Nature of Science

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Nature of Science
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Science

• Facts and ideas developed by scientists and the
  methods
• used by scientists to gain information.
• A process of making observations and asking
• questions about those observations.
• Scientists gain knowledge through study and
• investigation.

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Observations

• Data
• recorded observations or any information
  acquired through experimentation
• Types of Observations
• Qualitative
• involves a description of the quality by
  using your senses
• Quantitative
• involves the use of instruments results are
  
• measureable must include a number

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Quantitative or Qualitative ?

• 1. It is about _____ centimeters in
  diameter.
• 2. The flame begins about 1-cm above the top
  of the candle.
• 3. The flame is a shade of blue at its base.
• 4. The length decreased during the observation
  period.
• 5. Immediately around the wick in a region about
  1-cm wide and
• extending about 1-cm above the top of the wick,
  the flame is dark.
• 6. The amount of decrease was about _____
  centimeters per half hour.
• 7. This dark region is roughly conical in
  shape.
• 8. The candle is translucent.
• 9. It is white (or yellow, etc.).

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Scientific Investigation

• Scientific Method
• Series of steps used to answer questions and
  solve problems
• Traditional Steps of the Scientific Method
• Identify the problem
• Gather information
• Make a hypothesis
• Test the hypothesis by experimentation
• Observe, Record Observations (Data)
• Conclusion

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Scientific Investigation

• Scientific investigations do not always proceed
  from
• one step of the scientific method to the next.
• Sometimes steps are
• skipped
• and sometimes they are
• repeated.

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Experimental Design

• Variable
• a factor item in an experiment which when
  changed causes the results of the experiment to
  change
• Independent variable
• factor that is purposefully changed by
  the experimenter
• Dependent variable
• factor that responds, therefore it is
  what is measured
• Controlled variable
• constant factor(s) that are kept the
  same
• throughout the experiment

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Experimental Design

• Testing Groups
• Experimental Group
• the test group where all conditions, except the
  independent variable,are kept the same
• Control Group
• the test group that is used as a standard for
  comparison doesnt include the independent
  variable

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Example
Sam wished to investigate how fertilizer run-off
affects the growth of algae in freshwater lakes
and streams. He set his experiment up in this
way. He placed 900 mL of water into each of five
1000 mL glass beakers. To each beaker he added 5
mL of water from an aquarium which contained a
large concentration of algae. The beakers were
placed under a grow light which was timed to
provide 12 hours of light each day. Liquid
fertilizer was added to the beakers in the
following amounts beaker 1 no fertilizer,
beaker 2 2 mL of fertilizer, beaker 3 4 mL of
fertilizer, beaker 4 6 mL of fertilizer,
beaker 5 8 mL of fertilizer. Each week a
random sample from each of the beakers was
examined under a microscope to get a count of the
number of algae cells present.
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Dependent Variable number of algae cells
Independent Variable amount of
fertilizer Experimental Group beakers with
fertilizer (beakers 2-5) Control Group beaker
without fertilizer ( beaker 1) Controlled
Variables 900 mL of water 5 mL of aquarium
water grow light for 12 hours 1000 mL glass
beakers
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Example
Stephanie conducted an experiment to determine if
the color of a maze would affect the time it took
for a mouse to run through it. She constructed 5
identical mazes of plywood. She painted them
white, yellow, red, blue and green. She purchased
10 young mice at a local pet store. She ran 2
mice through each maze until the mice could run
it twice without making an error, she then
compare the number of runs it took the mice in
each color to learn it
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Dependent Variable number of runs to learn
maze Independent Variable color of
maze Experimental Group mice running in colored
maze Control Group mice running in white
maze Controlled Variables age of mice maze
design
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Example
Researches want to determine the best temperature
for storing batteries. Describe the following
variables you need to consider when performing
the experiment. Independent Variable Storage
Temperature Dependent Variable hours of use
after storage 2 Controlled Variables same type
of battery same expiration date same moisture
(environment)
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Example
Your friend has to plan an experiment for a
science fair. He asks for your help.His topic is
The Strongest Cloth for Backpacks. Describe
the following variables you need to consider when
performing the experiment. Independent
Variable type of fabric Dependent
Variable how long fabric can carry heavy load
without tearing 3 Controlled Variables size of
fabric initial condition of the fabric load
used
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Example
Larry was told that a certain muscle cream was
the newest thing on the market and claims to
double a persons muscle power when used as part
of a muscle-building workout. Interested in this
product, he buys the special muscle cream and
recruits Patrick and SpongeBob to help him with
an experiment. Larry develops a specal
marshmellow weight-lifting program for Patrick
and SpongeBob. He meets with them once every day
for a period of 2 weeks and keeps track of their
results. Before each session Patricks arms and
back are lathered in the muscle cream, while
SpongeBobs arms and back are lathered with the
regular lotion.
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Time Patrick SpongeBob
Initial Amt. 18 5
After 1 Wk 24 9
After 2 Wks 33 17
Control Group SpongeBob Independent
Variable Muscle Cream Dependent
Variable Amount of Marshmellows lifted (
Strength) Controlled Variables Same amount of
cream Cream applied to same area Conclusion Sin
ce both improved their results, it doesnt appear
that the claims for the special cream are true.
If cliams were correct, twe should have seen
Particks a mont double, but not SpongeBobs.
Improvement were likely due to the workout
itself and not the cream
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Scientific Models

• representation of an object or system that make
  concepts easier to understand
• can represent things to small to see or too large
  to observe directly
• can be used to test hypothesis and illustrate
  theories

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Science Lab Reports
A formal lab report should be typed, have page
numbers, and contain all of the following
information in the following order. Every student
is expected to write his or her own report. You
are encouraged to discuss the experiment ,
analysis and interpretation with your classmates
but you are expected to turn in original work.
If any portion of your report is plagiarized from
another student, book or website, you are guilty
of academic misconduct. Take pride in your
work.

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Science Lab Reports

• Title Page
• title should relate to the basic concept involved
  in the lab activity
• be creative - dont use your problem statement
• graphic relating to lab is required
• name, class period and date are required
• Problem
• states very precisely what you want to know
• written as a question
• must include independent and dependent variable

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Science Lab Reports

• Hypothesis
• prediction of how your experiment will come out
• educated guess based on knowledge research you
  have done
• prior to experiment
• expresses relationships between variables
• only valid if testable and supported by evidence
• written as an If,then. because...
  statement
• Materials
• list, in columns, all equipment and quantities
  needed for experiment

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Science Lab Reports

• Procedure
• logical, numerical listing of each step needed to
  conduct experiment
• needs to be clear and precise so anyone could
  repeat experiment without difficulty
• should include illustrations with labels to help
  clarify set-up and/or a particular step
• good grammar, spelling communication skills are
  important
• First step should read Gather materials
• Last step should read Clean up and complete lab
  report
• Data
• Organized presentation of what you have observed
• Quantitative Observations - charts/tables with
  labels and title(s)
• Qualitative Observations - paragraph format
  and/or photos with captions

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Science Lab Reports

• Data Presentation
• Graphs
• Independent Variable placed on horizontal / x
  axis given info purposefully
  changed factor
• Dependent Variable placed on vertical / y
  axis info obtained during the
  experiment response to
  independent variable
• should accommodate at least 75 of paper
• title should include the independent dependent
  variable and appear in the upper part of the
  graph
• legends (keys) should be within the body of graph
  and displayed in a box
• axes are labeled with variable and units as
  follows variable(units)
• consistent intervals used in numbering, or an
  appropriate sign is used to indicate a break
• numbers are neatly written and spaced
  appropriately and logically
• everything (text and numbers), but not actually
  graph, are done in pen

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Science Lab Reports

• Conclusion
• Well written, 3 paragraph minimum, which
  should incorporate any teacher generated
  questions, summarizing findings
• Paragraph 1 Analysis of Hypothesis
• restate problem and answer it based on
  experimental findings
• state whether hypothesis was supported or
  rejected
• present quantitative findings that either
  support or reject hypothesis
• Paragraph 2 Limitations and Weakness of your
  Procedure
• evaluate the procedure that you used
  (equipment, materials, methods)
• describe possible sources of error and
  modifications for improvement
• Paragraph 3 Interpretations of the Data,
  Conclusion Ideas for Further Study
• explain patterns and trends in the data
• explain results using scientific reasoning
  knowledge
• describe other experiments or extensions of
  the lab that you feel would be useful to
  explore the concept further