Chapter 1.3b Scientific Method - Beachwood High School 3b... · What are the steps of the scientific method? 1. Define the problem a. Select an event or phenomenon for ... Slide 5

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Chapter 1.3bScientific Method

Mrs. BaldessariBiology

Objective : Identify and

apply the steps of the

scientific method.

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–The goal of science is to:

• investigate and understand the natural world.

•explain events in the natural world.

•use those explanations to make useful predictions.

What is the goal of science?

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Thinking Like a ScientistScientific thinking begins with observation.

• Observation is the process of gathering information about events or processes in a careful, orderly way

• Use your senses to observe

– See, hear, touch, taste, smell, etc.

• Can also use tools to measure

– Temperature, length, volume, etc.1

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What are the steps of the scientific method?

1. Define the problema. Select an event or phenomenon for

investigation.

b. The problem is often based on some type of unexplainable observation.

c. The problem is usually stated as a question to be answered.

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What are the steps of the scientific method?

2. Gather relevant researcha. The researcher gathers useful information

from scientific literature.

b. Observations of the problem may also contribute to research.

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What are the steps of the scientific method?

3. Formulate a hypothesis• A hypothesis is an “educated guess” about the

answer to the problem.

• The hypothesis is based on information, which has been learned about the problem through research.

• May be stated as an “If…., then…” statement

• A hypothesis may be ruled out or confirmed.

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What are the steps of the scientific method?

4. Test the hypothesis• A hypothesis must be proposed in a way that can be

tested.

• Hypotheses are tested by performing controlled experiments or by gathering new data.

• Remember, controlled experiments are experiments that only have one variable that can change, all other factors are held constant

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What are the steps of the scientific method?

5. Record data and observations

• The information gathered from observations is called data.

•Quantitative data are expressed as numbers, obtained by counting or measuring.

•Qualitative data are descriptive and involve characteristics that can’t easily be measured.

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• Look around the room list Five Quantitative observations:

• 1.

• 2.

• 3.

• 4.

• 5.1

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• Look around the room list Five Qualitative observations:

• 1.

• 2.

• 3.

• 4.

• 5.

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Inferences

• Scientists use data to make inferences.

• An inference is a logical interpretation based on prior knowledge or experience.

• Is this an observation or inference?

• 1. Sam is smiling because he is happy

• 2. Sarah’s gold colored braces were removed today

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Observation vs inference

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Designing an Experiment with

TwinkiesDiscussion of independent

variables and control variables

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What is the

control?

What is the

independent

variable?

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Control

• Is an experimental set-up with all the parts of the experiment BUT NOT the one variable being tested

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What is the

independent

variable?

What might a

control be?

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What is the

independent

variable?

What might a

control be?

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Identify Variable

and the control:

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To get all the

air out, the

twinkie was

“liquified.”

So which side

is the control?

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What are the steps of the scientific method?

6. Draw conclusions• Researchers often work in teams to analyze, review, and

critique each other’s data and hypotheses.

• A review process helps ensure conclusions are valid.

• To be valid, a conclusion must be based on logical interpretation of reliable data.

• Always address sources of error…are your results legitimate?

• Theories and laws are heavily supported by experimental results

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Littell. All rights reserved.21

Figure1.1: The

various parts of

the scientific method.

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Science is an ongoing processthat involves:

–asking questions

–observing

–making inferences

–testing hypotheses

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State the Question

•“What is the effect of…”

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Hypothesis

• “If…then…” If I diligently wear my goggles in the lab, then I will not injure my eyes during Chemistry class this year.

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Experiment

• Independent Variable -what you change goes on the X-axis of the graph

Dependent Variable -what changes as a result of what you did – goes on the Y-axis of the graph

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Independent Variable?Dependent Variable?

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Experiment

• Constants-all the things in the experiment that stay the same

• In a Twinkie lab :

same brand of Twinkies

same flavor of Twinkies

same degree of freshness

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Experiment

• Control – the part of the experiment that does not have the independent variable in it

• In a Twinkie lab, it could be the room temperature

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Experiment

Record the datagraphs

charts

video

write observations

measurements

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Conclusion

• Agree or disagree with the hypothesis

• Goggles did protect my eyes during an accident

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Scientific method

Do background Research

Record Results

Analyze Results

Draw a conclusion

Present results

State your question or the problem

Formulate a hypothesis,identify variables

Design a Controlled Experiment, establish a procedure

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Science as a Way of Knowing

• Scientific understanding is always changing.

• Good scientists are skeptics who question both existing ideas and new hypotheses.

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1–1

Observations involving numbers are known as

a. qualitative observations.

b. hypothetical observations.

c. quantitative observations.

d. inferred observations.

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1–1

A scientist takes paint chips from 10 apartments in a large building. She tests for the presence of lead in the paint and finds it in all 10 samples. She then concludes that lead paint is probably present in all 120 apartments in the building. This conclusion is an example of

a. a scientific fact.

b. a scientific error.

c. proof.

d. a reasonable inference.

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1–1

A possible explanation for a set of observations

is known as

a. data.

b. a hypothesis.

c. an inference.

d. a result.

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1–1

A good scientific hypothesis must be

a. correct.

b. able to be tested.

c. obvious.

d. based on common sense.

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