1. Unit 1 Notes Intro to Biology, Experimental Design & The Scientific Method

2. Scientific Investigation vs Technological Design
Scientific Investigation – process followed to determine the relationship between the independent and dependent variable described by the hypothesis
Goal is to answer a question, perhaps advance the knowledge of science
Did using this new fuel help lower pollution?
Technological Design – process followed to design products or processes to meet specific needs
Goal is to create a specific outcome, perhaps advance the standard of living in societies
We have created a lower pollution emitting car

3. Scientific Investigation vs Technological Design
Identifies a problem – asks a question
Identifies a problem or need
Researches related information
Designs an investigation or experiment
Designs a process or a product
Conducts the investigation or experiment – repeated trials
Implements the design or the process – repeated testing
Analyzes the results
Evaluates the conclusion – did the results refute or verify the hypothesis
Evaluates the process or product – did it meet the criteria
Communicates the findings
Communicates the product or process

4. Science and Society
Ethics – moral principles and values held by humans
What role do ethics play in scientific research and results?
Can science answer all questions?
Technology – application of scientific research to address society’s needs
Can technology solve all problems?

5. Types of Research Two main types Quantitative (Quantity)
Uses controlled experiments
Results are numerical data
Qualitative (Quality)
Descriptive
Relies on observations of situations out of scientist’s control
Results are descriptions of observations
Often an important tool for wildlife studies

6. Methods of Biology
The series of steps used by scientists to gather information and answer questions is called the Scientific Method.
If you had a question or a problem to solve, what steps would you go through to resolve it?

7. Scientific Method State the Problem
Take note of something no one has seen before or has yet to explain

8. Scientific Method Gather Information
Observation - Gathering information using your senses
Information gathered should be:
Credible - trustworthy
Accurate - correct – based on supported data
Relevant - applicable, related to the topic of the investigation
These sources could be
Previous scientific investigations
Science journals
Textbooks
Other credible sources, such as scientifically reliable internet sites.

9. Observation vs. Inference
Inference – making a judgment based upon an observation and past experience
Fact or Fiction?
An inference is making a judgment based upon an observation and past experience
Not all inferences can be supported by direct observation (p.373 Holt – Cheetah)
Scientists “infer” past events by looking at fossils, remains, traces of organisms that lived in the past. Scientists look for patterns (p.382 Holt-Cheetah).
What do you think is more CAR (Credible, Accurate, Reliable) scientific, Observation or Inference?

10. Make at least 3 observations about this picture.
Make at least 3 inferences about this picture.

11. Make three observations and inferences with this new information
Does the new information change your responses?

12. What does this final picture do to your previous inferences?

13. Scientific Method Form a Hypothesis
Create a testable explanation for the situation that you observed

14. Scientific Method Test the Hypothesis - Experiment
Design an experiment
An organized procedure for collecting information under controlled conditions
The experiment will have two groups
Control – all conditions are kept the same
Experimental – conditions match that of the control except for the one factor being tested

15. Scientific Method Testing…
An important part in the experiment design is the sample size – the number of test subjects
A large sample size increases the reliability of results
A large sample size decreases the effect of errors on the outcome
How could having a larger sample size help the following experiments?
Tim tested the effect of fertilizer on two plants The one with fertilizer grew taller than the one without it.
Suzy developed a drug to lower cholesterol She gave it to two patients who later died.

16. Scientific Method Testing…
The condition that is changed in the experiment is the independent variable – it will be the only thing that can affect the outcome
The outcome observed is the dependent variable – it depends upon the changes made to the independent variable
Note: Some experiments cannot be controlled so other observation methods have to be used
Example: wildlife study

17. Independent vs. Dependent Variables
Mark the independent (cause) and dependent (effect) variable in each situation
Suzy wanted to test how changing her diet affected her weight.
The track team members that ran extra laps at practice ran better times at the next meet.
Jack planted half of his roses in the shade and the other half in the direct sunlight and measured the differences in plant height and bloom production.

18. Scientific Method Record and Analyze Data Record Data
Data – information obtained from experiments
Observations
Results
Data should be precise and accurate
Precision – the degree to which measurements made in the same way agree with each other
If you and I measure it, do we get the same thing?
Accuracy – the degree to which the value measured agrees with the true or accepted value
Even if we both got the same thing, did we measure it correctly?
Data must then be analyzed or interpreted
Graphs
Tables
Charts

19. Effects of Fertilizer on Plant Height
Tables
All tables must include the following
Title
Clearly labeled columns and rows
Labeled units
Data should show relationship between independent and dependent variable
Effects of Fertilizer on Plant Height
Amount of Plant Fertilizer (g) Independent
Height of Plant (cm) Dependent 2 12 6 20 10 4

20. Graphs All graphs must include the following Title
A label for each axis
Labeled units
Legend
Data properly depicted
* Independent on x-axis
* Dependant on y-axis
y-axis
x-axis

21. Graphs What type of graph should I use? Line
For continuous quantitative data
Height of plant over time
Stock market prices over time
Line graph relationships
Direct variation – one variable increases as the other increases (or decreases as the other decreases)
Inverse variation – one variable decreases as the other increases

22. Graphs Bar For non-continuous data (usually in categories)
Number of people who watch each TV show surveyed
Pie
For data that are parts of a whole
Percentage of those polled that chose each TV show

23. International System of Measurement (SI)
Basic units of measurement
Length – meter (m)
Tool – ruler or meter stick
Volume – liter (L)
Tool – graduated cylinder
Mass – gram (g)
Tool – triple-beam balance
Time – second (s)
Tool - stopwatch
Temperature – Kelvin (K) [We will most often use Celsius (°C)]
Tool - thermometer

24. King Henry Died By Drinking Chocolate Milk
Units of Measurement
Metric system – based on 10
kilo (k) – kilometers (km) 1000 meters
hecto (h) – hectometers (hm) 100 meters
deca (da) – decameters (dam) 10 meters
Basic unit (m, L, g) – meter (m) 1 meter
deci (d) – decimeter (dm) 0.1 meter
centi (c) – centimeter (cm) 0.01 meter
milli (m) – millimeter (mm) meter
King Henry Died By Drinking Chocolate Milk

25. Converting one metric unit to another
k h da Basic unit d c m
(m, L, g)
To convert from one unit to another, move the decimal same direction and number of places the units are from each other
12 kilometers is ?? centimeters
centimeters are 5 places to the right
1,200,000 cm
134 decigrams is ?? hectograms
hectograms are 3 places to the left
0.134 hg

26. Accuracy vs. Precision Correct vs. Consistent
In the fields of science, engineering, industry, and statistics, the accuracy[1] of a measurement system is the degree of closeness of measurements of a quantity to that quantity's actual (true) value. The precision[1] of a measurement system, also called reproducibility or repeatability, is the degree to which repeated measurements under unchanged conditions show the same results.[2] Although the two words precision and accuracy can be synonymous in colloquial use, they are deliberately contrasted in the context of the scientific method.
A measurement system can be accurate but not precise, precise but not accurate, neither, or both. For example, if an experiment contains a systematic error, then increasing the sample size generally increases precision but does not improve accuracy. The result would be a consistent yet inaccurate string of results from the flawed experiment. Eliminating the systematic error improves accuracy but does not change precision.
A measurement system is considered valid if it is both accurate and precise. Related terms include bias (non-random or directed effects caused by a factor or factors unrelated to the independent variable) and error (random variability).
The terminology is also applied to indirect measurements—that is, values obtained by a computational procedure from observed data.
In addition to accuracy and precision, measurements may also have a measurement resolution, which is the smallest change in the underlying physical quantity that produces a response in the measurement.
In numerical analysis, accuracy is also the nearness of a calculation to the true value; while precision is the resolution of the representation, typically defined by the number of decimal or binary digits.

27. Scientific Method Always Report Results! State a Conclusion
Did the data support the hypothesis?
If yes…
Verify results
Can the experiment be repeated?
Do other scientists support the findings?
If no…
Repeat the experiment
Revise the experiment
Develop a new hypothesis

28. Scientific Method Repeat No matter what happened!
Fact – Observable phenomenon that can be confirmed by scientists many times
Form a Theory – a hypothesis tested over a long period of time, supported by separate experiments

29. Fact vs. Theory Which is Fact…Which is Theory?
Dinosaurs were cold blooded.
The caterpillar is 3.5 cm long.

30. Identifying Study Components
A student noticed that when a dog is cut, the dog periodically licks its wounds. Usually after a few days, the wound begins to heal without ever showing signs of infection. The following steps outline the student's line of reasoning:
I wonder why the dog's wound doesn't become infected.
The dog's saliva must prevent the growth of infection-causing bacteria.
I'll obtain a bacterial culture and grow the same kind of bacteria in two identical culture dishes. Once the bacteria start growing, I'll add dog saliva to only one of the dishes and leave the other alone. I'll cover both dishes. Then I'll observe what happens each day for a week.
Even after adding the dog saliva to one of the dishes, the bacteria continued to grow in both dishes over the course of the week. However, the bacteria in the treated dish grew more slowly than the bacteria in the untreated dish.
I think I'll try something else. I'll start with two identical culture dishes, as before, and use the same kind of bacteria in each dish, but this time I'll treat one dish with dog saliva before I add the bacteria. I'll observe what happens each day for a week.
What was the student’s hypothesis?
Which step described the experimental set up?
Identify the control
What is the independent variable?
What is the dependent variable?
What data did the student collect?
What is a possible conclusion from this experiment?
Is that conclusion a fact or an inference?

31. Identifying Study Components
A student noticed that when a dog is cut, the dog periodically licks its wounds. Usually after a few days, the wound begins to heal without ever showing signs of infection. The following steps outline the student's line of reasoning:
I wonder why the dog's wound doesn't become infected.
The dog's saliva must prevent the growth of infection-causing bacteria.
I'll obtain a bacterial culture and grow the same kind of bacteria in two identical culture dishes. Once the bacteria start growing, I'll add dog saliva to only one of the dishes and leave the other alone. I'll cover both dishes. Then I'll observe what happens each day for a week.
Even after adding the dog saliva to one of the dishes, the bacteria continued to grow in both dishes over the course of the week. However, the bacteria in the treated dish grew more slowly than the bacteria in the untreated dish.
I think I'll try something else. I'll start with two identical culture dishes, as before, and use the same kind of bacteria in each dish, but this time I'll treat one dish with dog saliva before I add the bacteria. I'll observe what happens each day for a week.
What was the student’s hypothesis?
Which step described the experimental set up?
Identify the control
What is the independent variable?
What is the dependent variable?
What data did the student collect?
What is a possible conclusion from this experiment?
Is that conclusion a fact or an inference?