1. Question of the Day
1.) Explain how genetic engineering can improve food supplies.
2.) Describe one problem that scientists must overcome to develop a vaccine of HIV.
3.) Explain how gene therapy might be used to treat cystic fibrosis.

2. Scientific Process
Unit 1

3. Objectives: Describe the stages common to scientific investigations.
Distinguish between forming a hypothesis and making a prediction.
Differentiate a control group from an experimental group and an independent variable from a dependant variable.
Define the word theory as used by a scientist.

4. Observation: The Basis of Scientific Research
All scientists, have a particular way of investigating.
There are particular steps that need to be followed and it makes it quite interesting.
The path leads you to the answer!

5. Solving Scientific Puzzles
During the summer of 1988, David Bradford reflected on the silence around him.
Spent the summer looking for a species of frog in the lakes of the Sequoia and Kings Canyon National Parks.
Frogs were always there and very prevalent since records had been kept.
However, in 1988, they had disappeared from 98% of the lakes.

6. Solving Scientific Puzzles
Observation
The act of noting or perceiving objects or events using the senses.
As Bradford reported these observations, other scientists agreed with him with their observations of other amphibians.
Amphibians have been around for >370 million years, why?
This disappearance from their natural homes = alarm.
Amphibians are sensitive to environment.
Their moist skin absorbs chemical from the water.

7. Solving Scientific Puzzles
B/w , John Harte (Cal Berkley) was also studying amphibians.
Tiger Salamanders
Live in ponds high on the western slopes of the Rocky Mountains in CO.
Their numbers had decreased by 65% over those years.
Harte was looking for the answer as to why this was happening.
Started a scientific investigation.
Key to this is that he did not form a conclusion, but a hypothesis.

8. Stages of Scientific Investigations
There is no steadfast way of the “scientific method.”
Still there are common stages:
Collecting Observations
Asking Questions
Forming Hypotheses
Making Predictions
Confirming Predictions
Drawing Conclusions

9. Stages of Scientific Investigations
Collecting Observations
This is the core of scientific investigation
Harte studied the population for years
Learned everything about them:
How they eat
Behaviors
Reproduction
Perfect environments
Students collected water samples.
Made frequent visits
Realized population was decreasing.
Kept careful records of the lake, population, overall conditions

10. Stages of Scientific Investigations
Asking Questions
Observations lead to questions
Harte questioned why the number of salamanders was dropping
Talked to other scientists, made further careful observations, and read scientific reports
Answered many of his questions through observations but…
Some key questions remained unanswered.
In the natural world, the moisture that falls as rain and snow is very slightly acidic.
In Rocky Mountains the moisture is high in sulfuric acid from power plants
Acid precipitation released into mountain ponds
When snow melts, goes into lakes.

11. Stages of Scientific Investigations
Forming Hypotheses and Making Decisions
A hypothesis is an explanation that might be true – a statement that can be tested by additional observations that can be tested by additional observations or experimentation.
A hypothesis is not a guess
It is an educated guess based on what is already known
Harte formed two hypotheses:
Acids that were formed in the upper atmosphere by pollutants were falling onto the mountains in the winter snows.
Melting snow was making the ponds acidic and harming the salamander embryos.
A prediction is the expected outcome of a test.
Assuming the hypothesis is correct.

12. Stages of Scientific Investigations
Forming Hypotheses and Making Decisions
Harte predicted:
He would find acid in the ponds after the snow melted.
He also predicted that there would be enough acid in the ponds to harm salamander embryos.
Harte set out to test his hypotheses.

13. Stages of Scientific Investigations
Confirming Predictions
Harte gathered data from many years of observations
Measurement of acidity of the ponds before, during, and after snowmelt
Water samples
pH is explained by a number 0 to 14.
Relative measure of the hydrogen ion concentration within a solution.
Harte found that ponds became more acidic as the snow melted.
For the second hypothesis Harte performed an experiment.
Salamanders lay eggs in the pond after the snow melt.

14. Stages of Scientific Investigations
Confirming Predictions
This was a controlled experiment with an experimental group.
Control Group – Group that receives to experimental treatment.
Both the control and experimental groups are identical with one exception, the variable.
Independent Variable – The factor that is changed.
pH level
Dependent Variable – The factor that is measured.
Number of salamanders that hatched from eggs

15. Stages of Scientific Investigations
Drawing Conclusions
Once all the data is collected and analyzed, conclusions are made that either support or refute the hypothesis.
Supported, NOT proven
Why?
Viewing Conclusions in Context
Write it out properly and report it professionally in accordance with reporting rules.

16. Scientific Explanations
Scientific progress is like erosion, a slow chipping away and weathering.
Models – Hypothetical description…
Theory – A set of related hypotheses that have been tested and confirmed many times by scientists.
Unites and explains a broad range of observations.
Constructing a Theory
Involves considering contrasting ideas and conflicting hypotheses.

17. Critical Thinking
Summarize how scientists use observations, hypotheses, predictions, and experiments in scientific investigations.
What is the difference between the independent variable and dependent variable.
What is the difference in the word theory in science vs. the general sense.
A researcher finds that 90% of salamanders hatch from eggs in water with a pH of 7, 80% at pH of 6, 60% at 5, and 40% at 4. What is the approximate % at pH of 5.5?
55%
61%
70%
85%