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Scientific Method Notes, 9/9/14. Science is a Search for KNOWLEDGE that is based on EVIDENCE. Steps of a Scientific Method. 1. Gather Information . Make Observations using your 5 senses. Ask questions and define the problem . Observations make us ask questions about what we experience.
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Scientific Method Notes, 9/9/14 Science is a Search for KNOWLEDGE that is based on EVIDENCE
Steps of a Scientific Method 1. Gather Information. Make Observations using your 5 senses. • Ask questions and define the problem. Observations make us ask questions about what we experience. • Science uses evidence to answer testable questions.
3. Make a Hypothesis • Observations and questions lead to possible solutions. • A hypothesis is a possible explanation that is based on observation and seeks to answer the question. • A valid hypothesis is in the form of an if, then statement
3. Hypothesis Ex: “If the gene for glowing is inserted into a plant, then the plant will produce the glowing trait.”
4. Test the hypothesis (Experiment) • A controlled test of a hypothesis is called an experiment. • A valid experiment has two variables (things that change) and a control.
Variables • Any valid experiment has only two things that change - (The independent variable and dependent variable) • The independent variable is manipulated. It is the thing in the experiment that you directly change! • The dependent variable changes in response to the independent variable. It is the thing that you measure!
Constant Variables • Any valid experiment will only have two variables that change. All other things that could change MUST be kept the same. • Any unchanging variables are called constants or constant variables.
The Control Group • One test group (the control group) is not exposed to the tested effect (variable). • Another test group is exposed to the tested effect (variable). • Keep a control group for comparison.
Control and Variable • What happens when a fire fly gene (the variable) is added to tobacco genes? • This is the test plant.
Quick Write! • Describe an experiment to test the effectiveness of a fertilizer on tobacco plant growth. • Define the independent and dependent variables, your control group, and three constants.
5. Analyze Data • The measurements and observations made during the experiment are called data. • Data is evidence to support the hypothesis. Data must be measurablein someway. • Data cannot be an opinion or emotion.
5. Data Cont’… • Look at data for patterns and trends. • Graphs and charts make patterns more visible. • Use the numerical data to support your conclusions!
5. Data Cont’… • 3 Types of Graphs • Line graph is your data is continuous (ie. Time) • Bar if your data comes in categories • Circle if your data is part of a whole (fractions or %’s)
5. Data Cont’… • 3 Types of Graphs • Line graph if your data is continuous (ie. Time) • Bar if your data comes in categories • Circle if your data is part of a whole (fractions or %’s)
5. Data Cont’… • Parts of a graph • Title (Effect of IV on DV) • Independent Variable (X-Axis) • Dependent Variable (Y-Axis) • Axes labeled with units
6. Form Conclusions • Conclusions are only valid if data supports it. • Reject the hypothesis if the data does not support the hypothesis.
Conclusions cont’... • Error Analysis is part of conclusions. • List only KNOWN errors in the measurements • DO NOT list your guesses (e.g. “We might have....).
Theory • When many hypotheses have a large body of data and support they are unified into a Theory.