# Scientific Concepts Assignment 1 3

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Scientific Concepts
Big Idea: The scientific method is a systematic approach to answering questions about the world we live in. Laws,
hypotheses, and theories are scientific statements about the phenomena we observe.
1. Recall an example of how
you used the scientific
method to solve a problem
this past week.
The Scientific Method
Researchers use the scientific method
to answer questions and explore ways
to solve problems. The scientific
method was established to prove
hypotheses
via
observations,
measurements, and experimentation. It
has since been used as a guide for
scientists in their quest for knowledge.
Although sometimes condensed or
broken into more parts, the scientific
method consists of steps organized in a
logical manner. This makes it easier to
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Figure 1: The scientific method.
Step 1: Make an observation and ask a question.
Step 2: Gather background information and form a hypothesis
Step 3: Perform an experiment and collect data. Repeat the
experiment to verify the data.
Step 4: Analyze the data.
Step 5: Conclude whether to accept or reject the hypothesis.
If rejected, go back to step 2.
Step 6: Share the information with others.
Even if you are not a scientist, you use many of these steps to solve
everyday problems of your own. For example, if you observed that your
TV remote stopped working, you would likely hypothesize that the
the batteries and checking if the remote worked. If it didn’t, you would
reject your hypothesis and try something different. In this way, you’ve
used the scientific method without even thinking about it.
2. Explain what we learn from a
hypothesis that has been
rejected.
3. Imagine you are a chef
working on a new recipe.
What would occur during the
experiment and result phase?
Did you know?
4. Identify two characteristics
of a good hypothesis.
The scientific method is not attributed to any one person. Instead, it grew
from the methods of multiple well-known scientists dating back to the 4th
century B.C. From Aristotle, to Francis Bacon, to Galileo, to Isaac Newton,
the scientific method has evolved over time.
Law, Hypothesis, and Theory
There are three main types of scientific statements that are classified
by the information they explain.
A hypothesis is a possible explanation for an observation. A valid
hypothesis must be testable. If the evidence collected does not support
the hypothesis, it can be rejected, and a new hypothesis can be formed.
Most hypotheses are written as “If…then…” statements. They are
sometimes referred to as “educated guesses,” but a hypothesis is never
uninformed. Rather, scientists rely on prior knowledge to form a
hypothesis.
5. Hypothesize how placing a
plant under only green light
might affect its growth.
Bad hypothesis: Smoking causes lung cancer.
Good hypothesis: If smoking causes lung cancer, then people who
smoke will have a higher rate of developing lung cancer than those who
do not.
Good hypothesis: People who smoke will have a higher rate of
developing lung cancer.
Scientific laws are statements about observations of phenomena under
certain conditions. Laws tell us what happens, but do not explain why
it happens. Scientific laws are accepted as truth because they are
observed to always work. Most scientific laws are mathematical
equations. Some examples include the Law of Gravity, Boyle’s Gas
Laws, and the Law of Conservation of Energy.
A scientific theory is a well-substantiated explanation that includes
related facts, laws, and verified hypotheses. Theories must be able to
explain past events and predict new observations. They are supported
by data and evidence. Over time, theories evolve and can be replaced
as new evidence is acquired. In general, theories are backed by enough
information that scientists consider them correct and highly reliable.
Some examples of famous theories include the Theory of Evolution, the
Cell Theory, and Atomic Theory.
6. Identify the main difference
between a scientific theory
and law.
The Experimental Process
When designing an experiment to test a hypothesis, scientists use an
independent and dependent variable. The independent variable is
what is changed or controlled during the experiment. The dependent
variable is what is being tested and measured. As the independent
variable is changed, the effects on the dependent variable are
measured and recorded. A good hypothesis will state both the
independent and dependent variables. Look at the following
experiment:
7. Create a hypothesis and
underline the independent
variable.
8. Determine from the
following hypothesis the
dependent and independent
variables.
If you drink coffee before bed,
then it will take more time to fall
asleep.
Good experiments have both an experimental and control group. An
experimental group receives the independent variable, while a control
group does not. In the end, the two groups are compared to determine
if there is a difference. It is important to note that both the control and
experimental group should be similar in all other aspects. This ensures
that only the independent variable can make the difference.
The data that is collected during an experiment can be qualitative or
quantitative. Qualitative data is not a numerical measurement.
Instead, it is a description. By contrast, quantitative data is a quantity
or measurement. For example, if the height of a plant is described as
“tall,” it is qualitative data. If instead the height is measured as 15.5
inches, then it is quantitative data.
Qualitative
It smells like cherries.
The color is red.
It tastes sour.
It is short.
Quantitative
6 foot 3 inches
145 lbs
98.6oF
0.45 meters
using qualitative data.
Scientific Concepts Review
Mixed Review:
1. Identify the following as either a good hypothesis (G) or bad hypothesis (B).
a. If a hermit crab is given a choice between shells, then it will pick the most colorful
shell.
b. If there are clouds, then it might rain.
c. The height of the plant is not affected by temperature.
d. If sugar is added to cold water, then it will not dissolve as well as if it were added to
warm water.
e. The football team will do better this year.
f.
My dog is smarter than your dog.
g. If I drink caffeinated tea at night, then then it will take longer to fall asleep.
2. Determine if the following is a theory (T), law (L), or hypothesis (H).
a.
Force equals the mass multiplied by the acceleration.
b.
If leaf color is affected by temperature, then lowering the temperature will cause a
green leaf to change color.
c.
Evolution states that species of organisms change over time because of changes in
inherited physical or behavioral traits.
d.
For a fixed amount of an ideal gas kept at a fixed temperature, the pressure and
volume are inversely proportional.
e.
With the development of the microscope, scientists found that all organisms are
composed of cells and all cells come from other cells.
f.
If I add salt to water, then the boiling point will lower.
3. For the upcoming science fair, you want to determine if a white or colored candle takes longer to
melt down.
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Create a hypothesis and underline the independent and dependent variable.
Describe the experimental design that will test your hypothesis.
4. Change the following statements into a good hypothesis.
Adding salt to the soil may affect the growth of grass.
Plants will grow better in soil than in just water.
Cinnamon oil can help repel mosquitos.
Temperature affects how quickly bread molds.
5. Pick a hypothesis from question #4 and identify the independent and dependent variables. What
would be your control and experimental group?
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