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7th Grade Semester Exam Review Answers
Thinking like a Scientist
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1. Define: Hypothesis, scientific inquiry, empirical evidence
Hypothesis – An educated guess or prediction based on the scientist's previous research
and background knowledge.
Scientific Inquiry – When a scientist performs experiments and investigations, using
various methods and tools, to discover information about the natural world, rather than
finding the answer in a book or getting told answers. Scientific Inquiry is more handson.
Empirical Evidence – The cumulative valid observations of the scientific community.
Try to link empirical evidence and observations together to remember this term.
2. Define:
a. Independent Variable – the variable you are testing. It is the variable that the
researcher changes. Also called the manipulated variable.
b. Dependent Variable– the variable that you are measuring. It is also called the
responding variable.
3. How many variables should be tested during an experiment?
Since the question is asking about the variable that is being tested, which is the
independent variable, the answer should be one. If there was more than one than you do
not know which of the variables caused the results to turn out the way that they did.
4. Why is accurate record keeping necessary during a scientific investigation?
So that someone else can replicate your experiment and therefore validate it.
5. If your conclusion does not support your hypothesis what should you do?
You can modify your experiment and retest another variation of your hypothesis.
6. Explain the difference between qualitative and quantitative observations.
Qualitative- Uses WORDS to make the observation.
Quantitative – Uses NUMBERS to make the observation.
7th Grade Semester Exam Review Answers
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7. In order, list the steps a scientist preforms during a scientific investigation:
Ask questions
Research
Hypothesize and predict
Test hypothesis
Analyze results
Draw conclusions
Communicate results
8. What is a biologist: Someone who studies life and living organisms.
9. Compare quantitative and qualitative observations See #6
10. How might scientists resolve their differences about scientific ideas, avoid bias, and
change scientific ideas? Debate their ideas at a scientific conference.
11. Define:
a. Replication
b. Repetition
Replication – When someone else does your experiment (better than repetition)
Repetition – When you repeat your own experiment
12. Differentiate between replication and repetition. See #11
13. Where during a Scientific Investigation will there be repetition? The amount of trials
14. How could one replicate an experiment?
Have someone else conduct your experiment by following the exact same procedures
that you followed.
15. List 5 results of Science. SKIP
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16. What is a model? A 3-D representation
17. How do models benefit a scientific investigation? Models can be used to explain things
that are too small, too large, too costly, or too dangerous.
7th Grade Semester Exam Review Answers
18. How do models limit a scientific investigation? Models are not exactly the same as the
thing that they are trying to represent so there will be limitations such as a model of the
solar system not being able to show gravitational forces.
19. Explain why all knowledge isn’t gained from scientific experimentations. Only one
variable is being tested during the experiment, and results aren’t always accurate. Also,
not everything can be tested.
20. Define:
a. Scientific Theory - Describes why or how a phenomenon in nature occurs
a. Scientific Law - Explains what or a relationship, or a pattern of nature.
21. How are scientific theories formed? Scientist’s debate with each other after enough
empirical evidence has been gathered that supports the theory.
22. How are scientific theories different from laws? See number 20.
23. Can scientific theories be modified, rejected or both? Justify. Both - when new evidence
that contradicts the theory arises, the theory is usually modified and in rare cases can be
rejected.
24. Can a scientific law be modified, rejected, or both? Justify. Same as #23
25. Give an example of a two Scientific Laws that you learned about this semester.
a. Identify the pattern in the law. Answers vary, but there are mathematical
equations for many laws that are always true and therefore show patterns in
nature.
26. Give an example of a Scientific Theory you learned about this semester.
a. Why is the theory able to be modified? Answers vary, but you were shown how
cell theory was modified throughout time as new evidence and ideas arose.
7th Grade Semester Exam Review Answers
Energy
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27. Using the diagram to determine if the change of
state would require adding heat or removing heat?
Melting- Add Heat
Freezing- Remove Heat
Evaporation- Add Heat
Condensation- Remove Heat
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28. Define:
a. Potential energy – stored energy, or energy due to position
b. Kinetic energy – energy of movement
c. Work – Equals Force times Distance. If it doesn't move, then in science, no work
has been done.
d. Energy – The ability to do work or cause change.
e. Insulator – Heat cannot pass through it very well. You put insulation in your walls
to keep heat or cold from escaping. People use styrofoam to keep their coffee hot.
f. Conductor – Heat can pass through it well. Metal is a good conductor. Notice that
metal feels cold because it is quickly taking heat away from you.
29. Explain the relationship between energy and work Energy is the ability to do work.
30. Differentiate between potential energy and kinetic energy. See 28a and 28b
31. List the forms of energy. MR. SCENT – Mechanical, Radiant, Sound, Chemical, Electrical,
Nuclear, and Thermal.
32. What does the Law of Conservation of energy state? That energy cannot be created or
destroyed, but can only transform into other types of energy.
33. How does the Law of Conservation of Energy relate to Energy being transformed or
transferred? Energy can be transformed or transferred.
7th Grade Semester Exam Review Answers
34. List the different ways Thermal energy is
transferred. Conduction, Convection, and Radiation
35. Describe the different ways thermal energy is
transferred. Conduction – Transfer of heat through
direct contact.
Convection – The movement of the particles themselves. Hot air rises, cold air sinks.
Radiation – Heating through light energy (electromagnetic spectrum)
36. Give an example of:
g. Conduction - A pot touching a hot stove
h. Convection - The hot water in a pot rising and the cooler water sinking.
i. Radiation - The sun warming the Earth's surface.
37. Manufacturers place rubber handles on metal cooking pans. Explain why the rubber
handles are needed using the terms insulator and conductor. The metal is a good
conductor so it would transfer heat to your hand quickly so a rubber handle is used
because it is a good insulator so your hand will not get burned.
38. Describe the energy transfer between objects of different temperatures. Heat travels from
hot to cold until both objects reach the same temperature.
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39. What source of energy comes from the Sun?
Radiant energy, Electromagnetic Waves, or Light Energy
40. How does the sun’s (radiation) energy travel? Through transverse waves.
41. What is the name for the waves that carry the sun’s energy radiation? Transverse waves
42. List the Electromagnetic Waves in order from lowest frequency to highest frequency.
Radio Waves, Microwaves, Infrared Radiation, Visible Light, Ultraviolet, X-rays, Gamma Rays
43. Explain the relationship between the frequency, wavelength and energy of a wave.
Higher Energy = Higher Frequency = Shorter Wavelength
Lower Energy = Lower Frequency = Longer Wavelength
7th Grade Semester Exam Review Answers
44. Draw two waves of the same distance with different wavelengths.
45.
Compare the wavelengths using the terms energy, frequency, and wavelength. See #42 and 43
46. Are light waves the same or different from EM waves? The same
47. Can light waves travel through matter, vacuums, or both? Both, an object might block
visible light from passing through, but remember that light waves include radio waves
through gamma rays as well.
48. Can sound waves travel through matter, vacuums, or both? Only matter, since sound
requires particles to make direct contact with each other to transfer sound.
49. Which of the light waves (EM waves) is visible with your eyes? Visible Light
50. List the different colors of light in order from shortest wavelength to longest wavelength.
ROY G. BIV – Red, Orange, Yellow, Green, Blue, Indigo, Violet
51. List the different colors of light in order from lowest frequency to highest frequency.
See #50
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52. Describe light:
a. Reflection
b. refraction c. absorption
a. Reflection – light bounces off at the same angle it came
towards the object
b. Refraction – light bends when it goes through matter of
different densities, such as from air to water.
c. Absorption – Light gets absorbed into the object.
53. Give an example of light:
a. Reflection b. refraction
a. Reflection – Mirror
c. absorption
b. Refraction – Spearing Fish
c. Absorption – An opaque object blocking light
7th Grade Semester Exam Review Answers
54. When light is shining on an object with blue color. What happens to the blue beam of light
in as hit touches the object? What happens to the remaining colors? All the colors are
getting absorbed by the object except for blue. The blue color is being reflected and taken
in by your eyes so you end up seeing the object as blue.
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55. Do light waves, sound waves, and other
waves travel the same speed in different
materials? Justify. No, light waves travel
fastest in a vacuum, such as space. Sound
waves travel fastest in a solid and slowest in
air.
Changing Surface of the Earth
Layers of the Earth
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56. List the layers of the earth.
Physical layers – Crust, Mantle, Core
Chemical layers – Lithosphere, Asthenosphere, Mesosphere, Outer Core, Inner Core
57. What is the outermost layer of the Earth?
Crust or Lithosphere
58. Where in the Earth’s layer are there convection currents?
In the Asthenosphere
59. Describe convection currents.
Hotter magma (less dense) rises and cooler magma (more dense) sinks and forms a convecting
current, where magma is in motion. This is the cause of continental drift.
60. Which two parts of the Earth make-up the lithosphere?
The crust and the uppermost mantle made up of brittle mantle (not yet a semi-solid).
61. This layer of the Earth is a semisolid.
Asthenosphere
62. Explain the characteristics of a semisolid.
Semisolid is called “plastic” and is slow moving.
63. List the layers that are solid.
Inner Core, Mesosphere, Lithosphere
7th Grade Semester Exam Review Answers
64. Identify the:
a. Outermost layer- Crust
b. Innermost layer- Inner Core
c. Liquid Layer- Outer Core
d. Thinnest layer- Crust
e. Thickest layer- Mantle at 1800 miles thick (the inner core is the densest)
f.
Layer where convection currents are- Asthenosphere
Rock Formation & Rock Cycle
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65. Describe the formation of the rocks.
a. Igneous - Formed from cooled magma (in the ground) or cooled lava (above the ground)
b. Metamorphic– Formed from heat and pressure inside the Earth.
c. Sedimentary – Formed from compaction and cementation.
66. Draw a diagram of the Rock cycle.
67. Explain how all rocks are connected in the rock cycle. All rocks can eventually get changed into
each other over millions of years.
68. Identify agents of erosion. Things that can move objects, such as wind and water, and also people
and animals.
7th Grade Semester Exam Review Answers
69. Differentiate between physical & chemical weathering.
Physical weathering breaks things down (ripping paper, breaking up rock). Chemical weathering
changes the objects nature or chemical make-up (burning paper, iron to rust)
70. Use the terms weathering, sediments, and deposition in a sentence to explain the principle or
horizontality. Rocks get broken down into sediment and are deposited horizontally on Earth’s
surface.
71. Describe what happen to the earth’s surface when it is affected by weathering and erosion.
The earth’s surface changes.
Plate Tectonics
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72. Describe Plate Tectonics - The Earth’s surface is made up of 12 large plates that move due to
convection currents in the Asthenosphere. This causes continents to change location over millions
of years.
73. Explain Pangaea. When all of the continents were together to form a super continent.
74. Which layers of the Earth make up the lithosphere?
The crust and the uppermost, brittle mantle.
75. Which layer of the Earth allows the lithosphere to float and hold?
Asthenosphere
76. Explain how the asthenosphere being a semisolid allows the lithosphere
to both float and hold. The Lithosphere is less dense than the
Asthenosphere so it floats on top of the Asthenosphere. The
Asthenosphere semi-solid nature (slow-moving “plastic”) keeps the
continents from moving too quickly
77. Identify the motion at the following boundaries:
a. Convergent
b. Divergent
c. Transform
a. Convergent – plates move towards each other
b. Divergent – plates move away from each other
c. Transform – plates move along-side each other
7th Grade Semester Exam Review Answers
78. Identify the major surface & subsurface events that take place at the following boundaries:
b. Convergent
b. Divergent
c. Transform
a. Convergent – Mountains, Volcanoes (when subduction occurs)
b. Divergent – Trenches (the Mid-Atlantic Ridge (seafloor spreading) is formed from divergent
plates), Volcanoes (many are below the ocean)
c. Transform – Earthquakes, fault-block mountains
79. What are the primary forces that cause continents to move? Where are the forces located?
Convection Currents in the Asthenosphere.
80. Explain how mountains, earthquakes, seafloor spreading, and volcanoes are formed. See #78
81. What are subduction zones? When one plate submerges under another plate (causes volcanoes)
Geologic Time
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82. Explain the following principles:
a. Principle of Superposition – The lower the rocker layer, the older it is.
b. Principle of Horizontality – sediment is originally deposited horizontally
c. Principle of Cross-Cutting – A feature that cuts through rock layers is younger than
the rock layers that it passes through. For example, magma shooting through rock
layers.
d. Principle of Inclusion – Inclusions (rock found in other rock) are older than the rock
they are found in. For example, a piece of rock falls in magma that later cools.
83. List the periods in the correct sequence of geologic time. (past to present)
Cambrian, Ordovician, Silurian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, Tertiary
84. What evidences did scientist use to create the geologic time scale?
Relative Dating (ex. principle of superposition) and Absolute Dating (ex. radioactive dating)
7th Grade Semester Exam Review Answers
85. Define the terms below:
a. Absolute Dating
b. Relative Dating
a. Absolute Dating – Age written in years. Can be found using radioactive dating
b. Relative Dating – Age said as “older than” or “younger than”. Can be found using the
principles of superposition, crosscutting, original horizontality and inclusion.
86. Differentiate between absolute dating and relative dating. See #85
87. How would things be different without absolute dating?
Scientists may not realize that the Earth is billions of years old.
Humans Impact on Earth
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88. Define:
a. Deforestation- The removal of large areas of forest for human purpose.
b. Desertification- The development of desert-like conditions due to human activities,
and/or climate change.
c. Overgrazing- Allow animals (such as cows, horses, and goats) to eat so heavily that the
vegetation is damaged and the ground becomes liable to erosion.
d. Urban Sprawl- The development of land for houses and other buildings near a city.
89. How do these following events affect the Earth?
90. Explain how human activities such as urban sprawl, deforestation, and desertification affect the
landscape of the Earth.