis. A hypothesis is a provisional explanation of some phenomenon.

5. Deductive refers to the use of deductive reasoning to test the hypothesis.
Deduction is reasoning from the general premise to the specific observation. It differs from induction, which involves moving from a set of specific facts to a general conclusion.

6. Example:
Hypothesis: All dogs have fleas.
Inductive approach is based on accumulating evidence in
support of the hypothesis. Examine all the dogs you can
find. If you examine enough and they all have fleas, you
can claim that the evidence supports your hypothesis.
However, this approach is vulnerable: even if you
examine ten thousand dogs and they all have fleas, who’s
to say that the ten-thousand-and-first won’t be flea-free?

7. Example:
Hypothesis: All dogs have fleas.
Deductive approach is based on falsifying the hypo-
thesis. If, in the course of your canine examination, you
find even one single dog without fleas, the hypothesis
has been falsified. It is then revised or discarded in favor
of an alternative hypothesis.

8. The hypothetico-deductive method
proceeds by proposing a testable
hypothesis and then trying to falsify it.

9. Figure 1.19 Idealized version of the scientific method

10. Figure 1.20 Applying hypothetico-deductive reasoning to a campground problem

11. Jan Baptista van Helmontca .

12. Figure 1.19 Idealized version of the scientific method
Trees grow larger with passing time.
Why do trees grow larger with passing time?
Trees grow larger by absorbing material from the soil.
If a tree is grown in a pot of soil, the weight of the soil should decrease
as the weight of the tree increases.

13. What happened?
At the end of five years, the willow tree had increased in
weight by 74.4 kilograms.
The soil had decreased in weight by only 57 grams!

14. Figure 1.19 Idealized version of the scientific method
Trees grow larger with passing time.
Why do trees grow larger with passing time?
Trees grow larger by absorbing material from the soil.
If a tree is grown in a pot of soil, the weight of the soil should decrease
as the weight of the tree increases.
Result: the soil did not decrease in weight.

15. Conclusion:
The hypothesis had been falsified: it was demonstrated that plants do not increase in size by absorbing material from the soil.

16. Q. Which of the following best represents an application of the Scientific Method?
A student memorizes the Periodic Table of the Elements
A homeowner checks his fuel tank to see if that’s why his furnace won’t come on
An anthropologists finds a fossil hominid older than any yet known
Geneticists completely sequence the human genome