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Processes and Procedures of Science

and Designing an Experiment

S8.A.1.1.1- 4

S8.A.2.1.2, 3

2

• Knowledge of the world around us gained by observing, experimenting, and thinking

• A scientist observes and questions natural occurrences.

Science

3

Hypothesis:• A testable prediction

•Scientists use prior knowledge, new information, and observations to form a hypothesis

• An experiment is a test used to test a hypothesis

Hydrochloric Acid will react with Aluminum foil

Let’s try it!

4

Scientific Method

1. State the problem (question)

2. Gather information3. Form a hypothesis4. Test a hypothesis

(experiment)5. Record and Analyze data6. State a Conclusion7. Repeat work8. Communicate your work

5

Scientific Theory

Scientific theory- an explanation that is supported by data and observations, not an opinion

**Theory (everyday use) – guess or opinion

•If new observations and data do not agree with an accepted theory, scientists change theories or develop a new theory that explains all observations

•This happens constantly in Astronomy

•Example- Geocentric and Heliocentric Theory

6

Scientific Experiment

• All conditions are kept the same (Constants) except for one.

• The one that changes is the independent variable

• Dependent variable what is being observed or measured during or at the end of the experiment

• The data you collect describes the dependent variable

• Control Group – exposed to normal conditions. Used for comparison. Not all experiments have one

7

Experiment Design

• Well planned experiments have 3 variables:

1. Constants

2. Independent Variable

3. Dependent Variable

Which Color Light will a plant grow tallest under?

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Constants

• Constants answer the question "What do I keep the same?“

• All other conditions or variables in an experiment that must remain the same

1. Type of plant

2. Soil type and amount

3. Feeding and watering schedule

4. Wattage of bulbs

5. Time under light

6. Temp and humidity of chambers

7. Size of chamber

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Independent Variable

• Independent variables answer the question "What do I change?“

• The ONE thing that the scientist changes

• The “cause”

Color of Light

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Dependent Variable• Dependent variables answer the question "What

do I observe?“• Is the thing being measured or observed during

or at the end of the experiment.• What you are collecting data for• It depends on the independent variable

Plant height

depends on the color of light

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Treat with antibiotic “A” Treat with antibiotic “B” Treat with no antibiotic

bacteria

Independent Variable-

Dependent Variable-

Constants-

Control Group

Control group:

•A sample in the experiment that is not being tested

•Used for comparison purposes but not all experiments have one

Type of antibiotic

Bacteria Growth

Type of bacteria, amount of bacteria, amount of antibiotic, petri dish, atmospheric conditions, lighting, work time

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Which Type of Fertilizer makes a Tomato Plant Grow Tallest?

Fertilizer A

Fertilizer B

Control Group- No Fertilizer

Independent Variable- Type of Fertilizer

Dependent variable- Plant Height (the data you will be collecting)

Constants- pot type, plant type, soil, watering, sunlight,