Transcript Observations - Living Environment @ GCHS

SCIENTIFIC INQUIRY
and SKILLS
What is science?
• a body of knowledge and a way of knowing
things
Scientific Inquiry
Scientific investigations involve the
following:
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questioning
observing
experimenting
collecting and organizing data
finding evidence and drawing conclusions
repeating the experiment several times
peer review
Observations and
Inferences
Observations
• An observation is the act of gathering
information.
• Observations are things or events that are
made using any of the senses or tools, such
as thermometer, graduated cylinders,
balances, or rulers.
Two types of Observations:
Qualitative data
• information that describes color, odor,
shape or some other physical characteristics
• in general, anything that relates to the five
senses
• how something looks, feels, sounds, tastes
or smells
Aim: How do we explain
characteristics of science?
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Do now: Brainstorming about the word
Science.
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Vocabulary: data, inferences,assumptions
opinions
Quantitative data
• numerical information such as temperature,
volume, pressure, time, the quantity of a
substance formed, or how much of a
substance is used up
• tells you how much, how little, how big,
how tall, or how fast
Inferences
• are conclusions or deductions based on
observations
• ideas or conclusions based on the results of
an experiment or observation
Assumptions
• An assumption is the belief that something
is true.
Opinions
• ideas people have that may or may not have
any basis in fact
• often biased
• influenced by an assumption that may or
may not be correct
How much have you learned?
1. When heavy rains occur while apple
orchards are in bloom, the apple crop the
following fall is much smaller than
normal. This information can best be
described as
A. an inference
B. a hypothesis
C. a prediction
D. an observation
2. A student prepared the following list of steps for
performing a laboratory investigation. She omitted
one important step for completing the
investigation. Using one or more complete
sentences, state the procedure that is missing in the
chart.
3. The following graph represents the results of an
investigation of the growth of three identical bacterial
cultures incubated at different temperatures.
Which inference can
be made from the graph?
A. Temperature is unrelated
to the reproductive rate
of bacteria.
B. Bacteria cannot grow
at a temperature of 5°C.
C. Life activities in bacteria
slow down at high temperatures.
D. Refrigeration will most likely slow the growth of these
bacteria.
4. Which of the steps listed below would be
first in a scientific investigation?
A. Perform the experiment.
B. Analyze the experimental data.
C. Formulate a hypothesis.
D. Define the problem to be investigated.
5. A student performed an experiment involving two strains
of microorganisms, strain A and strain B, cultured in
various temperatures for 24 hours. The results of this
experiment are shown in the following table.
Based on the results, the student inferred
that strain A was more resistant to
higher temperatures than B. What, if
anything, must the student do for this
inference to be considered a reasonable conclusion?
A. nothing, because this inference is a valid scientific fact
B. repeat this experiment several times and obtain similar
results
C. repeat this experiment several times using different
variables
D. develop a new hypothesis
The Scientific Method
• a systematic approach used in scientific
study
• an organized process used by scientists to
do research
• provides a method for scientists to verify
the work of others
The Scientific Method
Hypothesis
• a tentative explanation for what has been
observed
• a prediction based upon both research and
observation
“Experiments cannot prove a hypothesis”
A good hypothesis...
• predicts the relationship between cause and
effect in a way that can be tested
• can determine the organization of an
experiment
• can also help determine what data to collect
and how to interpret those data
• typically written as “if-then” or “I think
that”
Examples of Hypothesis Statements
• This hormone will make plants grow faster.
• If this hormone is applied to plant leaves,
then the plant will grow faster.
• I think this hormone when applied to plant
leaves will make the plant grow faster.
• The presence of this chemical in our
drinking water does not harm us.
• If this chemical is safe, then it will not
harm us when it is added to our drinking
water.
• I think the presence of chemical in our
drinking water does not harm us.
Designing an Experiment
What is an experiment?
• a set of controlled observations that test the
hypothesis
• a series of trials that are done to support or
refute (disprove) a hypothesis
• a set of controlled observations where the
results can be duplicated and rational
conclusions drawn
You suspect that applying the chemical
X to plant leaves will increase the growth
rate of the plant.
Hypothesis: If X is applied to the leaves of
plants, then the plants will grow more
rapidly than those that do not have X
applied to their leaves.
What is it that you will measure?
Variable
• changeable
• something that may or does vary or change
Two types of variables:
1. independent variable
2. dependent variable
Independent Variable
• the variable the investigation manipulates or
changes
Dependent Variable
• the value that changes in response to a
change in the independent variable
Controlling Variables
A control
• is a standard for comparison
• is an established reference point used as
standard for comparison
• allows one to make comparisons that
generate valid information
Experimental Controls
How much have you learned?
1. A new drug for the treatment of asthma is tested
on 100 people. The people are evenly divided into
two groups. One group is given the drug, and the
other group is given a glucose pill. The group that
is given the glucose pill serves as the
A. experimental group
B. limiting factor
C. control
D. indicator
2. A drug company tested a new medication
before putting it on the commercial market.
Pills without medication were given to 500
test subjects in group A, and pills with
medication were given to 500 subjects in
group B. In this experiment, the individuals
in group A served as the
A. host group
B. dependent variable
C. control
D. hypothesis
3. In order to find the percentage of organic matter in soil
from several locations, a student collected the samples,
weighed them immediately, roasted them for several
minutes in the flame of a Bunsen burner to burn off
organic matter, and weighed them again. The student
concluded that the difference between the first and second
weights represented the weight of the organic matter in the
soil. The most serious mistake that the student made in this
experiment was in
A. taking large samples
B. weighing the samples before roasting them
C. failing to dry the samples before first weighing them
D. assuming that roasting could remove the organic matter
4. In an investigation to determine the effects of
environmental pH on the germination of dandelion seeds,
25 dandelion seeds were added to each of five petri dishes.
Each dish contained a solution that differed from the others
only in its pH, as shown in the table. All other
environmental conditions were the same. The dishes were
covered and observed for 10 days.
Which is the
independent
variable?
Which is the
dependent
variable?
5. As part of a laboratory experiment, a thin
slice of peeled raw potato weighing 10
grams is placed in an oven at 80°C. After 5
hours, the potato sample is removed from
the oven and weighed again. The purpose of
this experiment might be
A. test for the presence of starch in living
tissues
B. isolate cells in various stages of cell
division
C. determine the water content of potato
tissue
D. study the rate of photosynthesis in
potatoes
THEORY
• an explanation that has been supported by
many, many experiments
• still subject to new experimental data and
can be modified
• lead to new conclusions
SCIENTIFIC LAW
• a relationship in nature supported by many
experiments
• a concise statement or mathematical
equation about a basic relationship or
regularity of nature
Scientific inquiry involves the
ability to use various methods of
• recording data
• representing data
• organizing data
Data can be organized into:
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Diagrams
tables
charts
graphs
equations
matrices
A diagram
A graph
A table/chart
A student was working on an
investigation to measure the relative activity
of an enzyme at various pH values. He
collected the following data: pH 2, enzyme
activity 10; pH 8, enzyme activity 50; pH
12, enzyme activity 10; pH 4, enzyme
activity 20; pH 6, enzyme activity 40; pH
10, enzyme activity 40
What is the independent variable in this
experiment?
Organize the given data by filling in the table below:
Construct a graph using the information in the table.
According to the data, this enzyme would
probably work best at what pH values?
A. 7 and 8
B. 2 and 12
C. 6 and 7
D. 4 and 10
Design an experiment
Designing an Experiment
How much have you learned?
1. Which laboratory procedure would be best for
demonstrating the effect of light intensity on the
production of chlorophyll in pea plants?
A. using 10 plants of different species, each
grown in the same intensity of light
B. using 10 plants of different species, each
grown in a different intensity of light
C. using 10 plants of the same species, each
grown in the same intensity of light
D. using 10 plants of the same species, each
grown in a different intensity of light
2. In an early trial of the Salk vaccine for polio,
1,830,000 school children participated. This
original trial was an attempt to determine whether
the Salk vaccine was effective in preventing polio.
Of the 1,830,000 children involved, only 440,000
received the vaccine. The remainder were not
given the vaccine because they
A. had a natural immunity
B. already had polio
C. served as control
D. were allergic to the vaccine
3. One ounce each of protein, carbohydrate, and fat are burned separately
in a calorimeter to determine the Caloric content. The results are
shown in the data table.
Which statement represents a valid conclusion based on the data?
A. An ounce of fat contains about twice as many Calories
as an ounce of protein.
B. Protein is a better energy food than carbohydrate.
C. Carbohydrates, fats, and proteins all yield
approximately the same number of Calories per unit of
weight.
D. Proteins and carbohydrates provide the most Calories
per ounce.
4. A scientific study showed that the depth at which
some microscopic plants were found in a lake
varied from day to day. On clear days, the plants
were found as far as 6 meters below the surface of
the water but were only 1 meter below the surface
on cloudy days. Which hypothesis would these
observations support?
A. Light intensity affects the growth of
microscopic plants.
B. Wind currents affect the growth of microscopic
plants.
C. Nitrogen concentration affects the growth of
microscopic plants.
D. Precipitation affects the growth of microscopic
plants.
5. Tomato plants in a garden are not growing
well. The gardener hypothesizes that the
soil is too acidic. To test this hypothesis
accurately, the gardener could do which of
the following?
A. Plant seeds of a different kind of plant.
B. Move the tomato plant to an area with
less sunlight.
C. Change the pH of the soil.
D. Reduce the amount of water available to
the plant.
6. A scientist tested a hypothesis that white-tailed deer would
prefer apples over corn as a primary food source. The
findings of the test, in which the scientist claimed that the
deer preferred apples, were published. Which research
technique, if used by the scientist, might result in this
claim being questioned?
A. The scientist observed four different locations
at various times.
B. The scientist observed a total of 500 deer in 20
different locations at various times.
C. The scientist observed 200 deer in various
natural settings, but none in captivity.
D. The scientist observed 300 deer in various
locations in captivity, but none in natural
settings.
7. The current knowledge concerning cells is
the result of the investigations and
observations of many scientists. The work
of these scientists forms a well-accepted
body of knowledge about cells. This body
of knowledge is an example of a
A. hypothesis
B. controlled experiment
C. theory
D. research plan
8. The data below summarizes the results of an investigation
in which seeds from the same plant were grown under
different conditions of temperature and relative humidity.
Which conclusion can be drawn from the information
in the data table?
A. Color in this species is determined by genes,
only.
B. Many characteristics are not inherited.
C. Mutations occur only when plants are grown at
low temperatures.
D. There is an interaction between environment
and heredity.
9. Diagrams, tables, and graphs are used by
scientist mainly to
A. design a research plan for an experiment
B. test a hypothesis
C. organize a data
D. predict the independent variable
10. Scientific studies have indicated that there is a
higher percentage of allergies in babies fed
formula containing cow’s milk than in breast-fed
babies. Which statement represents a valid
inference made from these studies?
A. Milk from cows causes allergic reactions in all
infants.
B. Breast feeding prevents all allergies from
occurring.
C. There is no relationship between drinking
cow’s milk and having allergies.
D. Breast milk most likely contains fewer
substances that trigger allergies.