NAME _______________________________________________ DATE ____________ BLOCK ____ INTRODUCTORY PACKET - Chemistry 1 SCIENTIFIC METHOD I. Scientific Method A. A logical approach to the solution of scientific problems B. A series of logical steps to follow in order to solve problems or answer questions (critical thinking: applying logic and reason to observations and conclusions) C. Begins with an observation (using your senses to obtain information directly) that indicates a problems or raises a question D. Steps: 1. Identify/state the problem; ask a question 2. Research: gather (background) information 3. Formulate a hypothesis a. an educated guess: possible solution to the problem or answer to the question b. an hypothesis can never be proved true beyond all doubt c. hypothesizing: process of forming testable statements about observable phenomena; predicting: stating in advance the result that will be obtained from testing a hypothesis 4. Experiment to test hypothesis a. experimenting: process of testing a hypothesis or prediction by carrying out data- gathering procedures under controlled conditions (conditions that eliminate extraneous influences and allow close observations to be made) b. a controlled experiment is based on a comparison of a control group/phase with an experimental group/phase; the control group and the experimental group are designed to be identical except for one factor: the experimental factor a/k/a independent variable a/k/a manipulated variable (the “cause”) c. dependent variable: the factor measured or observed in both the control and experimental groups; a/k/a the responding variable (the “effect”) d. Collect data: gather and record specific information based on observations (observing: use of one or more of the five senses to perceive objects or events) (i) quantitative data: measured quantities/amounts; measuring: process of determining the dimensions of an object, the number of objects in a group, the duration of an event, or other characteristics in precise units (ii) qualitative data: information that uses modifying terms (adjectives and adverbs), such as, “bubbles formed,” “the liquid turned blue,” “the solution felt warmer,” “it smelled sour.” e. sampling: technique of using a small part to represent an entire population 5. Organize and analyze data a. organizing data: (involves) placing observations and measurements in some kind of logical order, such as a graph, chart, table, or map b. classifying: process of grouping objects, organisms, or phenomena into an established organizational scheme, or developing new organizational schemes c. analyzing data: process of determining whether data are reliable and whether they support or refute a given prediction or hypothesis; using statistics, interpreting graphs, determining relationships between variables, comparing the data to those obtained from other studies, and determining possible sources of experimental error
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NAME _______________________________________________ DATE ____________ BLOCK ____
INTRODUCTORY PACKET - Chemistry
1
SCIENTIFIC METHOD
I. Scientific Method
A. A logical approach to the solution of scientific problems
B. A series of logical steps to follow in order to solve problems or answer questions
(critical thinking: applying logic and reason to observations and conclusions)
C. Begins with an observation (using your senses to obtain information directly) that
indicates a problems or raises a question
D. Steps:
1. Identify/state the problem; ask a question
2. Research: gather (background) information
3. Formulate a hypothesis
a. an educated guess: possible solution to the problem or answer to the question
b. an hypothesis can never be proved true beyond all doubt
c. hypothesizing: process of forming testable statements about observable phenomena;
predicting: stating in advance the result that will be obtained from testing a hypothesis
4. Experiment to test hypothesis
a. experimenting: process of testing a hypothesis or prediction by carrying out data-
gathering procedures under controlled conditions (conditions that eliminate extraneous
influences and allow close observations to be made)
b. a controlled experiment is based on a comparison of a control group/phase with an
experimental group/phase; the control group and the experimental group are designed
to be identical except for one factor: the experimental factor a/k/a independent variable
a/k/a manipulated variable (the “cause”)
c. dependent variable: the factor measured or observed in both the control and
experimental groups; a/k/a the responding variable (the “effect”)
d. Collect data: gather and record specific information based on observations (observing:
use of one or more of the five senses to perceive objects or events)
(i) quantitative data: measured quantities/amounts; measuring: process of
determining the dimensions of an object, the number of objects in a group, the
duration of an event, or other characteristics in precise units
(ii) qualitative data: information that uses modifying terms (adjectives and adverbs),
such as, “bubbles formed,” “the liquid turned blue,” “the solution felt warmer,” “it
smelled sour.”
e. sampling: technique of using a small part to represent an entire population
5. Organize and analyze data
a. organizing data: (involves) placing observations and measurements in some kind of
logical order, such as a graph, chart, table, or map
b. classifying: process of grouping objects, organisms, or phenomena into an established
organizational scheme, or developing new organizational schemes
c. analyzing data: process of determining whether data are reliable and whether they
support or refute a given prediction or hypothesis; using statistics, interpreting graphs,
determining relationships between variables, comparing the data to those obtained from
other studies, and determining possible sources of experimental error
NAME _______________________________________________ DATE ____________ BLOCK ____
INTRODUCTORY PACKET - Chemistry
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6. Formulate conclusion/s
a. inferring: process of drawing conclusions on the basis of facts or premises
instead of direct perception
(i) facts might include data gathered in a field study or an experiment
(ii) premises might include conclusions drawn from previous knowledge or
from a past experience
b. modeling: involves constructing a representation of an object, a system, or a
process that helps show relationships between data; may be visual, verbal, or
mathematical
7. Communicate: share information with other scientists through notes, collections,
presenting, publishing, conferencing
II. Scientific theory
A. A broad and extensively tested explanation of why experiments give certain results; provides a
general explanation for the observations made by many scientists working in different areas of
research over a long period of time
1. a tested (repeatedly) possible explanation of a natural event
2. most probable explanation for a set of data, based on available evidence
3. validity: similar to reliability; must "pass" these tests:
a. must explain observations simply and clearly
b. experiments supporting theory must be repeatable
c. must be able to make predictions from the theory
B. Scientific theories are always changing and can never be proved because
new information or experiments might disprove it; however, a thoroughly
tested theory seldom has to be thrown out completely. Instead they are
usually modified
C. Scientific theories unify many pieces of information to produce a grand design
D. Useful in helping to understand the unseen
E. Help make predictions
F. Scientific theories and laws have to be changed or replaced as new discoveries are
made
III. Scientific law
A. A concise statement that summarizes the results of many observations and experiments
over time; a statement of fact without explanation
B. States a repeated observation about nature without explaining it
C. a summary of an observed natural event
D. May be
1. A qualitative statement: expressed in words
2. A quantitative statement: stated mathematically
F. Scientific theories and laws have to be changed or replaced as new discoveries are
made
NAME _______________________________________________ DATE ____________ BLOCK ____
INTRODUCTORY PACKET - Chemistry
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IV. Organizing Data
A. Line graphs are best for continuous changes like those (changes) that occur over time
1. the horizontal (x-) axis usually shows the independent variable (intervals chosen by the
experimenter; the factor that is manipulated)
2. the vertical (y-) axis usually shows the dependent variable (its value depends on what
happens in the experiment)
B. Bar graphs are useful when you want to compare data for several individual items or events; a
bar graph often makes clearer how large or how small the differences in individual values are
C. A pie chart is ideal for displaying data that are parts of a whole.
Important vocabulary terms are bold.
NAME _______________________________________________ DATE ____________ BLOCK ____
INTRODUCTORY PACKET - Chemistry
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There are seven steps to the scientific method. The sentences below describe a scientific experiment, but
the sequence of events is out of order. Sequence the events properly by listing the numbers of the
sentences in the correct order below: Then decide which step in the scientific method each sentence
describes. Write that step in the space next to the numbers.
1. The scientists reported their findings in several scientific journals.
2. The scientists thought that a certain artificial sweetener used in foods and soft drinks could be the
cause of changes in mood and sleep patterns in people who used those products frequently.
3. The amount of sweetener consumed by laboratory rats was carefully measured as was the amount
of a certain chemical in their brains. This chemical seemed to control behavior in the rats and was
used as an indicator of mood. These data were entered into a computer.
4. Because human subjects are difficult to study, laboratory rats were used. One group of laboratory
rats was given the artificial sweetener and another group was not. All the rats were given identical
diet and living conditions.
5. When the results were analyzed, the scientists found that the experimental rats had three times the
amount of indicator chemical in their brains compared to the control rats.
6. Scientists at a leading university were concerned about a new artificial sweetener on the market.
Did this sweetener cause side effects such as changes in mood and other emotional problems in
the people who consumed them?
7. The scientists read about all the tests that had been done on the sweetener before it had come onto
the market.
MAKE SURE YOU READ THE NOTES (* AND **) ON THE BOTTOM!
Correct
Order* Steps in the Scientific Method**
* These numbers will be out of order.
** Simply list the steps of the scientific method here. Then match each up to one of the
numbered steps above.
NAME _______________________________________________ DATE ____________ BLOCK ____
INTRODUCTORY PACKET - Chemistry
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Read the following paragraph. Then complete statements 1-5 by writing the letter of the best answer in
the space to the left.
You are hired to investigate how a new medicine might affect the mass and sleeping time of those
taking the medicine. You obtain 100 rats of the same breed. One half are males and the other half are
females. You divide the rats into two groups each with the same number of males and females. Each rat
in Group A receives the same dose of medicine and is massed at the same time each day. Each rat in
Group B is massed at the same time as the rats in Group A, but does not receive any medicine. All rats
receive the same kind amount and kind of food. At the end of three months, you note that the rats that
received the medicine averaged 15 grams more mass and that the females receiving the medicine averaged
one-half hour more sleep each day than the rats that did not receive the medicine. You conclude that the
medicine may cause a gain in mass and may affect female sleep time differently than male sleep time.
___ 1. The purpose of the experiment was to determine
(A) if the medicine affects males and females differently
(B) the smallest effective dose of the medicine
(C) if the medicine changes the mass and sleeping time
_ 2. The control group of rats
(A) received the same dose of medicine as the experimental group of rats
(B) did not receive any medicine
(C) was allowed to eat as much as it wished
_ 3. The experimental group of rats was treated exactly like the control group
except
(A) for the amount of food given
(B) for the amount of medicine received
(C) for the number of males and females in the group
_ 4. The conclusion that the medicine may affect females differently than males
was based on
(A) sleeping time observations
(B) mass change observations
(C) comparing the amount of medicine given to males and females
_ 5. The standard of comparison for the experimental results was
(A) the control group of rats
(B) the experimental group of rats
(C) the experimental observations of mass change and sleeping time
NAME _______________________________________________ DATE ____________ BLOCK ____
INTRODUCTORY PACKET - Chemistry
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In an experiment, plants are given varying amounts of gibberellic acid and their heights are
measured weekly. Specifically, what are the independent and dependent variables?