Investigate and Experiment
Brown ant biting
a blade of grass
What Is
Science?
Science is a way of understanding the world
around us. Scientists often ask questions about what
they observe. They call on many skills to help them
answer these questions. This process of asking and
answering questions in science is called inquiry.
In this section you will see how scientists use
inquiry skills to learn about ants.
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Investigation and
Inquiry Skills
Experimentation
These are the inquiry
skills scientists use. You
can use these skills, too.
Observe
Infer
Classify
Measure
Use Numbers
Communicate
Predict
Record Data
Analyze Data
Form a Hypothesis
Use Variables
Experiment
Make a Model
6. Scientific progress is made by
asking meaningful questions
and conducting careful
investigations. As a basis for
understanding this concept
and addressing the content
in the other three strands,
students should develop their
own questions and perform
investigations. Students will:
a. Differentiate observation from
inference (interpretation) and
know scientists’ explanations
come partly from what they
observe and partly from
how they interpret their
observations.
b. Measure and estimate the
weight, length, or volume of
objects.
c. Formulate and justify
predictions based on causeand-effect relationships.
d. Conduct multiple trials
to test a prediction and
draw conclusions about
the relationships between
predictions and results.
e. Construct and interpret graphs
from measurements.
f. Follow a set of written
instructions for a scientific
investigation.
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Observation >
Are you an observant person? You might look
out the window to see if it is raining. You might
even listen for rain on the windowsill. You make
observations throughout your day. Observations
on the world around us often raise questions.
The diagram on this page shows processes that
scientists use to answer questions. Many call this
the “scientific method.” Scientists don’t always
use all of the steps. They may not use them in
the same order.
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Inquiry Skills
When you make
observations, you use
these skills.
Observe Use your
senses to learn about an
object or event.
Classify Place things
that share properties
together in groups.
Measure Find the size,
distance, time, volume,
area, mass, weight, or
temperature of an object
or an event.
Scientists are curious people who observe the world
around them and try to understand it. To observe means
to use your senses to learn about something. Scientists
ask questions about the things they observe. You can too.
When you ask questions about the things you see, smell,
hear, taste, or feel, you are a scientist.
What do you think the ants in this photo are doing?
Describe what you see.
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Question and Hypothesis >
Do you ask “why” questions when you are
curious about things? The work of scientists often
starts with an unanswered question. Scientists
then suggest a possible answer that can be tested
with an experiment. This is known as forming a
hypothesis. A good hypothesis must:
▸ be based on what you observe.
▸ be testable by doing an experiment.
▸ be useful in predicting new findings.
The photo shows the entrance to an ant nest in
the desert. Why do you think desert ants build
their nests deep underground? Form a hypothesis
to answer this question.
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Inquiry Skills
Scientists often do research before they
experiment. They look in books, scientific journals, or
Internet resources for information that other scientists
have found. Scientists also know that they cannot
rely on someone’s opinion or claim unless it has been
backed up by observations.
When you ask questions
and form hypotheses,
you use these skills.
Infer Form an
idea from facts or
observations.
Form a Hypothesis
Make a statement that
can be tested to answer
a question.
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Now it’s time to test your hypothesis with an
experiment. In experiments you change one
variable to see what happens with another variable.
For example, you might vary the type of soil in an
ant farm to see if it varies how many tunnels the
ants build. It is important to change only one
variable at a time. What would happen if you
changed both the type of soil and the type of
ant at the same time?
Experiments must be able to be repeated, too.
Scientists describe the steps of their experiments and explain their results to the
public. This allows other scientists
to repeat the experiment. It also
allows others to evaluate and
compare each other’s work.
They can check their own
work too! So a good
experiment must:
▸ change only one
variable at a time.
▸ be able to be
repeated.
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Experiment >
Inquiry Skills
Before you test a hypothesis, you must have a plan.
When scientists make a plan, they think about the
variables they want to test. A variable is something
that can be changed or controlled. It is important to
change or control only one variable at a time. Keep all
other parts of the experiment the same. That way you
will know what caused your results.
After they determine their variables, scientists
decide what materials they will need. Then they write
a procedure. A procedure is a series of numbered
steps that tell what to do first, next, and last.
After scientists have developed their procedure,
they predict what will happen when they follow it. To
predict means to tell what you think will happen.
When you experiment,
you use these skills.
Experiment Perform
a test to support or
disprove a hypothesis.
Use Variables Identify
things in an experiment
that can be changed or
controlled.
Predict State possible
results of an event or
experiment.
Make a Model Make
something to represent
an object or event.
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What’s one important part of a science
experiment? Collecting and recording good
data! When data are collected, they may then
be explained, or interpreted. Collecting and
interpreting data often requires working with
numbers. This scientist uses numbers to record
her observations.
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Collecting Data >
Inquiry Skills
When scientists follow their procedure, they make
observations and record data. Data is information.
Measurements are a type of data. Scientists use
measurements whenever they can to describe
objects and events. Scientists measure such things as
length, volume, mass, temperature, and time.
Scientists repeat their procedure several times.
This helps them know if their results are correct. They
often compare their results with other scientists.
Other scientists will repeat the procedure to see if
they get the same results.
When you collect and
interpret data, you use
these skills.
Use Numbers Order,
count, add, subtract,
multiply, and divide to
explain data.
Measure Find the size,
distance, time, volume,
area, mass, weight, or
temperature of an
object or an event.
Record Data
Accurately arrange
and store information
collected in science
investigations.
Analyze Data Use the
information that
has been gathered to
answer questions or
solve a problem.
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You’ve collected and interpreted data. Now what?
It is time to draw a conclusion. A conclusion states
whether your data support your hypothesis.
But what if your data do not support your
hypothesis? Perhaps different experiments are
needed. Perhaps a new question will result.
Scientists also share with others what they have
found. This allows scientists around the world to
stay informed. And it allows scientists to check each
others’ work.
Scientists also share what they have learned
with the public. Dr. Edward O. Wilson shares his
knowledge of ants and other insects through books
and lectures.
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Conclusion
Inquiry Skills
Scientists organize and analyze their data
to see if the results support or disprove their
hypothesis. They determine if their prediction
matched their results. They draw conclusions
and try to explain their results. When you draw
conclusions, you interpret observations to answer
questions.
When you draw
conclusions and
communicate results,
you use this skill.
Communicate Share
information.
Sometimes the results of an experiment lead
to new questions. These questions can be used
to form a new hypothesis and perform new tests.
The process starts all over again. This process
of asking and answering questions is called the
scientific method.
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Forming a Hypothesis
Most science experiments start with an unanswered question.
To design a good experiment you must keep a few important
details in mind. Here is a sample question that two students
wanted to explore. Take a good look at it. See if there is anything
about it you would change.
Question
• Would more ants be attracted to an unpeeled piece of fruit or to
a piece of fruit that was peeled?
The students turned the question into a statement they could
test. This statement is called a hypothesis. A hypothesis is an
“if... then...” statement. Here is the hypothesis proposed by
the students:
Hypothesis
• If fruit is peeled, then more ants will be attracted to it.
Can this hypothesis be tested?
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Defining Variables
The next step is to make a plan to test your hypothesis. The test
for your hypothesis is your experiment.
You need to decide what you are testing and what you are not
testing. These are your variables.
Controlled variables are not being tested. They are used to control
the experiment so it can be repeated.
In this experiment the controlled variables will be:
• the type and ripeness of the fruit .
• the place where the fruit is placed.
• the time of day you make your observations.
The only factor that will change is what you are testing. This is
the independent variable. The best experiments test one variable at
a time.
In this experiment the independent variable will be:
• whether the fruit is peeled or left unpeeled.
In an experiment, the factors you measure are called the
dependent variables. They change based on the independent
variable.
You will be counting the number of ants on the fruit. The
dependent variable in this experiment will be the number
of ants on the fruit.
What other variables can you identify?
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Designing an Experiment
Then design your experiment to test your hypothesis.
Here is one student’s design.
Procedure
1. Find a spot such as under a tree, where there will likely be ants.
2. Place one unpeeled banana and a peeled banana on the
ground one meter apart from each other.
3. Predict which piece of fruit ants will be more attracted to.
4. Leave both bananas on the ground. Check to see if there are
any ants on them. Check back after one hour; after two hours;
after three hours.
5. Make a data table like the one below. Fill in for each banana the
number of ants after one hour; after two hours; and after three
hours.
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6. Repeat the experiment on another day.
7. Did your results match your prediction?
8. Compare your results with other students’
results to confirm your findings.
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4 IE 6.f. Follow a set of written instructions
for a scientific investigation.
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Analyzing Data
To communicate your results, set up your data clearly.
The students used the data table to set up a line graph.
They grouped the numbers in their data table using the
scale: fewer than 10; 10–20; more than 20.
See the students’ results on the graph below.
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Explain how you think the line graph makes the results clear.
Once scientists have done an experiment, they repeat the
experiment. Why is this important?
4 IE 6.d. Conduct multiple trials to test a prediction and draw conclusions
about the relationship between predictions and results.
4 IE 6.e. Construct and interpret graphs from measurements.
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Forming New Questions
The exciting thing about doing experiments is that you
find out new things and may have new questions. After doing
their experiment, the students wrote down new
questions they wanted to study:
• What if you placed the fruit in another location?
• What if you used a different kind of fruit or food?
• What if you did the experiment during a different time of
day or a different season?
• What if you did the experiment in different weather?
Use one of the above questions or another one that you think
of. Set up a hypothesis and experimental plan to test it.
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