1. CHAPTER 2 Science, Matter, Energy, and Systems

2. Core Case Study: A Story About a Forest
Hubbard Brook Experimental Forest in New Hampshire
Compared the loss of water and nutrients from an uncut forest (________________ site) with one that had been stripped (____________________ site) for three years
Stripped site:
30-40% more ________________
_________ more loss of nutrients
control
experimental
runoff
6 to 8 x

3. The Effects of Deforestation on the Loss of Water and Soil Nutrients
Figure 2.1: This controlled field experiment measured the effects of deforestation on the loss of water and soil nutrients from a forest. V–notched dams were built at the bottoms of two forested valleys so that all water and nutrients flowing from each valley could be collected and measured for volume and mineral content. These measurements were recorded for the forested valley (left), which acted as the control site, and for the other valley, which acted as the experimental site (right). Then all the trees in the experimental valley were cut and, for 3 years, the flows of water and soil nutrients from both valleys were measured and compared.
Fig. 2-1, p. 31

4. Hubbard Brook Ecosystem Study
dedicated to long term forest and stream ecosystem studies

5. 2-1 What Do Scientists Do?
Concept 2-1 Scientists collect data and develop theories, models, and laws about how nature works.

6. Science Is a Search for Order in Nature (1)
Science is a human effort to discover how the physical world ____________
Makes use of the ______________________ to answer questions and solve problems
People use these methods everyday while making decisions
works
scientific method

7. Nothing happens when I try to turn on my flashlight.
Observation:
Nothing happens when I try to turn on my flashlight.
Question: Why didn’t the light come on?
Hypothesis: Maybe the batteries are dead.
Test hypothesis with an experiment: Put in new batteries and try to turn on the flashlight.
Result: Flashlight still does not work.
New hypothesis: Maybe the bulb is burned out.
Figure 2.3: We can use the scientific process to understand and deal with an everyday problem.
Experiment: Put in a new bulb.
Result: Flashlight works.
Conclusion: New hypothesis is verified.
Fig. 2-3, p. 33

8. Use hypothesis to make testable predictions
Identify a problem
Find out what is known
about the problem
(literature search)
Ask a question to be
investigated
Perform an experiment
to answer the question
and collect data
Analyze data
(check for patterns)
Scientific law
Well-accepted
pattern in data
Propose an hypothesis
to explain data
Use hypothesis to make testable predictions
Perform an experiment
to test predictions
Test
predictions
Make testable
Accept
hypothesis
Revise
Scientific theory
Well-tested and
widely accepted
hypothesis
Stepped Art
Fig. 2-2, p. 33

9. Bormann and Likens’ problem?
__________ of water and soil nutrients from cut over forests
Find out what is known about the problem
search scientific ________________ for what is already know…scientists include these findings in the ________________ part of their research papers
Ask a question to investigate
How does clearing forested land affect its ability to store water and retain soil nutrients?
loss
literature
introductory

10. Collect data to answer the question
Information needed to answer the question
Propose a hypothesis to investigate
Scientific hypothesis – possible _________________ of what scientists observe in nature or in the results of their experiments
Make testable projections
If the nutrient loss hypothesis was valid for nitrogen, the soil should also lose other nutrients like ________________
explanation
phosphorus

11. Test the projections with further experiments, models, or observations
Model – approximate ____________________ or simulation of a system
computer models can be used to enter or change data and view expected results
______________ or _______________ the hypothesis
Scientists do not use the word “prove”…why do you think that is?
representation
accept
reject
There are always uncertainties and the
possibility that new results will alter findings

12. Bormann and Likens’ theory…
Scientific theory – a _________________ and widely accepted scientific hypothesis or group of hypotheses
Bormann and Likens’ theory…
Trees and other plants ___________________ and help to retain water and nutrients needed by the plants for their growth
well-tested
hold the soil in place

13. Characteristics of Science…and Scientists
Four important features of the scientific process are…
_________________
Peer review – involves scientists openly publishing their detailed methods and results and allowing other scientists in the same field to _________________ their work
curiosity
skepticism
reproducibility
evaluate

14. Characteristics of Science…and Scientists
Critical thinking is also important to science
Be skeptical
Look at the evidence and evaluate it…especially important in today’s ______________ age where we can be exposed to unreliable data
Identify and evaluate or personal assumptions, __________, and beliefs
“A great many people think they are thinking when are merely rearranging their prejudices.”
- William James, American psychologist
Internet
biases

15. Characteristics of Science…and Scientists
__________________ is also important to science
“ Most major scientific advances are made by creative people who come up with new and better ways to help us understand how the natural world works”
- Albert Einstein, physicist
Creativity

16. Science Focus: Easter Island Revisions to a Popular Environmental Story
The story of Easter Island has been used in textbooks as an example of how humans can seriously degrade their own life support system
New research has led to some new conclusions

17. Science Focus: Easter Island Revisions to a Popular Environmental Story
First, Polynesians arrived on the island ________ years ago, rather than 2,900 years ago
Population size probably never exceeded __________ contrary to earlier estimates of ____________
In addition to using resources unsustainably, European visitors likely exposed the islanders to new ________________
800
3,000
15,000
diseases

18. Science Focus: Easter Island Revisions to a Popular Environmental Story
And why did the trees never grow back?
Hypothesized that rats overpopulated and devoured the tree _________
seeds

19. Scientific Theories and Laws Are the Most Important Results of Science
Facts and data are essential to science, but its real goal is to develop theories and laws…
They help us to understand and _____________ how the world works
Scientific theories should NOT be taken lightly
____________ tested
Supported by ______________ evidence
Accepted by _________ scientists in a particular area
Scientific law, law of nature
explain
well
much
most

20. Scientific Theories and Laws Are the Most Important Results of Science
Scientific law, ____________________
well tested and widely accepted description of what we find happening repeatedly in nature in the same way
Ex: Law of gravity…all objects fall to the earth’s surface at predictable speeds
The theory of gravity goes into more detail _______________ why that happens
Law of nature
explaining

21. Scientific Theories and Laws Are the Most Important Results of Science
So when someone says, “oh, that’s just a theory,” what might you infer about their understanding of science?
Might not understand the amount of testing
that goes into developing theories
Or might not be familiar with the expert
peer review process
Biased? Trying to manipulate you?

22. The Results of Science Can Be Tentative, Reliable, or Unreliable
Tentative science, ____________ science
Not yet widely tested and accepted by peer review
Often in the news and sometimes ___________________
Reliable science
Widely accepted by most scientists who are considered experts in a given field…called scientific _________________
Unreliable science
Discarded as a result of __________________
frontier
controversial
consensus
peer review

23. Science Has Some Limitations
Scientists cannot prove anything absolutely because there is always some degree of __________________ in measurements
Instead, try to establish that a result is at least _______ probable
Humans are not totally free of _________
Many natural systems involve a huge number of ___________________
uncertainty
90%
bias
variables

24. Science Has Some Limitations
________________ tools and ________________ are often used…ex: it would be impossible to accurately measure erosion rates on every inch of the planet
Sample sizes must be ____________ enough to provide accurate results
Testing ________________ sites or locations also increases the validity of your results
Statistical
sampling
large
multiple

25. Science Has Some Limitations
Example: When you flip a coin, what is the probability that it will land head up?
You test this and get the following results…7 out of 10 flips were heads up. What went wrong?
5. Science does not address ______________ or morality
50%
Not enough flips…sample size is too small
ethics

26. Review Questions Well-tested, but not “proven”
What is important to know about scientific theories?
What are four important features of the scientific process?
Well-tested, but not “proven”
Peer-reviewed by experts
Scientific consensus
curiosity
skepticism
reproducibility
peer-reviewed

27. Review Questions Yes No, we use it to solve problems or to understand
Does science have limitations? Does that make it unuseful?
Yes
No, we use it to solve problems or to understand
the physical world better