OBSERVATION & INFERENCE

How can I use my senses & mind to gather data & make predictions?

OBSERVATIONS• Factual information

gathered with the 5 senses

• Not based on opinion

• Would not cause argument

TYPES OF OBSERVATIONS

• Qualitative: uses describing adjectives; describes the characteristics of something

• Quantitative: uses numbers; provides measurements of something

INFERENCES• Logical

assumptions based on observations

• Can be based on opinion

• Could be argued, but should not be nonsensical

INQUIR

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METHOD

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#1. SCIENTIFIC QUESTION

• Can be tested; the subject of the experiment

• A question that asks about the relationship between the independent variable and the dependent variable

• Ends with a question mark• Without pronouns (I, me, he, she,

etc.)• Recommended format: What is the

effect of ___________ on _________?

#2. HYPOTHESIS• The answer to the testable question; a

statement that predicts the results of the experiment

• A statement that predicts the relationship between the independent variable & dependent variable

• Ends with a period• Without pronouns (I, me, he, she, etc.)• Suggested format: If ___________________, then

___________________.

#3. EXPERIMENTAL DESIGNLet’s define each of these:

Independent Variable  

Control Group   Experimental Group  

Dependent Variable  Control/Constant Variables 1.

2.

3.

INDEPENDENT VARIABLE

• The variable the scientist changes, manipulates, or chooses

DEPENDENT VARIABLE

• The variable that responds to the independent variable

• The variable the scientist measures

CONSTANT/CONTROL VARIABLES

• All the things that scientist keeps the same to make sure the test is fair

CONTROL GROUP

• The group that is given the normal treatment

• A control group is not always present

EXPERIMENTAL GROUP

• The group(s) that is given the special treatment

Experiment: Bug Spray

Insect repellant (bug spray) is sprayed on one arm, and the other arm is not sprayed with any bug repellent. The number of bug

bites is recorded after 2 hours.

Independent variable? Dependent variable? Constant variables? Experimental group? Control group?

Experiment: Wheel Size

Let’s experiment to see how the size of a skateboard wheel affects the speed of the skateboard. We’ll use different size wheels and measured how fast the skateboard goes.

Independent variable? Dependent variable? Constant variables? Experimental group? Control group?

#3. EXPERIMENTAL DESIGN CONTINUED1. List of materials required

Organized Include quantities

2. Numbered, step-by-step directions/procedures

Each step begins with a present tense verb Without pronouns (I, me, he, she, etc.) Can be repeated exactly because all steps

have been made clear and nothing is skipped

#4. RESULTS

1. Organize collected data in a properly labeled data table Neat, titled, include units

2. Choose an appropriate graph for collected data Properly labeled graph (title, x, y, key,

scale)

3. Analyze the data Identify trends/correlation (positive,

negative, or no relationship) from data obtained in the experiment

#5. CONCLUSION (6 SENTENCES) • This experiment investigated … • The hypothesis stated …• According to the data, the hypothesis

was … (supported or not supported)• I know that the hypothesis was

supported/not supported because (use actual #) …

• Possible causes of error are …• The results of this experiment are

important because …