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SUNSPOTS Test Answer Key
The following answers reflect
content contained in the Sunspots lesson. You may want to devise
your own grading rubric to facilitate scoring,
1. Why is the Sun important to life on Earth? Please list three ways the
Sun's light and heat helps us to live?
1. The Sun provides energy for plant
photosynthesis - the foundation
upon which other life forms depend. 2. Its light and heat make
Earth a temperate environment. 3. Its light and heat power wind
and weather systems which create water cycles.
2. Why did some ancient cultures observe and worship the Sun?
- Ancient cultures thought the Sun was a god since it had the power to provide
light, warmth, and the energy to make plants grow. They
attributed special god-like qualities to the Sun. The early
cultures wanted to understand the powerful sun and please it so its
life-giving gifts would continue, and to prevent "punishment"
in the form of droughts and flooding rains.
3. How did Europeans such as Galileo observe sunspots?
- At first Europeans used their eyes, and looked directly at
the Sun when there
was fog or at sunset, when the Sun was less bright. After the telescope was invented by the Dutch
in 1608, European astronomers such as Galileo used the telescope to
observe sunspots. Looking directly at the Sun can cause irreversible damage to
4. We should never look directly at the Sun. However, can you briefly describe a safe and easy way to observe
The 'projection method' is a good way to view the
Sun safely. Mount a telescope or pair of binoculars on a tripod, point it
toward the Sun, and place a flat white surface behind the eyepiece upon
which the image of the Sun can be projected. Never look directly through
the eyepiece to aim at the Sun, as that can cause severe eye
damage. A cardboard screen placed
around the telescope or binoculars, with a hole cut to
the outside diameter, will create a shadow
behind the apparatus which makes the projected image more visible.
in the 1600’s did not yet know what caused sunspots. What ideas, beliefs, and opinions did they have about them?
Many Europeans at that time believed that the
heavens were perfect or without irregularities, following the ideas of Aristotle. When
scientists first saw sunspots using telescopes they didn't know what they were.
Some, like Galileo, believed the spots were part of the Sun itself. This
belief caused an outrage among many people of the time since spots suggested
imperfection in the heavens. Scientists who sought to maintain the
older view thought the spots must be moons, clouds, or other planets
orbiting around the Sun. This model could be consistent with the doctrine
that the Sun was perfect and not flawed by spots.
Modern Research Section
6. In Galileo’s time (1564 – 1642) observers could only view the Sun
visible, or white light spectrum. Today, however, astronomers have very powerful telescopes which can observe
the Sun in great detail, and in other wavelengths of light. Name any two types of non-visible light these new instruments can
Modern telescopic equipment using various
filters and detectors can measure wavelengths in the non-visible light
portions of the electromagnetic spectrum. These new instruments can
detect: ultraviolet, infrared,
X-rays, and gamma rays.
7. List at least two facts about the Sun's mass,
composition, or structure.
- Possible Answers:
- The Sun
is the largest object in the
solar system, and contains 98% of the solar system's mass.
earths could fit across the Sun's diameter.
- The Sun
is made of about 90% hydrogen and 8% helium by mass, with other trace
- The Sun is composed of a core,
radiation zone, convection zone, photosphere, and corona.
- The Sun
is powered by nuclear fusion reactions in its
- he sun's surface temperature is about 5,800 K.
- Its outer corona is much hotter: about 1 - 2 million
- The Sun
has a strong magnetic field which is constantly changing.
8. How big is an average sunspot? (multiple choice question)
d. An average-sized sunspot is about the size of the Earth.
happens in the Sun’s convection layer? (multiple choice question)
e. a and d - heat is transported
to the surface by flows of hot plasma & cool plasma flows back toward
10. What is the source of sunspots' magnetic fields?
(multiple choice question)
b. moving currents of electrically charged particles.
11. Can you describe what happens during the Sunspot cycle? How long does it
take to complete a cycle?
- The number of sunspots at any time rises and falls in a
regular rhythm, cycling from low to high and back to low about every 11
years. Scientists now know that the Sun's magnetic field
changes direction every 11 years, to create a complete cycle in 22 years. Sunspots appear at high latitude early in the cycle, and
gradually appear closer and closer to the equator later in the cycle.
12. It has been speculated that the solar minimum affects the climate of the
earth. Can you name one famous, unusually cold period in history that
corresponds to low levels of solar activity?
- Oort Minimum (1010-1050)
- Wolf Minimum (1280-1340)
- Spörer Minimum (1420 -1530)
- The Maunder Minimum (1645-1715)
Note: These are all part of what is now called "The Little Ice Age"
- 13. How does
the Earth's magnetic field protect us?
- The Earth's magnetic field is continually protecting us by deflecting energetic, charged
particles and the magnetic field of the solar wind.. If it were not for
the earth's magnetic field, the charged particles would change the
ionosphere and destroy the ozone layer permitting high levels of harmful
UV radiation to reach Earth's surface.
14. What impact does space weather (geomagnetic storms) have on Earth?
f. all of the above - Satellites can be disabled or have their orbits
decay; auroras become more frequent and bright; power grids can be overloaded and cause power outages to cities and
homes; radio transmissions can be drowned out.
15. What is a sunspot? In the space below, please draw a picture of a sunspot, and label as many parts as you
can. Draw the magnetic field lines around the sunspot(s).
Pictorial representations could include:
- Photosphere: the Sun's visible surface, upon which sunspots
- Umbra: a dark, roughly circular central disk. The term
umbra means "shade" in Latin.
- Penumbra: a lighter outer area that surrounds the dark umbra at
- Magnetic field loops: arcs created when
push up through the surface, bringing some of the hot plasma with them.
Loops end on the sunspots on the Sun's surface.
- Flares, or blobs of ejecta from a CME.
- 16. How is a sunspot created? Describe
what happens in the Sun to produce a sunspot.
Convection currents create a dense magnetic field loop. Local magnetic pressure causes it to bow out
from the surface. Places where the magnetic field lines leave and
re-enter the Sun's surface appear as the dark sunspots we observe.
Inside the sunspot high magnetic pressure causes lower gas pressure.
This means the Sunspot is less dense, cooler, and darker than the surrounding
17. Many scientists and
astronomers study sunspots. Why is their research important?
Many answers are valid or partially correct
18. Please think about the activity you did in the
Activity Section (the Sunspot white light vs. x-ray active area measuring
and data plotting). What did your plot look like? Describe the pattern of points on your graph. As a science investigator, what do you think
this means about sunspots and x-ray active areas on the Sun?
Scientists do not yet know everything about the Sun
and how it
- Scientists study the Sun in order to learn about how
- Scientists want to know how the Sun effects our environment on
Earth; more specifically,
If we can learn to predict when powerful solar storms
will occur, it may show how to prevent damage to communication systems, power grids, satellites, and
danger to astronauts in space.
- Scientists do not yet know whether cycles of solar
activity may affect Earth's climate, which could potentially affect global warming and food supplies.
- Finally, when scientists answer one question through their research, they usually create
another question in the process!
Students should be able to describe the graph
using the correct terms for measured quantities. For example:
"In our graph x-ray active areas were plotted along the vertical axis
and sunspot areas along the horizontal axis. Most of the points fell
near a line with a positive (or negative, or flat, or vertical)
slope." If the slope seemed nearly flat or vertical,
students should note the constant value of x-ray area or sunspot area
(respectively) of the line. Students' descriptions of x-ray vs.
sunspot area graphs should not mention time dependency. Students should
understand that any well-defined systematic pattern in the graph is a sign
of some correlation. Only if the points seem randomly scattered would the
two quantities not be related. Any of these kinds of observations on the
part of the student show understanding of the
measurement/plotting/interpretation process. Better answers will have more
detailed descriptions and make a logical connection between the plot
description and interpretation of any correlation the plot does or does
area vs. time Give students an appropriate alternative
wording for question 18. Descriptions of these plots may
include observations about the shapes of the graph and whether graphs of
x-ray areas and sunspot areas look alike. Students making both time
graphs should try to draw some conclusion about whether similarity indicates