1. Nature of Science
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2. Understanding Science
Objectives:
Define scientific inquiry
Explain the results of scientific investigations
Explain how a scientist can minimize bias in a scientific investigation
Understanding Science

3. Scientific Explanations
Look at page NOS 2 and answer the three questions
How can science provide answers to your questions about the world around you?

4. What Is Science? What is science?
When do non-professional scientists use scientific methods?
What abilities might you use to explore questions you have about the natural world?

5. What Is Science?
Science: the investigation and exploration of natural events and of the new information that results from those investigations

6. Branches of Science Three major fields of science
Most scientists choose to focus on one of the three
Life Science
Earth Science
Physical Science

7. Scientific Inquiry Scientific method has several steps Ask questions
Make observations
Using one or more of your senses to gather information
Draw inferences
A logical explanation of an observation that
is drawn from prior knowledge or experience

8. Scientific Inquiry Hypothesize Predict
Combines observations and inferences
A testable statement that proposes an explanation about an observation
Predict
Using the hypothesis to state what will
happen next in a sequence of events

9. Scientific Inquiry Test Your Hypothesis Analyze Results
Design an experiment to test your hypothesis
May need to revise hypothesis if the prediction is not confirmed
Analyze Results
Organize data to find patterns
Graphs, classifications, models, etc. help

10. Scientific Inquiry Draw Conclusions Communicate Results
Determine whether you support or reject your hypothesis
It is okay to reject your hypothesis!
Experiment needs to be repeated to be sure
Communicate Results
How could you share results?

11. Scientific Inquiry Check your knowledge! What is scientific inquiry?
What is a hypothesis?
How might a hypothesis be tested?

12. Results of Scientific Inquiry
Many outcomes, including:
Technology
New materials
Possible explanations

13. Scientific Theory and Scientific Laws
“Common” Theory: untested idea
Scientific Theory: explanation of observations or events based on knowledge gained from many observations and investigations
Considered the best explanation unless disproved

14. Scientific Theory and Scientific Laws
Scientific Law: Describes a pattern or event in nature that is always(?) true
Doesn’t explain why something occurs, just how
See table on pg. NOS 9

15. Skepticism in Media Are reporters scientists?
It is important to be skeptical (not the same as dismissive)

16. Evaluating Scientific Evidence
Most important skill: critical thinking
Comparing what you already know with the information you are given in order to decide whether you agree with it
Minimizing bias is also important
See pg. NOS 10 to explore how to
minimize bias

17. Evaluating Scientific Evidence
Science cannot answer EVERYTHING
“Which color is the prettiest?”
“Which political party is the best?”
Any others?

18. Safety in Science
Ethics are important, especially when dealing with living things
Remember safe practices!

19. Review Key Concepts Vocab What is scientific inquiry?
What are the results of scientific investigations?
How can a scientist minimize bias in a scientific investigation?
Vocab
Science
Observation
Inference
Hypothesis
Prediction
Technology
Scientific theory
Scientific law
Critical thinking

20. Measurement and Scientific Tools
Objectives:
Explain the difference between accuracy and precision
Explain when significant digits should be used
Identify tools used by life scientists
Measurement and Scientific Tools

21. SQUIRREL!
Look on pg. NOS 12. How would you describe the squirrel’s activity?
How would you explain the squirrel’s activity?

22. Description and Explanation
Description: Summary of observations
Explanation: Interpretation of observations based on prior knowledge

23. The International System of Units
1960: Scientists adopted a universal system of measurement
Called the International System of Units (SI)
Why is this important for scientists?

24. The International System of Units
Base units are used to make measurements
Length: meter (m)
Mass: kilogram (kg)
Time: second (s)
Electric current: ampere (A)
Temperature: Kelvin (K)
Substance amount: mole (mol)
Light intensity: candela (cd)

25. The International System of Units
Prefixes can be added to a base unit’s name to make it larger or smaller
Uses base powers of 10
Mega (M): 1,000,000
Kilo (k): 1,000
Hecto (h): 100
Deka (da): 10
Deci (d): 0.1
Centi (c): 0.01
Milli (m): 0.001
Micro (μ):

26. Precision and Accuracy
Accuracy: description of how close a measurement is to its accepted value
Precision: how similar or close measurements are to each other
You can average measurements to be more accurate
See NOS 14

27. Significant Digits
Number of digits known for certain plus one estimated digit
Four rules
All nonzero numbers are significant
Zeros between nonzero digits are significant
Final zeros used after the decimal point are significant
Zeros used solely for spacing the decimal point are not significant. The zeros only indicate the position of the decimal point

28. Try It!
100
100.0
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29. Scientific Tools When would you use these? Puzzle teach!
Science journal
Balances
Thermometer
Glassware
Compound microscope
Computers
Magnifying lens
Slide
Dissecting Tools
Pipette

30. Review Key Concepts Vocab
What is the difference between accuracy and precision?
Why should you use significant digits?
What are some tools used by life scientists?
Vocab
Description
Explanation
International System of Units (SI)
Accuracy
Precision
Significant digits

31. Case Study Objectives: Contrast independent and dependent variables
Explain how scientific inquiry is used in real-life scientific investigations
Case Study

32. Biodiesel from Microalgae
Our main source of energy is fossil fuels
We are using it up!
Scientists want to find a way to use protists to make biodiesel
Microalgae are plantlike protists; they undergo photosynthesis

33. Designing a Controlled Experiment
Variable: any factor that can have more than one value
Dependent variable: factor measured or observed in an experiment
Independent variable: the factor being changed to test
Constants (controls): Factors that remain the same

34. Designing a Controlled Experiment
A controlled experiment has two groups: an experimental group and a controlled group
Experimental group receives the factor under study

35. Biodiesel
Early 1900s: Rudolph Diesel created the first diesel engine—it ran on peanut oil
Petroleum eventually eliminated much of peanut’s use due to cost
Oil-rich crops (soybeans and others) can be used as a source of biodiesel
Reduces the amount of food available

36. Aquatic Species Program
1970s: U.S. Dept. of Energy began the Aquatic Species Program to reduce air pollutants
Idea was that aquatic organisms that use photosynthesis could reduce CO2 produced by coal plants
Scientists noticed that some produced large amounts of oils, so the program shifted

37. Which Microalgae? Microalgae Facts
Live in water
Use photosynthesis to make sugar
Require light energy
Extra sugar is converted to oil
Scientists found over 3000 species of oil-producing algae!

38. Which Microalgae? Narrowed it down to 300
Tolerance to acidity, salt, and temperature
Green microalgae and diatoms show most promise
No algae is going to be perfect for all climates

39. Oil Production in Microalgae
Scientists wanted to know if they could increase oil production in algae
Tried starving them of nitrogen or other nutrients
Increased, but algae did not grow as large, causing no net gain

40. Outdoor Testing vs. Bioreactors
Cooler outdoor temps = smaller microalgae
Scientists are working on developing low-cost bioreactors, such as on NOS 23

41. Increasing Oil Yield
Research was testing many hypotheses—they were educated guesses!
Another hypothesis was to make sure light could reach ALL algae
Which algae typically received light?

42. Bringing Light to Microalgae
Experimental Group
Light rods were inserted into the water in a bioreactor to provide artificial light to algae
The next trick is to do so in a pond
What might be some problems?

43. Bringing Light to Microalgae
Experimental Group
Another idea in ponds is to use paddlewheels to stir the algae
How will this have an effect on light?

44. Why Grow Microalgae? Fossil fuels are running out
Fossil fuels also contribute to climate change
Why aren’t we doing this?
COST
Some scientists are working to use microalgae to “scrub” CO2 from coal plants to reduce emissions AND produce fuel

45. Review Key Concepts Vocab
How do independent and dependent variables differ?
How is scientific inquiry used in a real-life scientific investigation?
Vocab
Variable
Dependent variable
Independent variable
Constants