1. Write what you know about the sun and solar energy.
Write what you already know about the sun and solar energy in the “Know” column of the KWL Chart. Think about what type of celestial body the sun is, how it affects the Earth, how humans try to harness its power, and why humans need it. Then, write a list of questions in the “Want to Know” column. What do you wonder about the sun and solar energy? For example: Does the sun rotate? How does the sun affect our seasons? What are solar storms? You’ll learn about the sun and solar storms in this activity, and will return to the KWL Chart later to complete column 3.
2. Watch the video “Solar Storms.”
Watch the National Geographic Channel video “Solar Storms.” What tools are scientists using to predict solar storms? Scientists are creating computer models by mapping the sun’s magnetic fields, or electrical currents. Sunspots are regions of extremely strong magnetic field found on the sun’s surface. The average lifetime of a medium-sized sunspot grouping is about one solar rotation, or 27 days. Think about how you use technology in your daily life. Why are solar storms a threat to our high-tech lives? The electrical activity from the sun has the ability to interrupt electrical activity on Earth. What might some examples of that be? Think about how we use satellites, electronic devices, and electricity in general.
3. Complete the worksheet Sunspot Mapping Grid.
Go to the Solar and Heliospheric Observatory (SOHO) Movie Theater website. Select image type: MDI Continuum. Leave the Resolution at 512. Leave the Start and End Dates blank. Enter 20 for Latest n images. Then click search. This will give you near real-time data for the last 20 images taken. Select and identify at least one sunspot to track over 4 days. Click the step button to move through the images. What do you notice as you step through the images? You should notice that the sunspot or sunspot groups appear to be moving across the surface of the sun. Do you think the sunspot is moving? Why or why not? Try to observe your sunspot in relation to other sunspots you see. Notice that the sun is rotating. Click the step button again to move through the images a second time. Plot each point representing the sunspot or sunspot groups you have chosen on the worksheet Sunspot Mapping Grid.
4. Revisit the KWL Chart.
What new information did you learn from this investigation? Write it in column 3 of the KWL Chart.
5. Make a math connection.
How can you determine the period of rotation of an object with fixed features on its surface? (Rotation can be determined by tracking the fixed features for a number of days.) Read through the directions on the worksheet Calculate the Sun’s Rotation. Then complete the worksheet.
6. Consider reasons for apparent motion of sunspots.
Sunspots appear to move across the face of the sun over time. Read the list of possible reasons below. Which reason do you think might be responsible for that apparent motion?
- Sunspots move across a non-rotating sun.
- The sun rotates.
- The Earth moves around the sun, causing sunspots to appear to move.
- Sunspots appear and disappear in different places, appearing to move.
(The correct answer is that the sun rotates. The sunspots stay reasonably stable as they appear to travel across the sun's surface. Sunspots seem to disappear on the righthand side of the sun, then reappear on the lefthand side. Sunspots keep a similar shape and stay at the same latitude and move at a constant rate at the same longitudes. The sun has a faster rate of rotation at its equator of about 25 days and a slower rate of rotation at the poles of about 36 days.) What are some possible ways to prove this explanation is correct? (Watch to see if some sunspots move faster than others at the same latitude. Follow sunspots to see if they change latitude as they change longitude. Follow sunspots to see if they move at the same rate and keep a similar shape and stay at the same latitude. Track how far the sunspots appear to move each day. See if they move at a consistent rate or if the rate changes. Pay attention to where the sunspots seem to appear or disappear. Watch for a pattern.)
Materials You Provide
The resources are also available at the top of the page.
The sun is responsible for all life on Earth; it gives us light and heat. The sun is not a solid body; it is a giant ball of gas made mostly of hydrogen and helium. Energy is produced deep within its core by means of nuclear fusion. Because of the sun's relative proximity to Earth, astronomers can gain important knowledge about other stars by studying our sun. It is the only star close enough to display a corona and a visible surface, which allows for observation of sunspot and solar activity. The sun does not rotate as a solid body because of its gaseous composition. The period of rotation varies from 25 to 35 days depending on the latitude (it is a shorter period at the equator). The surface of the sun is called the photosphere. Sunspots are cooler regions on the sun. They can be very large and are caused by the sun's magnetic field. Sunspots occur where the sun's magnetic field loops up out of the solar surface and cools it slightly, making that section less bright. Complex sunspot groups cause the eruptions of solar flares and can appear to be spectacular loops and prominences.
Term Part of Speech Definition Encyclopedic Entry heliosphere Noun
large region around the sun affected by the sun's magnetic field and the solar wind.
distance north or south of the Equator, measured in degrees.
Encyclopedic Entry: latitude longitude Noun
distance east or west of the prime meridian, measured in degrees.
Encyclopedic Entry: longitude magnetic field Noun
area around and affected by a magnet or charged particle.
magnetic storm Noun
interaction between the Earth's atmosphere and charged particles from solar wind.
lowest visible layer of a star and the boundary from which the star's diameter is measured.
solar flare Noun
explosion in the sun's atmosphere, which releases a burst of energy and charged particles into the solar system.
solar prominence Noun
huge eruption of cool gases from the surface of the sun, often shaped like a giant loop.
solar rotation Noun
movement of the sun around its axisthe time is variable, but about once every 27 days.
solar storm Noun
sudden change in the Earth's magnetosphere, caused by the solar wind interacting with the Earth's magnetic field. Also called a geomagnetic storm.
dark, cooler area on the surface of the sun that can move, change, and disappear over time.
For Further Exploration
- Solar and Heliospheric Observatory (SOHO): Real Time GIF Movies
- NASA: Living with a Star—The Sun-Earth Connection
- National Solar Observatory
- National Geographic Education: Article—How’s the Weather Up There?
- High Altitude Observatory (HAO): Questions and Answers About the Sun
- NASA: Solar and Heliospheric Observatory (SOHO)
- Stanford Solar Center