The Scientific Method 1

Theory vs Hypothesis Theory- generalization that explains a body of known facts or phenomena Hypothesis- a testable prediction based on research and observations

3 The Scientific method is a systematic way of gathering evidence to support ideas and theories that help explain the natural world around us. The Scientific Method

Steps of the Scientific Method Step 1: State the Problem What are we trying to figure out? It is usually stated as a question containing words like “How”, “Why”, and “What” The problems that are investigated are found using observations 4

Steps of the Scientific Method Step 2: Research & Hypothesis A Hypothesis is a testable prediction based on research and observations. The hypothesis is the experimenter’s idea of what will happen. Before a hypothesis is formed, there must be prior research or observations taken to make a prediction about the problem. 5

Forming a Hypothesis When an experimenter has an idea of what will occur, they will write this idea as an “If... then…” statement. Examples: If I place a plant in sunlight, then it will grow better. If I eat a lot of Twinkies, then I will gain a lot of weight. A hypothesis MUST BE TESTABLE 6

Steps of the Scientific Method Step 3: The Experiment In order to test the hypothesis, an experiment must be conducted. Consists of a list of materials and the procedure (steps of the experiment) Experiments must be reproducible so other scientist can try them for themselves. There are four specific parts to an experiment. 7

Independent Variable (Mix) Independent Variable (Mix) Also called the controlled or manipulated variable What the experimenter controls during the experiment to test the hypothesis X axis Dependent Variable (Dry) Dependent Variable (Dry) Also called the measured or responding variable What you’re trying to find Y axis 8 The Parts of an Experiment

Constants Constants Everything else in the experiment besides the variables Held the same to make sure only the independent variable is affecting results Control Control A standard for comparison Usually a trial of the experiment where the independent variable is totally absent 9 The Parts of an Experiment

Steps of the Scientific Method Step 4: Data Analysis After the experiment has been conducted, data must be organized to make a conclusion Data should first be organized in a data table. Then, data can be visually organized using a graph in order to more easily form a conclusion 10

Precision vs Accuracy Accuracy- the condition or quality of being true, correct, or exact Precise- the extent to which a given set of measurements of the same sample agree with their mean

Qualitative vs Quantitative Qualitative- non-numerical system observations Color, smell Quantitative- numerical system observations Time, mass, volume

Steps of the Scientific Method Step 5: Making a Conclusion After the experiment has been completed, a conclusion must be formed. Every conclusion must give evidence for the new idea or outcome. It should contain the following: 1.Restatement of the Hypothesis 2.Brief description of lab organization 3.Comment on the data collected 4.Statement of the trend or pattern in the data collected 5.Statement discussing whether your hypothesis was accepted or rejected and what you can do further. 13

Read the first scenario and answer the next 4 questions. 14

What is the best hypothesis for the scenario? A.If Sandy uses more soil in a cup, then the plants will grow taller. B.If Sandy plants fewer seeds in a cup, then the plants will grow taller. C.If Sandy plants more seeds in a cup, then the plants will grow taller. D.If Sandy uses less soil in a cup, then the plants will grow taller. 15

What is the independent variable? A.Amount of soil B.Size of cup C.Number of seeds D.Height of plants 16

What is the dependent variable? A.Amount of soil B.Size of cup C.Number of seeds D.Height of plants 17

What is the constant? A.Amount of soil B.Size of cup C.Type of seeds D.Number of seeds 18

Read the second scenario and answer the next 5 questions. 19

What is the best hypothesis for the scenario? A.If more compost is used, then the plants will grow taller. B.If the plants receive more water, then the plants will grow taller. C.If the plants receive more sunlight, then the plants will grow taller. D.If the plants receive older compost, then the plants will grow taller. 20

What is the independent variable? A.Amount of water B.Age of compost C.Height of plants D.Amount of compost 21

What is the dependent variable? A.Amount of water B.Age of compost C.Height of plants D.Amount of compost 22

What is the constant? A.Amount of water B.Age of compost C.Amount of compost D.Height of plants 23

What is the control? A.The flat with 3 month old compost B.The flat with 6 month old compost C.The flat with no compost D.The flat that received no sunlight 24