Nature of Science Practice Test
(Write all answers on answer sheets that follow the test)
1. George likes to race paper airplanes. A friend told him that bending the wings up at a
higher angle will make the planes go faster. He makes five airplanes with the following
wing angels:
Degree of Bend
Plane A: 10 degree bend
Plane B: 20 degree bend
Plane C: 30 degree bend
Plane D: 40 degree bend
Plane E: no bend in wings.
Race Times
Plane A: 50 seconds
Plane B: 38 seconds
Plane C: 35 seconds
Plane D: 30 seconds
Plane E: 57 seconds
a) Give a hypothesis for his experiment.
b) Which Plane was his control?
c) What is the independent variable?
d) What is the dependent variable?
e) Construct a graph using the race times and wing angels.
f) Evaluate the validity of the experiment and the data. What can George
conclude?
2. You want to observe effects of acid on different materials. You know you will need to
wear safety goggles. List 2 other safety precautions you would take in the space
provided.
3. On the answer sheet mark each question below as either being a black box question or
not. Explain briefly why you chose as you did for each one.
a. What type of fertilizer will make plants grow biggest?
b. Why do people get more colds in the winter than in the summer?
c. What caused the ice ages?
d. Does eating chocolate cause changes in mood?
e. How many milligrams of salt are needed to kill a garden slug?
4. The owners of a cookie factory have contacted your science investigative team because
they have a serious problem. The cookies have become contaminated with bacteria
and people are getting sick. Recently, the factory changed one of the ingredients in the
cookies. One of the owners noted that, “We used to use oil in our cookies but we
switched to apple sauce because it is healthy,” she said, “maybe the applesauce is
contaminated!” Also, a member of your team pointed out another possible source of
contamination. On his way through the factory he noticed that many of the workers
weren’t wearing gloves. He commented that, “ Hands carry a lot of bacteria from place
to place, maybe one of the workers has been contaminating the cookies by accident”
Design a valid experiment to help the cookie factory owners find out where the source
of the contamination is. Use the answer sheet format for your work.
5. You may have noticed that every year we experience a change of seasons. You might
also have noticed that Florida does not seem to experience this change as dramatically
as we do. Come up with a theory/model to explain these observations. It does not have
to be correct but it does have to use logic and evidence, it does have to explain all of
the observations or else admit that you can’t explain them. Your theory should also apply
Occam’s Razor. A drawing below may help you get started. Also you may want to
review question 6 first since it mentions a common misconception about the seasons.
This picture shows the Earth’s position in its orbit as we go around the sun. An equinox
occurs when there are equal hours of day and night and a solstice occurs when the day is
either the longest of the year or the shortest of the year in terms of the hours of sunlight.
6. A common misconception about the cause of the seasons is the idea that we are closer
to the sun in winter and further away in the summer. Use the picture above to explain
why this idea cannot be correct. Explain why people might think this (where is the
mistake coming from in their thinking?)
The Nature of Science Practice Test
Name: _______________________________________
Period: ______
1. George’s Experiment
Hypothesis
Airplanes with higher wing angles will fly faster.
Control Plane Plane E; no bend in the wings.
Independent
Variable
Dependent
Variable
Wing angle
Time the airplane stays in the air.
Changes in Flight Time Due to Changes in Wing Angle
Graph: Don’t
forget to
create a title
and to label
each axis of
your graph.
60
40
Fly Time in
Seconds
20
0
0
10
20
30
40
Wing Angles in Degrees
Evaluation of
Validity
This experiment could be made more valid with a few simple changes. There is
a control group in the form of the plane that has no bend in its wings.
However, the experimenters have not included details about how the
experiment was run. All variables except for the angel of the wings need to be
kept constant. The same basic airplane design must be used each time and
there must be a standardized procedure for flying and timing the planes. Also,
there needs to be at least three repeated trials for each plane in order to
minimize the impact of possible sources of error.
2. List two safety precautions you would take for the experiment:
a. Stand while working to avoid spilling on legs.
b. Wash hands thoroughly BEFORE removing goggles.
3. Black box or not:
Letter Fill in the circle next
to one of these.
Explain your choice
a
NO. The experiment will show you which plants grew
faster.
b
c
d
e
o Yes, it is a
black box
o No it isn’t a
black box
o Yes, it is a
black box
o No it isn’t a
black box
o Yes, it is a
black box
o No it isn’t a
black box
o Yes, it is a
black box
o No it isn’t a
black box
o Yes, it is a
black box
o No it isn’t a
black box
YES. Why questions are almost always black boxes. We
can tell how many colds you get, when you get them
and what other factors seemed to coincide with you
getting a cold but we can never be sure what exactly
caused your cold.
YES. We can’t go back in time and see for ourselves
and even if we could it is almost impossible to
definitively show cause and effect between two
variables. All we can do is gather evidence and make
a reasonable theory based on what we have observed.
Sort of. I can take yes or no for this one. Yes, we can
see if your mood changes when you eat chocolate but
are we ever sure what causes what? Not completely.
Still, I lean towards NO for this one. What about you?
NO. We can directly measure this so it isn’t a black box.
It is, however, cruel to the slugs and I highly recommend
leaving the poor critters alone. Use slug deterring plants
to keep your garden slug free!
4. Fill in the experiment sheet.
Problem or question to
investigate
Hypothesis (don’t forget a
rationale)
What is contaminating the cookies?
The cookies are contaminated by the applesauce
Procedures (must be in list
format)
Validity measures: (explain
steps you will take to make
sure your data can be
trusted)
Data plan (create an
empty data chart for
recording your data)
1. Use the regular cookie recipe to make twenty identical
batches of cookies using oil instead of applesauce. Test each
batch for bacterial contamination.
2. Use the same cookie recipe to make twenty identical batches
of cookies using applesauce instead of oil. Test each batch for
bacterial contamination.
3. Compare the amount of contamination in the control group
with the contamination in the experimental group.
In order to make the experiment valid we are running twenty trials.
This should minimize outliers due to sources of error. We also will keep
all the variables constant between the experimental and control
group except for the change from applesauce to oil. For example,
all the other ingredients in the cookies will be the same and the same
workers will produce both batches using the same procedures and
the same equipment. Also, we will have a control group to compare
our experimental group to; the oil cookies.
Effects of different ingredients on bacteria count in cookies
Ingredient Used in Cookies
Cookies made with Applesauce
Cookies made with Oil
Average Bacterial Count for all
twenty trials
5.
Observations
Here in NJ the seasons change as
the year progresses. It is cold in the
winter and there are fewer hours of
daylight.
In summer in NJ the days are
warmer and there are more hours
of daylight
Explanation
The drawing shows that we tilt away from the sun in the
Northern hemisphere during our winter. NJ is fare
enough above the equator for this tilt to create a large
change in the angle of the sunlight. In winter the
sunlight hits us with an nearly flat angle and so it spreads
out more and causes temperatures to drop. It also
means we tilt away from the light enough to cause our
hours of daylight to be shortened. We literally spend
more hours facing away from the sun in the winter.
In summer we tilt into the sun and this makes the light hit
us more directly. We also get a longer time in the sun as
we revolve.
In Florida the days are slightly longer Florida is much nearer the equator. The equator is
and slightly warmer in the summer
almost perpendicular to the sun’s rays no matter which
but the difference is much milder.
way the Earth tilts. As a result, the hours of daylight and
the angle of the light remain fairly constant year round.
6. The reason people think this diagram explains the seasons is that they see the Earth
getting closer and farther away from the sun as it moves in an elliptical path. However, if
this was what was causing the change in temperature then we would have two winters
and two summers every year. This is clearly untrue. The reason we have seasons is
actually because of the Earth’s tilt. When we are tilting into the sun we experience direct
sunlight that is very warm. When we tilt out of the sun we are experiencing indirect
sunlight that is very cool.