Steps of the Scientific Method

The Scientific Method involves a series of steps that are used to investigate a natural occurrence.

Observation before Experiment/Research Formulate a Hypothesis Scientific Method Problem Statement Observation before Experiment/Research Formulate a Hypothesis Experiment Observation Conclusion

Steps of the Scientific Method Problem Statement /Question: Uses critical thinking Look at facts/Research Looks for patterns

Steps of the Scientific Method 2. Research/Observation before Experiment: BE OBJECTIVE! Find out facts Look for patterns

Observation vs. Inference What do you think these words mean? Observations- Inferences-

Observation vs Inference

Observations? Inferences?

Observations? Inferences?

Observations? Inferences?

Let’s see if you’ve got it… Inference vs. Observation worksheet O I

Do you remember the next step?

Steps of the Scientific Method 3. Formulate a Hypothesis: “an educated guess” Predict a possible answer to the problem or question Testable prediction Explains how/why something works/occurs Example: If soil temperatures rise, then plant growth will increase.

Identifying a hypothesis B A C

Steps of the Scientific Method 4. Experiment: An organized procedure for testing a hypothesis. Include a detailed materials list. Step by step procedure

The procedure has TWO specified “groups”

Before we begin explaining- let’s get our brains ready Before we begin explaining- let’s get our brains ready. What do these words mean? Controlled Experimental Variable Constant Dependent Independent

Variables: What can “Vary” There are two kinds of variables Experimental Variable: The variable you are testing Ex- the fertilizer Controlled Variables (aka- Constants) All the things you will keep the same for everyone in the experiment Ex- how much you water the plants, how much sunlight they get…

Why do you need Constants/Controlled Variables? Controlled Variables: (CONSTANTS) -you must control any other variables that may affect your results Ex- if you are testing a fertilizer, you must keep the temp, precip, acidity of soil, etc. constant

Control Group Standard for comparison Does NOT contain the VARIABLE To compare the results of your variable group Does NOT contain the VARIABLE What you are testing Contains all the CONSTANTS What you are keeping the same Shows that your results are related to the condition being tested. To make sure your results are actually because of your variable

Experimental (Test) Group The group where you actually test the effect of your variable. Contains the experimental variable Remember: Variables are things that can CHANGE (vary) in an experiment There are two variables in every experiment…

Independent Variable The independent, or manipulated variable, is a factor that’s intentionally varied by the experimenter. Plotted on the X axis of a graph “Causes” your results

Dependent Variable Plot on the Y axis of a graph Is your results A. Depends on (will change because of) your independent variable Plot on the Y axis of a graph Is your results

Example If plant growth and fertilizer are related, then when given fertilizer, plants will grow taller. What is the INDEPENDENT VARIABLE? fertilizer What is the DEPENDENT VARIABLE? Plant growth

Hypotheses relate to the variables… The hypothesis is an educated guess about the cause and effect relationship between the independent and dependent variables. -The effect of the INDEPENDENT VARIABLE on the DEPENDENT VARIABLE

A good Experimental Set up Can only test ONE variable (per experimental group) Keeps all controlled variables constant between the groups

Steps of the Scientific Method 5. Observation: Results of the experiment Recorded as data tables, charts, graphs Two kinds…

Kinds of data Quantitative Data: Can be measured. Usually includes a number. Ex: 6 feet tall, 20 cm long “Quantity” Qualitative Data: Descriptions that can be observed but not measured Ex: purple, smelly, sharp “Quality”

Do not make assumptions, interpretations or opinions! Observations cont Do not make assumptions, interpretations or opinions! Should record on what you actually see or measure, etc!

Steps of the Scientific Method 6. Conclusion: contains 3 items Include a statement that accepts or rejects the hypothesis. Summary of experimental results Make recommendations for further study and possible improvements to the procedure.

Hierarchy of Scientific Ideas Problem Statement Hypothesis Theory Scientific Law What is the difference? How does each relate to the one below it?

Problem Statement and Hypothesis The problem statement is made before you really figure out how to test it. Often contains a question or words like “I wonder” ex “Why is the sky blue?” The hypothesis is a prediction that is testable and often stated in “if…then” statements.

Theory and Law A theory is a hypothesis which has survived repeated testing. It tells you “why or how” A scientific law is a “rule of nature”. It is often proven mathematically and cannot be disproven. tells you “what” Theories can be changed, laws cannot! Theories can serve to explain laws Ex- this ball will fall with an acceleration of 9.8 m/s2 is the law of acceleration due to gravity. If you want to know why the ball falls, you would use a theory.