the scientific method a review. what is the ``scientific method''? organized common sense!...
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The Scientific Method
A review
What is the ``scientific method''? Organized common sense!
•1. Determine the problem.
•2. Research about the problem.
•3. Write a hypothesis, that is a proposed explanation made on the basis of limited evidence as a starting point for further investigation.
•4. Design an experiment to test the hypothesis.
•5.Collect and Analyze the data.
•6. Conclusions : what you learned from the experiment
Simplified … Make observations (vs
inference) Write testable hypothesis Design experiment
(dependent/ind. variables) Collect data (qualitative vs
quantitative) Graph and analyze results
Observationso OBSERVATION: The use of senses to
see and record the world around you.o INFERENCE: Making a conclusion
based on opinion or prior experience.
Hypothesis A statement that attempts
to answer the experimental question.
No longer referred to as an ‘educated guess’; instead, it is a proposed solution.
Hypothesis must be TESTABLE.
Are these good hypotheses? Fresh-water fish taste better. The more expensive a perfume is, the
better it smells. Crocodiles in the Amazon Rain Forest
have higher reproduction rates than those in the Florida Everglades.
Red cars have a higher resale value than cars of other colors.
Dependent vs. Independent Variables Independent Variables—You control or
change; aka “manipulated” variable. Dependent Variable—You cannot control;
aka “responding” variable. Dependent Variable depends on the
independent variable. You measure the dependent variables
All other factors are held constant (not changed)
Identify the variables.1) The amount of cracking and peeling in paint was
measured at different temperatures.
2) Mice bite each other more frequently when they are crowded in the cage.
3) The number of letters recognized on an eye chart is determined by how far away the chart is.
4) Ropes of different diameters will hold different amounts of weight before breaking.
5) Lemon trees receiving the most water produce the largest lemons.
Data Table Construction
1. Organize important categories of information into columns.
2. Label columns using appropriate units.
3. Title should reflect contents of data table.
Collecting data
quaLitative data = color, texture, odor, etc. quaNtitative data = Numeric information
(49o F 6.8 grams 1,479,930,110 meters) Scientific notation is used to manage very
large or very small numbers.
Accuracy: how close a number is to what it should be.
Data points close together, but incorrect = high precision, low accuracy
Precision: degree of consistency or repeatability
Data points accurate, but widely ranging = high accuracy, low precision
Accuracy vs Precision
Organize data into graphs, tables.
Pie chart: Useful for
showing parts of a whole
Parts are labeled as % so whole circle = 100%.
Bar graphs Often used to
show how a quantity varies with factors such as time, location, or temperature
Relative heights of the bars show how the quantity varies
•What bushel price yielded the most income for the farmer?
Line Graphs The points on a
line graph represent the intersection of data for 2 variables:the independent andthe dependent variable
•Remember “DRY MIX”
•The Dependent (aka Responding) variable is on the Y axis.
•The Manipulated (aka Independent) variable is on the X axis.
Exponential Growth Curve