Scientific Method A world-wide system used to help solve problems or explain natural occurrences.

What is involved? I. Making observations II. Deciding on a problem or purpose to focus on III. Stating a hypothesis IV. Testing your hypothesis (experimenting) V. Collecting and organizing data ( using tables) VI. Analyzing relationships b/w data (using graphs) VII. Drawing conclusions VIII. Verifying the results

STEP 1: Make Your Observations Just think to yourself, “What types of things can be observed?” temperature, volume, mass, height, color, texture, taste, size, shape, movement … Remember - Observations are: the most important first step in science & continued throughout scientific studies.

Practicing Observations What types of things can you observe in the picture?

STEP 2: Deciding the Problem or Purpose Ask yourself, “What do I want to know about __________ based on my observations?” Write your Problem or Purpose: A As a statement or s a question

STEP 3: Making Your Hypothesis What is a hypothesis? A statement that gives a possible explanation to your problem. (-an educated guess at the solution or what the results will be) Your Hypothesis should be testable! It must be observable &/or measurable What is NOT testable with science? o opinions, politics, morals, social issues… T There must also be technology presentably available to prove it!

Is it a Hypothesis? Are the following testable? Why or why not? 1. Fish are happy when they swim. 2. Plants grow taller when fertilized. 3.It is wrong to hunt animals. 4.There is life in the next universe. 5.When a baby cries, he is hungry.

Writing the Hypothesis Common format (but not always necessary): Common format (but not always necessary): If…, then… You must clearly state both the: You must clearly state both the: WHAT you are going to test (independent variable) WHAT you are going to test (independent variable) WHAT you are going to measure (dependent variable). WHAT you are going to measure (dependent variable). NOTE: A hypothesis will state the cause and effect in the experiment, as well as a prediction of what your results will be.

Hypothesis Example EXAMPLE: Question: Would salt water effect the growth of my plant? Hypothesis: If I water my plant with salt water, then the plant’s growth will decrease. -OR- I think salt water will decrease the growth of my plant.

Practicing Writing Testable Hypotheses DIRECTIONS: Write a testable hypothesis for one problem given below: 1.Would adding soap to a bubble solution make more bubbles? 2.Do cooler temperatures affect how bacteria multiply? 3.Will acid rain have an effect on the grass in my yard?

STEP 4: Testing Your Hypothesis (Experimenting) All experiments contain many VARIABLES: Constant Variables controls (kept the same) Changing Variables independent vs. dependent Looking back at the hypothesis you wrote, circle the independent and underline the dependent variables.

1. controls: brand of soap, water temperature, agitation (swishing), water quality 1. controls: brand of soap, water temperature, agitation (swishing), water quality 2. controls: strain of bacteria, initial amount of bacteria, type and amount of food, environment other than temperature 2. controls: strain of bacteria, initial amount of bacteria, type and amount of food, environment other than temperature 3. controls: amount of water, type of grass, season, soil 3. controls: amount of water, type of grass, season, soil

There are 2 groups in your experiment: The control and the experimental groups. Both groups will have the same controls! Both groups will have the same controls! Only in the experimental group will one variable be changed from the control group. Only in the experimental group will one variable be changed from the control group. You CANNOT change or test more than one variable at a time! You wouldn’t know which variable caused something to happen! You CANNOT change or test more than one variable at a time! You wouldn’t know which variable caused something to happen!

STEP 5: Collecting Data Create a table of the data. Don’t forget to put units in the headings and add a specific title.

Analysis of Data Graphs provide visual comparison of data You must make inferences (logical connections) and predict trends (natural tendencies).

STEP 7: Drawing Conclusions Did your results agree with your hypothesis (Is it valid or supported)? Did your results agree with your hypothesis (Is it valid or supported)? We do not say “proven.” Include errors that may have been made. Include errors that may have been made.

STEP 8: Verify Results Experiments need to be repeated many times to limit the amount of error or bias. Experiments need to be repeated many times to limit the amount of error or bias. When results are consistent, THEORIES are created to explain a range of observations and findings. When results are consistent, THEORIES are created to explain a range of observations and findings. EX: Big Bang Theory, Theory of relativity (Einstein), Cell Theory, Theory of Evolution LAWS, however, are fixed statements of fact that do not explain the “why.” Describes a single action! LAWS, however, are fixed statements of fact that do not explain the “why.” Describes a single action! EX: Law of Gravity, Newton’s Laws

Hypothesis Becomes a Theory In short, a Hypothesis becomes a theory only when many scientists test the hypothesis and produce the same result. In short, a Hypothesis becomes a theory only when many scientists test the hypothesis and produce the same result. Once a theory is produced, it must also be falsifiable, which means it is capable of being modified based on new evidence. Once a theory is produced, it must also be falsifiable, which means it is capable of being modified based on new evidence.