1. Chapter 2
How is science done?

2. Types of Sciences There are two basic types of sciences.
Pure Science Applied Science
Answers how - Uses pure
the natural world science works information
to solve problems

3. Types of Sciences
Look at the sciences below and decide if they are pure or applied.
Biology Environmental
Engineering Medicine
Chemistry Physics
Zoology Astronomy

4. The Scientific Method

5. What is it?
It is a process that is used to find answers to questions about the world around us.

6. Is there only one?
No, there are several versions. Some versions have more steps, while others may have only a few.
They all begin with the identification of a problem or a question to be answered based on observations of the world around us and provide an organized method for conducting and analyzing an experiment.

7. What is a hypothesis?
It is an educated guess based on observations and your knowledge of the topic. It has to be testable. Can be written as an “if, then” statement.

8. What is data?
It is information gathered during an experiment. Only observations are done at this time.

9. Identify the Problem What do you want to know or explain?
Use observations you have made to write a question about the problem.

10. Form a Hypothesis What do you think will happen?
Predict the answer to your question.

11. Create an Experiment How will you test your hypothesis?
Design an experiment to test it.

12. Experiment - Variables
Factors that can be changed
Independent variable is changed by the scientist (I change because I am the scientist)
Dependent variable is changed by the independent variable (the data collected during or at the end of an experiment)
Controls: Everything that is held constant.

13. In a good experiment
Only one manipulated variable is tested at a time.
The manipulated or independent variable is changed by the scientist.
The responding or dependent variable is the data collected during the experiment.
All other variables are controls because they are held constant.

14. Perform an Experiment
Follow the steps in your procedure to perform your experiment.
Record data and make observations.

15. Analyze the Data
Is the data reliable? Does the data support your hypothesis?
If the data does NOT support your hypothesis, then Modify the Experiment. Rewrite the experiment to address flaws.
Retest.

16. Communicate the Results
When data supports your hypothesis, write a conclusion that summarizes the important parts of your experiment and the results.
This step is needed to complete the scientific method.

17. Scientific Theory
It is an explanation of why something is observed in nature. This is based on a large body of evidence through research and experimentation.
Examples: Big Bang Theory, Plate tectonics, Atomic theory, Evolution, Global Climate Change due to anthropogenic activities

18. Scientific Theory
Theories may be supported by scientific evidence at the time but may be incorrect. Evidence may change with time because of better technology or a new way to look at the data.
Example: Geocentric theory: earth in middle of solar system to Heliocentric theory: sun in middle of solar system

19. Scientific Law
A description of an observed phenomenon but doesn’t explain why it exists or what causes it. Usually written in a formula.
Example: Gravity Fg = G m1 m2/d2

20. Science has limitations
Scientific research cannot prove anything absolutely.
Scientists are humans and can come with bias about their results. This is why peer review when an experiment is communicated is important.

21. Systems What is a system? Look at page 59, Figure 2-14.
There are inputs, throughputs, and outputs of a system.
List inputs, throughputs, and outputs of ONE of these systems:
human body
forest
a river
Earth

22. What are Systems?
A set of components that function and interact in some way.
Examples of systems: the human body, a cell, a forest, a river, Earth
Systems stop functioning when an element is removed or changed significantly.

23. What are Systems? Components to a system: - inputs -throughputs
-outputs (matter, energy, information)
Examples of outputs: heat, waste, products from an assembly line

24. Systems

25. Feedback
Is matter, energy, or information that is put back into the system as input
It can cause an increase or a decrease change in the system

26. Feedback Loop Positive feedback
-Input that increases a change to a system
-Causes a system to change further in the same direction
Negative feedback
-Input that decreases a change to a system
-Corrective loop causes the change in the opposite direction from which it is moving

27. Loop examples: Climate change

28. Another positive feedback loop
Fruit Ripening
There is a surprising effect in nature where a tree or bush will suddenly ripen all of its fruit or vegetables, without any visible signal. If we look at an apple tree, with many apples, seemingly overnight they all go from unripe to ripe to overripe.

29. Positive feedback loop cont.
This will begin with the first apple to ripen. Once ripe, it gives off a gas known as ethylene (C2H4) through its skin. When exposed to this gas, the apples near to it also ripen. Once ripe, they too produce ethylene, which continues to ripen the rest of the tree in an effect much like a wave. This feedback loop is often used in fruit production, with apples being exposed to manufactured ethylene gas to make them ripen faster.

31. Loop examples: Predator/Prey

32. Graph of a negative feedback loop

33. Which loop type is this?

34. Question
What could you do if your grade is not what you want in science at the end of grading period one for the next grading period?
What kind of feedback loop is this?
Negative feedback loop, corrective one

35. Loop examples
video on feedback loops