What is Science? (4)
The Scientific Method
You have read that science is divided into branches based on the type of matter being
studied: life science to study living matter, earth science to study earth-related matter
and physical science to study energy-related matter. You have read that the goal of
science is to understand the world and the mysteries surrounding these different types
of matter. You have read that when you make observations and ask yourself questions
about these mysteries, you are thinking like a scientist. And you have also read that when
you want to find an answer to a question, you must focus your question.
So you have already read a lot about 'what science is,' and now you will read about 'how science
is done.' How is science so different then, from history, where historians ask questions about what
went on in our past, or literature, where literary experts ask questions about the symbolism in a story
or its message, or even mathematicians who ask questions about patterns and relationships between
numbers. Basically, all subjects ask some type of question and all people ask questions about things at
one time or another. So what makes science so different from everything else?
Science is different because of the way scientists look for the answers to their questions.
Scientists use a problem solving approach different from mathematicians or historians. Scientists try
to find answers to their questions by using an orderly approach with specific steps called the
scientific method. The basic steps to the scientific method are:

Ask a question about an observation

Gather information or think about what you already know about your observation

Use that information to form a proposal called a hypothesis

Set up and complete an experiment to test your hypothesis

Record your results

Analyze your results and discuss them in a summary of your work

State a conclusion where you accept or reject your hypothesis and give reasons
why
Although you will learn these steps and follow them in order for a while, you will soon start to
see that the steps can overlap. In addition, if you are doing an experiment in the laboratory, you will
be able to follow these steps easily, but when you are doing an experiment or observing something
outside the laboratory, you may have to modify your steps or do them in a different order. In fact,
you must always remember that the scientific method is your guide, but the type of matter you are
studying (living, earth, or energy) and where you are performing your experiment (inside a lab or
outside a lab) will determine the exact procedure and influence your data and results. Here is an
example of an experiment that was conducted inside a lab that will help you begin to understand this a
little better.
Asking a Question About an Observation
Bundled up in warm clothes, heads bent into the wind, two friends walked along the beach.
Drifts of snow rose against the slats of a fence that in the summer held back dunes of sand. Beyond
the fence, a row of beach houses drew the attention of the friends.
There, from the roofs of the houses, hung glistening strips of ice. Only
yesterday these beautiful icicles had been a mass of melting snow dripping off the
edges of the roof. Throughout the night, the melted snow had continued to drip,
freezing into lovely shapes. The fact that the melting snow had frozen made sense to the
two friends. Just that morning on the news, the weatherman had stated that the
temperature would only be 32o F. The two friends already knew from experience that
32o F was the temperature at which water freezes.
The friends continued walking along the beach. As they came near the ocean's edge, the
friends spied a small pool of sea water. Surprisingly, it was not frozen as the icicles on the roofs had
been. What could be the reason for this, the friends wondered?
Without realizing it, the friends had taken an important step in the scientific
method: they had made an observation, recognized a problem between the pool of sea
water and the water frozen into icicles, and had asked themselves a question. The
friends decided to find out. They decided to think and act like scientists. A more
focused, scientific way to ask this question was, "Why doesn't sea water freeze
when the temperature is cold enough to freeze fresh water?"
Gathering Information About Your Observation
One thing a scientist would do after asking themselves that question is
gather information. Sometimes, we already know certain things about our
observation, such as how the two friends already knew what temperature water
would freeze. But often, we must gather information by looking around the area
where the observation is and then do a bit of research. This allows us to get
enough information to form our hypothesis.
For instance, by looking around the area, the two friends noticed that the sea water was
pooled on top of sand while the fresh water had been dripping off of roof tiles made from something
called tar as it froze. Through some research, they discovered that sand was made up of tiny pieces
of rock and minerals and tar was made from the resin of pine trees. Moreover, the two friends
already knew that sea water was salty and fresh water from melted snow was not. In fact, research
showed them that for each 2.2 pounds of sea water, there was about 1.2 ounces of salt dissolved in it.
Additionally, the friends noticed that when the tide came in from the ocean, the sea water was
covered up with several inches of new water that directly cut off the pool from the cold air, while the
fresh water from the roof was exposed to the air 24 hours a day. Through their research, they
discovered that the tide came in like this twice a day!
Forming a Hypothesis
A scientist will think about all of this information. He or she will begin organizing it in their
brain and wondering about different reasons why the fresh water froze while the sea water remained
unfrozen. Finally, the scientist will propose a possible solution to his or her question. This proposal is
called a hypothesis. One such hypothesis the friends might use could be based on the fact that fresh
water does not contain salt and sea water does. This hypothesis might look like this: If water
contains salt, then it will take longer to freeze than water without salt because salt slows down the
process of freezing. Another hypothesis the friends might use could be based on the fact that the
sea water was on sand and might look like this: If I freeze water on top of sand, then it will take
longer to freeze than water on a tar-roof, because the materials in sand slow down the process of
freezing. Regardless, it is important to remember that a good hypothesis always follows the same
format of: If...then...because.
Setting up and Completing an Experiment to Test Your Hypothesis
A scientist doesn't just stop with the hypothesis. Instead, he or she designs an experiment to
test the hypothesis. In a laboratory, such testing is usually done as an experiment. In good science
experiments, testing has to follow certain rules. For the hypothesis, "If water contains salt, then it
will take longer to freeze than water without salt because salt slows down the process of freezing," a
scientist would have to set up an experiment that ruled out every factor but salt as the cause for the
difference in freezing.
Let's see how the two friends, acting like scientists, would actually do this. First, they would
put equal amounts of fresh water into two identical containers. Then the scientist would add salt in
the same ratio as seawater (1.2 ounces of salt to each 2.2 pounds of water) to just one of the
containers. The salt would be a type of variable called a manipulated
variable. The reason is that the water has been manipulated, or changed, by
adding salt to it. It is also what is being tested. The water is another type of
variable. It is what the friends will measure. The water will either respond,
or not respond, to having salt added to it by freezing or not freezing sooner
than water without salt. The water is called a responding variable. Both
containers will be placed inside a freezer to test the hypothesis that salt
slows down freezing in water.
To eliminate the possibility of a hidden variable, a scientist would also run a control
experiment. A control is set up exactly like the first experiment, only without the manipulated
variable, in other words, without the salt. This control will have the same type and size containers
with the same type and amount of fresh water in them, and they will be placed in the same freezer, in
the same position, at the same temperature as the experiment. Data will also be collected exactly the
same way on the control as the experiment.
Additionally, scientists follow a few more rules to make sure there are no accidents. They
repeat the experiment AT LEAST three or more times. Furthermore, they write down every material
they use, every step of their experiment (including a drawing or photographs of what the experiment
looks like), and all their observations and measurement results. They do this so that any other person
wanting to repeat their experiment can do so step-by-step and so that other scientists can learn from
their experiment.
Recording and Analyzing Data
To determine if salt really does affect the freezing temperature of water, a scientist would
have to make careful observations and measurements of the experiment. The observations the two
friends would make include looking at the containers to see when the water began to freeze. This type
of observation, an observation made by using your sense of sight, smell, touch, taste, or sound, is
called qualitative data. In other words, you are observing a quality. A scientist would also have to take
measurements of the water as it cools down with a thermometer. This type of observation, an
observation that involves numbers such as the temperature, is called quantitative data. In other
words, you are observing a quantity (amount) of something, such as the mass, density, weight,
temperature, length, height, depth, amount, time or any other type of data that involves numbers, or
quantities, hence the name quantitative data.
In this specific experiment, the data collected by the two friends would include the
quantitative measurements of time and temperature and the qualitative observations of when the
water begins to look and feel frozen. The temperature would be collected in degrees Celsius instead
of degrees Fahrenheit because science does not use the Fahrenheit system. The two friends would
choose a time interval, such as every five minutes, to check the temperature of the water and make a
visual observation of how frozen or not frozen the water is. They would record this data in an
organized fashion to make it easy to read, such as in a data table. The data table would include labels
to explain what type of data is being collected. In the table below, the labels help us see that this is
the experiment data, not the control data, and that it is the 1st trial, not the 2nd or 3rd. It also
helps us see that the time is being taken in minutes, not seconds or hours, and that the temperature
is being taken in degrees Celsius. Finally, a special note tells us that the asterisk sign (*) shows us at
what temperature the water actually freezes.
Experiment Trial 1 (note: * means liquid has frozen)
Time (in minutes)
Fresh Water
Temperature (in o C)
Frozen Water
Temperature (in o C)
0
25
5
20
10
15
15
10
20
5
25
0*
30
-10
25
20
15
10
5
0
-10*
The results from one experiment are not enough to reach a conclusion. To be certain, a
scientist must repeat the experiment the same way at least three times for the data to be
considered reliable. If this experiment were completed exactly the same three times, the two friends
would see that the temperature falls at the same rate in both containers each time and that the
fresh water freezes at 0o C every time, while the salt water does not freeze until it reaches -10o C,
or ten degrees Celsius below zero.
This is the point where a scientist writes a summary of the experiment and includes a graph to
help explain the data. The graph is a visual way to show the data table. All graphs are created from a
data table. It is often quicker and easier to make comparisons of results on a
graph than it is from a data table. There are many types of graphs that a scientist
can use, such as a bar graph, line graph or circle graph, and learning to choose the
right kind of graph is also an important skill of a scientist. In this particular
experiment, a line graph would be used as line graphs are the best when showing
changes over time, such as the temperatures of water and saltwater in a freezer taken every five
minutes. Circle graphs are often used to show percentages or parts of a whole. Bar graphs are best to
use to show comparisons or frequencies, like 'how much' of something or answers to a survey.
Drawing a Conclusion
If the two friends had followed this procedure, and then repeated it at least two or more
times with the same results, they would be ready to draw a conclusion. Their conclusion would be that
salt does indeed slow down the freezing process of water. A scientist would write this conclusion
purposefully, also following these rules:
1. Accept or reject your hypothesis
2.
include a reason why, such as a summary of your data results
(like the freezing temperature of the water with salt and
without salt)
3. discuss errors, if any, you might have had or what you might do
differently next time
4. and include any new questions you have now that your experiment is
complete.
These new questions, or question, that you form after your conclusion are often like the
beginning of a new puzzle because it often happens in science that the solution of one problem
leads to yet another observation or question to answer. Thus the cycle of discovery goes on
and on. For instance, the two friends might still wonder if sand or tar have an effect on the
freezing rate of water.
Other Scientist Learning From Each Other
Just as the two friends needed to repeat their experiment three or more times to make sure
their results were reliable, other scientists need to be able to repeat their experiment as well. This is
why it is so important for anyone performing an experiment to record the question, information
gathered, hypothesis, materials, steps, data, summary and conclusion in an extremely detailed report
called a lab report. Once other scientists repeat an experiment from another's lab report many, many
times with the same results, it becomes a theory. After becoming a theory and being repeated many,
many times again by scientists worldwide, the results will finally be considered a law.
What is Science (4) Questions
Answer the following questions on lined notebook paper. Number each answer. Do not write on
this paper. If you are accessing this paper through SWIFT, you may copy/paste the questions
and then type your answers directly onto a word document.
1. An orderly approach with specific steps to problem solving is called what?
2. Data collected that is made from observations using the five senses (touch, taste, smell, hear, see)
is called ___________________ data.
3. Data collected this is made from measuring tools or using numbers is called _____________ data.
4. List the basic steps of the scientific method.
5. What format should a hypothesis always be in? ______...______...______
6. In an experiment, the variable that has been changed is called what?
7. In an experiment, the variable that is being measured is called what?
8. How many times should a scientist repeat his or her experiment to make sure the results are
reliable?
9. What does a scientist record his or her data in to keep it organized and easy to read?
10. When a scientist analyzes the data table and begins to write a summary of the results, he or she
should include a _________ as an easier and more visual way to show the data from the table.
11. List the information that should be included in a conclusion.
12. Why is it important for a scientist to write down every step of his or her experiment from the
original question about an observation at the beginning all the way to the conclusion at the very end?
13. What is this report called when a scientist writes down all the steps of an experiment?
14. Explain the difference between a theory and a law.