1. What is Science?
Plant Biology 006,
Spring 2016

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. All scientific advances begin with an inquisitive mind carefully observing natural phenomena
The scientific method:
Make observations and ask questions
Develop a hypothesis

4. What is a hypothesis?
A hypothesis is a provisional explanation of some phenomenon.
Scientific hypotheses are never
proven to be true. Rather, they are
subject to testing and if they are not
established to be false, they continue
to be accepted.

5. Science proceeds by the testing of hypo- theses, with the goal of falsifying them (shooting them down). A hypothesis that has not been falsified is allowed to stand as the provisional truth.

6. The scientific method:
Make observations and asking questions
Develop a hypothesis
Use the hypothesis to make predictions
Use experiments to test the hypothesis
Modify the hypothesis based on experimental results

7. Question: How do plants grow? Hypothesis: Plants grow by eating soil.
Jan Baptista van Helmont ca .

8. Figure 1.19 Idealized version of the scientific method
Trees grow larger with passing time.
How is this possible?
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.

9. 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!

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

11. 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

12. Lecture Review, Chapter 1
Define science in your own words.
What is a hypothesis?
Describe how van Helmont’s 5-year tree experiment followed the scientific method.
Give a practical example of use of the scientific method in everyday life.