Practice Test- Models and Patterns
DO NOT DO the HIGHLIGHTED items
Models & Technological Design
1. Part of a bird's digestive tract, called a gizzard, is able to break up large chunks of food at an
extremely fast rate. It is difficult for scientists to watch a gizzard functioning in a live bird. How
would building a model of a gizzard help a scientist?
A. to watch a gizzard functioning in life
B. to analyze how a gizzard works
C. to determine what type of tissues a real gizzard is made of
D. to study bird behavior
Systems & Patterns
2. Below is a graph that shows the eating habits of a goldfish in an aquarium over a 2-day period.
Which of the following conclusions is supported by the information on the above graph?
A. Fish have a 24-hour circadian rhythm.
B. Fish do not have internal responses to any natural cycles.
C. Fish have a 6-hour circadian rhythm.
D. Fish have a 12-hour circadian rhythm.
Models & Technological Design
3. Brittany wants to use a model to study soil erosion on hills. She is told that farmers can
prevent soil erosion by plowing so that their furrows run along hills instead of up or down hills.
She fills a pan with dirt, packs the dirt firmly, then shapes it into parallel furrows.
What should Brittany do with her pan of dirt next in order to study soil erosion?
A. shake the pan rapidly back and forth
B. set it outside and check on it every day
C. fill the pan with water, then tilt it until all the water runs out
D. prop up one end of it to make a slope and carefully pour water over it
Systems & Patterns
4. A system is a group of related parts with specific roles that work together to achieve an
observed result. The flow chart below shows a communication system.
In this communication system, what does the transmitter do?
A. converts the message to a signal and sends it to a receiver
B. detects electrical signals produced by the receiver
C. modulates the signal so that it cannot be interpreted by the receiver
D. converts the message from electrical energy into sound energy
Models & Technological Design
5. Stella has poured 3 cups of water into a 1-L soda bottle. Stella then sealed the bottle and
placed it in the sunlight. What natural process can Stella study with the model she built?
A. nitrogen cycle
B. carbon cycle
C. water cycle
D. rock cycle
Systems & Patterns
6. When looking at a maple tree, you learn that many maple tree leaf cells are capable of creating
food from the sun and sustaining the whole plant. However, if you take a green leaf from a maple
tree, the leaf dies. What does this tell you about the difference between the properties of a system
and the properties of its parts?
A. Maple leaves are unable to create food from sunlight.
B. Your particular maple leaf did not contain enough cells that create food from sunlight.
C. Maple leaves need to be connected with the whole maple tree system to survive.
D. Maple leaves cannot be a functional part of the maple tree's system.
Systems & Patterns
7. Sending an e-mail is an example of a system with multiple parts.
An e-mail program takes the input from the keyboard and changes it into a computer language
output. The output language goes through the internet system and finds the account it was sent
to. The message becomes the input for another e-mail program which changes it into an output of
text that the recipient can read.
What is the primary type of input and output that is used in an e-mail system?
A. information
B. biological
C. energy
D. material
Systems & Patterns
8. What do the lunar cycle, bird migration, and cell mitosis have in common?
A. They are all natural events that occur in a pattern.
B. They are all included in the discipline called biology.
C. None of them are studied by scientists today.
D. None of them are predictable.
Systems & Patterns
9. The flowchart below represents a system.
What is the input in this system?
A. body temperature
B. sweat gland activity
C. blood vessel diameter
D. the brain
Models & Technological Design
10. Ringo designs a stapler that his class can use to staple large stacks of paper together. He
gives it a very long handle, so that enough leverage can be applied to push a staple through up to
50 sheets of paper.
When he builds his design, he finds that after the handle is pushed down, the stapler does not
return to its original, upright position. What is the best way for Ringo to correct this design flaw?
completely abandon his design and build something else.
A.
B.
C.
D.
add a spring that will push the stapler upright after it is used.
make the handle shorter, so that more force will need to be applied.
make the handle longer, so that it can staple through up to 100 sheets of paper.
Models & Technological Design
11. Many companies make permanent coffee filters like the one below.
How is this an improvement on the traditional, paper coffee filters?
A. They are less wasteful and more cost effective because they last longer.
B. A permanent filter is more expensive than a traditional filter.
C. They contain plastic which does not break down as easily as paper.
D. The coffee brewed using permanent filters does not taste as good.
Models & Technological Design
12. Cotton balls could be used to represent clouds because of their white color and appearance of
texture. Which of these other things could be modeled using cotton?
A. the Sun
B. rain
C. a tree
D. cobwebs
Models & Technological Design
13. Trey was asked to build a working model of a landform for a science project. He chose to
build a model of a volcano.
Trey formed a base out of clay and then painted the model so it resembled a cinder cone volcano.
Finally, Trey mixed baking soda, vinegar, and red food coloring in the base, so it mimicked lava
flowing out of the volcano. Once he was finished with his project, Trey's teacher asked how
useful his model was.
What factor best determines the usefulness of the model?
A. how closely the model's composition matches the real world
B. how closely the model's size matches the real world
C. how closely the model's behavior matches the real world
D. how closely the model's color matches the real world
Systems & Patterns
14. The circulatory system of a mouse includes a heart that pumps blood into a network of blood
vessels throughout the body. The blood provides the cells of the body with nutrients and oxygen.
If the heart of a mouse stops pumping blood, how will this effect the rest of the mouse's
circulatory system?
A. The mouse's cells will receive an excess of oxygen.
B. Blood will no longer flow through the mouse's blood vessels.
C. The mouse's circulatory system will function normally.
D. Blood will flow faster through the mouse's blood vessels.
Systems & Patterns
15. The body's nervous system is made up of the brain, the spinal cord, the retina, and many
other nerves. The circulatory system is made up of the heart, arteries, veins, and capillaries.
The nervous system tells the heart when to beat, and the circulatory system supplies nerve cells
with blood.
Which of the following best describes the relationship between the nervous system and the
circulatory system?
The circulatory system is a subsystem of the nervous system.
A.
B.
C.
D.
The circulatory system and the nervous system depend on each other.
The nervous system and the circulatory system do not affect each other.
The nervous system is a subsystem of the circulatory system.
Models & Technological Design
16. Samantha is developing a new design for a nuclear reactor. Why might she want to make a
detailed computer model of her design?
I. to test the physical theories behind nuclear energy
II. to test the reactor's safety systems
III. to test the reactor's energy output
IV. to measure the effects of radiation sickness
A. III and IV only
B. II and III only
C. I and II only
D. I only
Systems & Patterns
17. A system is made up of several parts that
A. work independently to perform several related tasks.
B. work together to perform a single task.
C. work opposite one another to perform unrelated tasks.
D. work independently to perform unrelated tasks.
Models & Technological Design
18. Sariah's science teacher asked everyone in the class to bring a model of the park near their
school so that they could add labels to them in class. To which kind of model would it be easiest
to add labels?
A. a scale-model sculpture out of clay
B. a scale drawing, looking down on the park
C. a scale drawing of a cross-section of the park
D. a scale-model diorama made of dirt and sticks
Models & Technological Design
19. Marty is developing a new way to heat an airplane's windshield to prevent it from
accumulating ice when in flight. A thin layer of clear, conductive material is injected between
two layers of thick windshield plastic. A very small electric current is run through the inner
material to keep the plastic layers warm.
How might using a model help Marty develop his design?
A.
B.
C.
D.
Airplane manufacturers could be sold models to use in their new planes.
Marty could use a model to discover a new type of plastic for windshields.
A model could be used for automobile windshields.
A model could be used to test his design in a lab.
Systems & Patterns
20. For the past four years, Mr. Thompson has kept a pet boa constrictor in his science
classroom. At the beginning of each year, his students measure the length of the snake and record
the result.
The table below shows the measurements for all four years.
Year
Length (cm)
1
120
2
190
3
260
4
330
What is the growth pattern of the boa constrictor?
A. It grows 7 centimeters each year.
B. The amount it grows changes every year.
C. It grows 70 centimeters each year.
D. It doubles in size every year.
Models & Technological Design
21. Quantum physicists are scientists who study the inner workings of atoms. To do this,
quantum physicists often rely on models. Why do quantum physicists typically use models to
study atomic particles instead of observing atomic particles directly?
A.
B.
C.
D.
Atomic particles no longer exist, so physicists can no longer observe them directly.
Atomic particles are too small to be easily observed directly.
Atomic particles move too slowly for physicists to be able to study them directly.
Atomic particles can be very dangerous to observe directly.
Systems & Patterns
22. What is system input?
A. Feedback from scientists about the results of a system
B. The ordered processes that the system uses to change raw material
C. Raw material that must be put into a system for processing
D. Material that has been changed by a system
Systems & Patterns
23. The flowchart below shows the major steps in a system that builds mp3 players.
Which of the steps in the system are examples of processes?
A. I, III, and V only
B. II and IV only
C. I, II, III, and IV only
D. I, II, III, IV and V
Models & Technological Design
24. What do engineers use to test their designs of new technologies?
A. models
B. pie charts
C. polls
D. reference materials
Systems & Patterns
25. When a system is behaving erratically, a graph of data measured from the system
A. takes the shape of a line.
B. cannot be recorded.
C. does not form a pattern.
D. takes the shape of a wave.
Models & Technological Design
26. The main goal of science is to
A. learn about the universe and the laws of nature.
B. learn how to use the laws of nature to benefit humans.
C. replace old theories with new, more interesting theories.
D. develop new inventions and processes.
Models & Technological Design
27. Which of the following best describes the difference between science and technology?
Scientific principles must be supported by evidence and data, while technological
A. principles do not require evidence and data.
The goal of science is to gain knowledge about the natural world, while the goal of
B. technology is to create new processes or products for human use.
Technological principles must be supported by evidence and data, while scientific
C. principles do not require evidence and data.
The goal of technology is to gain knowledge about the natural world, while the goal of
D. science is to create new processes or products for human use.
Systems & Patterns
28. The finished product or waste that forms as a result of a process is known as _______.
A. the output
B. positive feedback
C. the input
D. negative feedback
Models & Technological Design
29. A company is developing a new type of airplane that can take off like a helicopter. Before
they begin manufacturing the airplanes on a large scale, they first build a prototype. What is the
main purpose of building a prototype?
A. to train factory workers about how to make the product on a large scale
B. to make sure the design works as expected
C. to find a market in which to sell the product
D. to show future customers what the product will look like
Systems & Patterns
30. The cell is the basic building block of all living organisms. In multicellular organisms, cells
are organized into tissues that can, in turn, be organized into organs. Organs can also be grouped
into the many organ systems that make up a whole organism.
This example shows how
A. the failure of one part of a system will not affect the whole system.
B. parts of a system can be placed in order from simple to complex.
C. the parts of a system do not have to be related.
D. some parts of a system are more important than others.
Systems & Patterns
31. Ten years ago, the ratio of birds to snakes in a local desert ecosystem was 2:5. Over the last
10 years, disease and hunting by humans has cut the bird population in half. The snake
population has not changed. What is the current ratio of birds to snakes in this local ecosystem?
A. 1:5
B. 2:5
C. 1:2
D. 2:2.5
Systems & Patterns
32. The following table describes four different systems.
System
Description
food web
Both matter and energy are exchanged with other systems.
carbon
cycle
Energy is exchanged with other systems, but the amount of carbon remains
constant.
water cycle
The amount of water remains constant, but energy is exchanges with other
systems.
universe
The amount of matter and energy remain constant.
Which is an example of an open system?
A. the water cycle
B. the carbon cycle
C. the universe
D. a food web
Systems & Patterns
33. What is "change" when we are talking about natural and physical systems?
A. A variable or alteration to one part that affects an entire system
B. Information that has been proven to be true
C. A process for using knowledge and skills to acquire new knowledge
D. Repeated processes that are used in a variety of ways
Systems & Patterns
34. There are five elements of a universal systems model: goal, inputs, processes, outputs, and
feedback. Which of the following describes the "processes" portion of this model?
A. the results of the system
B. what is done to the inputs
C. information collected from the outputs
D. the money, time, and resources used on the model
Systems & Patterns
35. In class, Samantha is told to draw a graph of the length of the day versus the time of year.
She is given only the following information to work from:
At a certain latitude, the number of hours of daylight changes from more
than 14.8 hours on the summer solstice to about 9.2 hours at the winter
solstice.
Samantha draws the following graph:
How is this graph a good or bad presentation of the information she was given?
It is a bad presentation because at least two cycles must be graphed in order to show that
A. the data is a cycle.
It is a bad presentation because the day length peaks at the end of the graph, as well as in
B. the summer.
It is a good presentation because it shows the entire length of the cycle, including all the
C. information she was given.
It is a good presentation because it includes more details than the information she was
D. given did.
Models & Technological Design
36. The phases of the moon are caused by the changing positions of the Earth and the Moon in
relation to the Sun.
Which items could best be used to represent the Sun, the Earth, and the Moon in a model that
shows the phases of the Moon?
A. a flashlight, a basketball, and a softball
B. a candle, a soccer ball, and a mirror
C. an orange, a grapefruit, and a lime
D. a mirror, a fan, and some string
Models & Technological Design
37. Scientists use sonar machines in order to map the contour of the ocean floor. The data from
the sonar machines make a model of the ocean floor. What information can be obtained from this
model?
A. what sort of landforms are found on the ocean floor
B. how old the ocean's crust is
C. what temperature the water is near the ocean floor
D. what sort of organisms live near the ocean floor
Models & Technological Design
38. Conrad learns that one way an oil spill on the ocean is handled is by scattering dispersants on
it. His teacher tells him that dish soap and laundry detergent act as dispersants. Conrad uses two
pans of water to model the ocean. He adds oil to one pan.
How can Conrad use dish soap with his model to study how adding dispersants to oil spills
would help protect water birds from the oil?
Add oil to the second model, add dish soap to it, then wash one dish in each pan.
A.
Add dish soap to the second pan, then place them both outside to see which one birds
B. would rather drink from.
C.
D.
Mix dish soap into the second pan, then add oil on top of it.
Add oil to the second pan, add dish soap to it, then dip one feather in each pan.
Models & Technological Design
39.
Lillian wonders how fast a train can move around a particular curve before it falls off of the
track. Which of the following is the best way for Lillian to figure this out?
Drive a train along a curve at different speeds until it falls off of the track.
A.
Build a model train and track, and test one train going around one curve at different
B. speeds.
Build a model train and track, and test different-sized trains going around one curve at the
C. same speed.
Build a model train and track, and test one train going around several different curves at
D. one speed.
Systems & Patterns
40. A system is a group of many simple parts and processes that influence or interact with each
other. The human body is a system that is made up of many organ systems.
Which of the following is most likely to occur if a person has a disease of the digestive system
that damages their small intestine?
A. The body will no longer continue to function normally.
B. Only the digestive system will be affected.
C. The body will continue to function normally.
D. Only the small intestine will be affected.
Models & Technological Design
41. A company is announcing the construction of a new skyscraper to the public. Which model
will give the best idea of how the new building will change the city skyline?
A. a full scale, three-dimensional model of the building
B. a drawing showing the interior of the building
C. a drawing showing both the new and old buildings
D. a rough sketch of the building's shape
Models & Technological Design
42. Science and technology often develop simultaneously. That is, scientific discoveries often
lead to the development of new technology, and technological devices allow new scientific
discoveries to be made.
What technological design allowed scientists to determine differences in the internal structures of
plant and animal cells?
A. microscopes
B. seismographs
C. telescopes
D. barometers
Models & Technological Design
43. Volcanologists are scientists who study volcanic eruptions. However, most volcanologists
rarely get to witness a volcanic eruptions actually occurring. Instead, many volcanologists use
models to study volcanic eruptions. What is the most likely reason why volcanologists often rely
on models to study volcanic eruptions?
A. Volcanic eruptions are too large to be able to see with the naked eye.
B. Volcanic eruptions take too long to be able to be observed in their entirety.
C. Volcanic eruptions are very dangerous events.
D. Volcanic eruptions are rare occurrences so it is difficult to see them.
Systems & Patterns
44. A system is a group of related parts with specific roles that work together to achieve an
observed result. Seeds, soil, a plow, and a large field are parts of what type of system?
A. an agricultural system
B. an urban system
C. an organ system
D. a legal system
Models & Technological Design
45. Abigail just completed a report on plastics, which are manufactured using petroleum. She
concluded that the price of plastic will likely rise significantly in the years to come as petroleum
reserves are depleted. She recommends that manufacturers begin making less plastic from
petroleum reserves to prevent extreme price increases in the future.
Abigail's younger brother Henry just completed a report on waste management. Henry concluded
that plastic products are a major component of garbage that ends up in landfills. He recommends
that humans reduce the amount of plastic they put in landfills.
Which of the following would help implement both Abigail's and Henry's recommendations?
A. Reuse more plastic products.
B. Use alternatives to plastic products.
C. Recycle more plastic products.
D. all of these
Systems & Patterns
46. What is an open-loop system?
A. A group of related objects that make up a larger system
B.
A group of related objects that do not send out or receive feedback and cannot modify
themselves
C. A group of related objects that send out and receive feedback and can modify themselves
D. Any device used to extend human capability
Systems & Patterns
47. What does the motion of a hurricane have in common with the seasons of the year?
A. Neither of them is predictable.
B. Both of them follow a pattern.
C. Neither of them is studied anymore.
D. Both of them can only be observed through a telescope.
Systems & Patterns
48. Brent is running on a hot day. His body operates best when its inner temperature is 98.6°F.
If Brent's body temperature climbs above 98.6°F, what will keep it from climbing too high?
A. negative feedback provided by sweat
B. positive feedback provided by the heart
C. negative feedback provided by rain
D. positive feedback provided by blowing wind
Models & Technological Design
49. Stuart designed and built a water filter in class. He wants to know if it will make water from
lakes or streams safe to drink. Which of the following would it be best for Stuart to measure in
an experiment in order to test his design and answer this question?
A.
B.
C.
the maximum force that can be applied to his filter without breaking it
the amount of time required for different volumes of water to pass through his filter
the diameter of the largest grain of dust, dirt, or sand that can pass through his filter
D. the amount of bacteria and impurities in water both before and after it passes through his
filter
Models & Technological Design
50. Dr. Ray has developed a new way to remove oil from wetlands in the event of an oil spill. To
test his new process, Dr. Ray builds a scale model of a wetland in his lab and pours a small
amount of oil into it. He then observes the rate at which his process is able to remove the oil
from the model.
Why did Dr. Ray use a model?
A.
B.
C.
D.
Because real wetlands are too complicated for his process to work.
Because dumping oil in a real wetland would be dangerous.
Because his model makes the process more complicated.
Because real wetlands are too large to be affected by oil.
Systems & Patterns
51. The power grid is the system that transfers electricity to homes and business.
A power plant produces electricity. The output electricity is an input for the wires that lead to
power substations. The power substations regulate the flow of electricity and send it as an output
through different wires. Transformers adjust the electricity along the way until it becomes an
input for a home.
What is the primary type of input and output that is used in the power grid system?
A. biological
B. material
C. information
D. energy
Models & Technological Design
52. Newton's Third Law of Motion states that for every action there is an equal and opposite
reaction. Science teachers often model this law by showing what happens when two floating
balls collide in a pool of water.
What is the most likely reason that science teachers explain this law by modeling it?
The law is an abstract idea that may be difficult to understand without seeing how it
A. works.
B.
C.
D.
The objects governed by the law are too dangerous to be observed directly.
The law does not apply to any objects found on Earth.
The objects governed by the law are too small to be easily observed directly.
Systems & Patterns
53. In which of the following systems does an output of physical material become the input for
another part of the system?
A. power grid system
B. telephone system
C. carbon cycle system
D. computer processor
Models & Technological Design
54. One of the biggest challenges for the exploration and future colonization of space is the
expense of launching materials from Earth. Current rocket propulsion technology makes
launches very expensive. Every item launched into space must be considered carefully because
the expense goes up with every extra pound of cargo.
This problem would be best solved with
A.
B.
C.
D.
heavier, more durable rockets and launching methods that are less cost-efficient.
heavier, more durable rockets and launching methods that are more cost-efficient.
launching methods that are more cost-efficient and cargo made of lighter materials.
launching methods that are more cost-efficient and cargo made of heavier materials.
Systems & Patterns
55. Which of the following is an example of an open-loop system?
A. setting an automatic sprinkler system
B. setting the thermastat to 72°
C. steering a car
D. dialing a phone number
Models & Technological Design
56. Cancer is a disease in which abnormal cells divide at an uncontrollable rate. Over time, many
different techniques have been used in an attempt to answer the following scientific question,
"How can cancerous tumors be killed in a way that causes the least amount of damage to the
patient's normal tissues and cells?"
In 1600 BC, Egyptians tried to kill tumors using a "fire drill."
In the 1000s, Persian doctors tried to kill tumors using chemicals, such as arsenic. Over
time, new chemicals have been synthesized, and this technique is still being used in
cancer treatment today.
In the 1700s, European doctors tried to surgically remove tumors, but this technique did
not become effective until later when antiseptics and anesthesia were invented. The
invention of laser technology and surgery in the 1900s also greatly improved the
effectiveness of this form of treatment.
In the late 1800s and early 1900s, French doctors began using radiation therapy. This
technique, which is also still being used today, has been improved with the invention of
CT and MRI scanners and better particle accelerators which help doctors to more clearly
identify the location of tumors and focus the radiation on the tumor itself rather than on
adjacent tissue.
The above example shows how
it is impossible to answer any scientific questions.
A.
certain scientific questions can be answered through the invention of new technological
B. designs.
C.
all scientific questions can only be answered through controlled scientific experiments.
D. all of these
Systems & Patterns
57. A cycle is a series of events that repeats in a regular pattern. Which of these is a cycle?
A. the hatching of an egg
B. a major flood
C. the seasons of the year
D. a basketball game
Systems & Patterns
58. _______ is a system in which both matter and energy flow into and out of the system.
A. An open system
B. A dynamic system
C. An isolated system
D. A closed system
Models & Technological Design
59. Amy is designing a telescope that, when completed, will orbit the Earth from outer space.
She can use models to do which of the following?
I. plan the orbital path of the telescope
II. illustrate the dimensions of the satellite
III. collect images of far-off stars and galaxies
IV. manufacture the telescope's primary mirror
A. I and II only
B. II and III only
C. III and IV only
D. II and IV only
Models & Technological Design
60. If two engines are given the same amount of fuel, the more efficient engine can do more
work than the less efficient engine can. The following questions could be asked to help make
scientific or technological progress. Which of the following questions is best asked and answered
as part of a scientific investigation, not as part of technological improvements?
A. How can efficient engines be built more cheaply?
B. How efficient can an engine be, in theory?
C. How can a more efficient engine be built?
D. How can the efficiency of an existing engine be improved?
Answers
1. B
2. A
3. D
4. A
5. C
6. C
7. A
8. A
9. A
10. B
11. A
12. D
13. C
14. B
15. B
16. B
17. B
18. B
19. D
20. C
21. B
22. C
23. B
24. A
25. C
26. A
27. B
28. A
29. B
30. B
31. A
32. D
33. A
34. B
35. C
36. A
37. A
38. D
39. B
40. A
41. C
42. A
43. C
44. A
45. D
46. B
47. B
48. A
49. D
50. B
51. D
52. A
53. C
54. C
55. A
56. B
57. C
58. A
59. A
60. B
Explanations
1. Models represent objects, events, and processes in the real world.
Models are often used when an object, event, or process
occurs too slowly or too quickly;
is too small or too large;
is too complicated or too dangerous.
Scientists often use models of organs to analyze how that organ works and what would happen
should that organ fail. Models of organs are useful because it is very difficult to observe a
working organ in a living organism.
2. Circadian rhythms are daily cycles in animals controlled by their biological clocks. The fish in
the aquarium complete an entire feeding cycle between 9 AM Monday and 9 AM Tuesday. This
is a 24-hour time range. Fish are only finished with half of this cycle by 9 PM. All known
animals have internal responses to at least one natural cycle, such as the length of the day or the
position of the moon.
3. Brittany should prop up one end of the pan to make a slope to model a hill. Then she should
carefully pour water over it to model rain and irrigation.
4. Each part of a system has a specific role, and all the parts of the system must work together in
order to achieve a desired result. If one part of the system isn't functioning properly, then the
whole system is unable to function properly.
A transmitter converts a message, usually into electricity, light, or radio waves. The converted
message is then broadcast out so that it can be picked up by a receiver. Without the transmitter,
the communication system would not function properly.
5. Models are representations of objects, events, and processes in the real world. But, different
models can be used to represent the same thing. The purpose of the model must be considered
when choosing which type of model to use.
Stella can use her model to study the processes of evaporation and condensation, two major
processes that drive the water cycle.
6. A maple tree is a system composed of many parts. Each part plays a different role in the
system, but all the parts interact with each other.
A maple leaf is able to transform sunlight into food that sustains the whole system. However, a
maple leaf needs the rest of the system to survive and grow. If one part of the system is not
working properly, the whole system will not function properly.
7. The primary input and output of an e-mail system is information. The information in the
email is changed into different forms as it travels through the system.
Energy is used in the process, but it is not the primary form of the input and output.
8. All of the natural events in the list have a predictable recurring pattern.
In fact, most natural events occur in patterns. Scientists often look for patterns when studying a
new phenomenon.
9. An input is the information entering a system. In this system, body temperature is the
information that can cause a response by the brain.
10. Ringo could add a spring that will push the stapler upright after it is used.
Engineers very often discover flaws in the designs of technological systems. When this happens,
the original design is usually modified to correct the flaw.
11. Permanent coffee filters are becoming more popular because they are less wasteful and
more cost effective because they last longer. Traditional, paper filters can only be used once,
whereas a permanent filter can last years. However, paper filters break down easily in the
environment. Permanent filters are made from plastic and metal. The plastic takes years to break
down in a landfill.
12. Models are frequently used to represent objects, events, and processes in the real world. But,
different models can often be used to represent the same thing. The purpose of the model must be
considered when choosing which type of model to use.
Cobwebs are white and stringy. When cotton is stretched, it is also white and stringy.
13. Models are often created to represent objects, events, and processes in the real world that
occur too slowly or too quickly;
are too small or too large;
are too complicated or too dangerous.
Although a model's appearance may be similar to the object that is being modeled, the usefulness
of a model is best determined by how closely its behavior matches the real world.
Models are often used to get a better idea of how an object works or how an event or process
occurs. However, if a model is used as the only source of data, there is no guarantee that
hypotheses or conclusions made about the real world object will be correct.
14. A system is made up of interrelated parts that work together to perform a single task. If any
of the parts of the system are changed, the entire system will be affected.
If a mouse's heart stops pumping blood, blood will no longer flow through the mouse's blood
vessels.
15. Systems are often connected to other systems.
The nervous system performs many special jobs, but it cannot work without the circulatory
system. The circulatory system also performs many special jobs, but it cannot work without the
nervous system. In general, the nervous system tells the heart when to beat, and the circulatory
system supplies nerve cells with blood. So the circulatory system and the nervous system
depend on each other.
16. Engineers use models to help them develop new or improved technologies. Models allow
engineers to test a design to see how it will perform in the real world. A computer model of a
nuclear reactor could help an engineer test the reactor's safety systems, test the reactor's
energy output, or to test any other of the reactor's processes.
17. A system is made up of interrelated parts that work together to perform a single task.
There are thousands of systems at work every day in society, in machines, and in our own
bodies. An example of a system is the digestive system, which includes the stomach and the
intestines. These organs and others work together to digest food.
Systems can also be made up of interrelated processes. For example, energy production in plants
is a system that consists of two main, interrelated processes - photosynthesis and respiration.
18. Different models can be used to represent the same thing. The type of model chosen depends
upon the purpose of the model.
Sariah's teacher wants the students to be able to add labels to their models. A scale-drawing of
the park, looking down on it, would make that easiest.
19. Engineers use models to help them develop new or improved technologies. Models allow
engineers to test a design to see how it will perform in the real world. So Marty can use a model
to test his design in a lab, before it is used in real airplanes. This process will ensure that
Marty's deign is both effective and safe.
20. To determine how much the snake has grown each year, subtract the first year's measurement
from the second year's, the second year's from the third year's, and the third year's from the
fourth year's.
First year's growth = 190 cm - 120 cm = 70 cm
Second year's growth = 260 cm - 190 cm = 70 cm
Third year's growth = 330 cm - 260 cm = 70 cm
The difference is 70 cm each time, so the snake's growth pattern is that it grows 70 centimeters
each year.
21. Models represent objects, events, and processes in the real world.
Models are often used when an object, event, or process
occurs too slowly or too quickly;
is too small or too large;
is too complicated or too dangerous.
Atoms, the building blocks of matter, are extremely tiny. They can only be seen using an
electron microscope. The atomic particles inside an atom are even tinier. In fact, over 99.99% of
the space inside of an atom is empty since atomic particles are so small and have such incredibly
diminutive masses.
22. System input is the raw material that is put into a system for processing. In the case of the
digestive system, food is the input. The output is energy and waste. The system process is the
digestion itself, including chewing, chemical breakdown of the food in the stomach, and nutrient
absorption in the intestines.
23. Systems can include processes as well as things. In the system that produces mp3 players,
only steps II and IV are examples of processes. The production process builds the case and the
electronics while the assembly process puts the parts together into a product.
The materials used are inputs to the system. The parts are both an output and an input, and the
product is the final output for the system.
24. Engineers use models when developing new or improved technologies. Models allow
engineers to test a design to see how it will perform in the real world. The advantage of a model
is that flaws or ways to improve a technological design can be discovered before the technology
is fully developed.
25. Systems that behave erratically may provide measureable data. However, that data will have
no apparent pattern in it.
Erratic data cannot be used to model the system or to predict how it will behave in the future.
26. The main goal of science is to learn about the universe and the laws of nature. The main
goal of technology is to make new inventions and processes to benefit humans.
27. Science and technology are closely related, but not exactly the same. Science is the pure
pursuit to gain knowledge about the natural world. The goal of technology is to develop new
processes or products for human use. Technology is based on scientific principles, so technology
relies on science. Both science and technological principles must be supported by evidence and
data.
28. The raw material that is added to a system for processing is known as the input. For example,
the input for the digestive system is food that is eaten.
The finished product or waste that forms as a result of a process is known as the output. For
example, the output of the digestive system is energy and wastes.
When the output of a system comes back to influence the subsequent functioning of that system,
feedback occurs. If the output amplifies subsequent outputs, positive feedback occurs. If the
output causes subsequent outputs to decrease, negative feedback occurs.
29. An engineer starts the product design process by making drawings and notes about his or her
idea. Next, models are built of the design. Once the model is satisfactory, a prototype is built.
The prototype is a key opportunity for the engineer to identify and solve any design problems
before the product is commercially produced.
30. A system is a group of related parts that work together to achieve a result. Often, the parts of
a system can be placed in order from simple to complex.
Within an organism, cells are the simplest part. Tissues, organs, and organ systems are more
complex parts. The diagram below shows how these parts are organized within an organism.
cells → tissues → organs → organ systems → organism
31. The ratio of birds to snakes 10 years ago was 2:5. In this ratio, the number 2 represents the
birds, and the number 5 represents the snakes. There were two birds for every five snakes.
Because the number of birds in the ecosystem has decreased by half, the number 2 is reduced by
half to become the number 1.
Because the number of snakes in the ecosystem has not changed, the number 5 remains
unchanged.
So, now there is one bird for every five snakes, which is a ratio of 1:5.
32. In an open system, both matter and energy can be exchanged with another system.
A food web is an example of an open system because both matter and energy move into and out
of a food web. Energy usually enters a food web in the form of light from the sun, and it exits in
the form of heat. Matter also cycles into and out of food webs. Carbon, for example, enters and
exits a food web in the form of carbon dioxide.
Nutrient cycles, such as the carbon and water cycles, are closed system because the matter
remains constant. This means that matter neither enters or exits the system.
The universe is a special case. Since both matter and energy stay constant within the universe, it
is considered an isolated system.
33. Change is a variable. It can come as a result of new knowledge and better technology. Or it
can happen due to the malfunctioning of a machine or a broken part. It can happen as a result of
feedback that a system receives. All systems deal with change. Change in one part of a system
affects the whole system.
34. A universal systems model is a tool used to try to simply and understand complex systems.
Inputs, such as capital and materials, are used to run a process. The results, or outputs, are
analyzed and feedback is produced.
35. Samantha's graph is a good presentation of the information because it shows the entire
length of the cycle, including all the information she was given.
The most important information when describing a cycle is
how long the cycle takes;
by how much the system changes over the course of the cycle;
at what point in the cycle these changes take place.
36. Models are representations of objects, events, and processes in the real world. But, different
models can be used to represent the same thing. The purpose of the model must be considered
when choosing which type of model to use.
Half of the moon is always in shadow. The phases of the moon are caused by how much of the
light half of the moon is visible from the Earth, which depends on the relative positions of the
Sun, the Earth, and the Moon.
The Sun is best represented by a light source. The Earth and the Moon are both round objects,
and the Moon is smaller than the Earth.
So, a flashlight, a basketball, and a softball could be easily used to represent the Sun-EarthMoon system. One example set up is shown below.
37. Models represent objects, events, and processes in the real world.
Scientists use models of the ocean floor to see how the floor is changing, to study landforms on
the ocean floor, and to compare the geography of the ocean floor with that of the continents.
38. Dispersants can help keep oil from sticking to birds' feathers. Conrad could demonstrate this
by adding oil to each pan, adding dish soap to one pan, then dipping one feather into each
pan.
The image in this question is courtesy of the California Department of Fish and Game/Office of Spill Prevention and Response
39. Lillian should build a model train and track, and test one train going around one curve
at different speeds.
The variable that Lillian wants to change is the speed of the train. She wants to change this until
the train falls off of the track. In this case, Lillian should use a model, since using a real train
would be extremely dangerous. She will also want to make sure she uses the same model train
for each trial and tests it on the same curve.
40. The small intestine is part of the human digestive system. The human body relies on the
digestive system for its nutrients and energy. If part of this system is not functioning, then the
body will most likely become malnourished.
Changing one part of a system can affect the whole system. In this case, changing part of the
digestive system will affect the whole human body. The body will no longer continue to
function normally.
41. Models are frequently used to represent objects, events, and processes in the real world. But,
different models can often be used to represent the same thing. The purpose of the model must be
considered when choosing which type of model to use.
A drawing that shows both the new and the old buildings will allow people to compare the
skyline as it is now to how it will look after construction is finished.
42. Sometimes, scientific questions cannot be answered without the invention of new
technology.
For example, a scientist living in the year 1000 may have wondered, "What is the difference
between the internal structures of a plant cell and an animal cell?" But this question could not be
answered until after microscopes with higher resolutions were invented in the mid to late 1600s.
43. Models represent objects, events, and processes in the real world.
Models are often used when an object, event, or process
occurs too slowly or too quickly;
is too small or too large;
is too complicated or too dangerous.
Volcanic eruptions produce both molten lava and poisonous gases. Therefore, eruptions can be
very dangerous. Many volcanologists have lost their lives while observing volcanic eruptions.
44. Anything that has two or more parts working together is a type of system. Some systems,
such as toothbrushes, are very simple because they only have a few parts. Other systems, such as
farms, can be very complex because they have hundreds of different parts.
The components of a system play different roles in the system.
45. All of these solutions would help implement both Abigail's and Henry's recommendations.
By recycling and reusing plastic products, or by using products made of alternative materials,
there will be less demand for new plastic products to be manufactured. Carrying reusable canvas
shopping bags also reduces the amount of disposable items made of plastic.
All of these practices will also reduce the amount of plastic waste going into landfills.
46. An open-loop system is a system with no feedback; it is the uncontrolled system. In an openloop system, there is no loop connecting the output to the input. If someone is cutting your hair
without looking at your head to see how he or she is doing, that is an open loop. The barber isn’t
getting any feedback about the process.
47. Meteorologists study the weather. They have found that hurricanes occur most often in the
summer months and that they move in a predictable way across the Atlantic Ocean. This means
that, like the seasons of the year, hurricanes follow a pattern.
In fact, most natural event occur in patterns.
48. The output from one part of a system can become the input for other parts. Such feedback
can serve to control what goes on in the system as a whole.
When Brent runs, his body temperature increases. This causes his body to release sweat.
Although sweat is an output of the body's system, it goes back into the system as an input by
cooling the body. Negative feedback provided by sweat helps to keep Brent's body operating
within a healthy temperature range.
49. Although each of these properties of Stuart's filter may be worth testing, the one that will tell
him whether his filter can make lake water safe to drink is the amount of bacteria, parasites,
and impurities in water both before and after it passes through his filter. Some filters are
good at removing impurities, but not bacteria. Other ways of purifying water may kill bacteria
but not remove impurities.
50. Models are often used to think about processes that are too vast to be changed deliberately, or
that are potentially dangerous.
Intentionally dumping oil in a real wetland would be dangerous. So Dr. Ray most likely
chose to build a model so that he could test his cleanup system without harming a real
ecosystem.
51. Electricity is a form of energy. So the input and output of the power grid system is energy.
52. Models represent objects, events, and processes in the real world.
Models are often used when an object, event, or process
occurs too slowly or too quickly;
is too small or too large;
is too complicated or too dangerous.
Newton's laws of motions are abstract ideas. It is sometimes easier to understand abstract ideas
when they are applied to objects in the real world.
53. In the carbon cycle system, the material form of carbon changes as it goes through the
system. For example, the carbon dioxide gas put out by animals becomes an input material for
plants to make solid food.
54. This problem would be best solved with launching methods that are more cost-efficient
and cargo made of lighter materials.
By developing more cost-efficient technology for launching, it will cost less to send cargo into
space. Also, by launching cargo that is made of lighter materials, more cargo can be launched for
the same cost.
55. An open-loop system is a system with no feedback; it is the uncontrolled system. In an openloop system, there is no loop connecting the output to the input. If someone is setting an
automatic sprinkler system, then the system will run for the set time regardless if it is raining or
not. There are no feedback processes to adjust the watering time based on the needs of the lawn.
56. Sometimes, certain scientific questions can be answered through the invention of new
technological designs.
For example, in order to determine the difference in the internal structures of animal and plant
cells, the microscope had to be invented. Or, in order to better understand the surface features of
planets and moons, satellites and high-powered telescopes had to be invented.
Similarly, in order to find a way to find a way to kill cancerous tumors with minimal side effects,
new surgical techniques, chemotherapy, imaging technology, and radiation technology had to be
invented. Cancer research is still active and ongoing, and as new technology continues to be
invented, hopefully treatments will improve as well.
57. The seasons of the year repeat in a predictable pattern of winter, spring, summer, and fall.
The other answer choices are individual events. Parts of these events may repeat. For example, a
team may perform the same play several times during a basketball game. Also, each of these
events may be one step of a larger cycle (e.g., an individual basketball game is one of many
games in a basketball season that repeats every year). But these individual events are not cycles
themselves.
58. An open system is a subsystem, or a system within a system. Both matter and energy are
able to move into and out of an open system.
An organism is an example of an open system because both matter and energy are exchanged
with the environment, another system.
59. Engineers use models to help them develop new or improved technologies. Models allow
engineers to test a design to see how it will perform in the real world.
In this case, Amy might want to build a scale model or make a scale drawing to illustrate the
dimensions of the satellite. This type of model could help her describe to other engineers how
the satellite will look. She might also want to use a computer model to plan the orbital path of
the satellite. Computer models are very often used to predict and understand how objects move
in outer space.
60. The purposes of science investigations include knowing something about the natural world,
as opposed to developing technology or creating processes or products for human use. Three of
these questions deal with designing, building, or improving engines: That is the realm of
technology. One question asks about the theory behind engines.
Science, not technology, can be used to answer questions about how efficient an engine can be
in theory, while technology can be used to answer questions about how efficient an engine is in
practice.