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Small Moon, Big Sun 1

This is a 4-H Solar Eclipse activity by Cynthia Canan, PhD, State 4-H STEM Specialist, Ohio State University Extension,  Sara Newsome, 4-H Alumnus and STEM Student Assistant, The Ohio State University, and Rhonda Williams, Editorial Specialist, Ohio State University Extension Publishing
Reviewed by: Wayne Schlingman, PhD, Director of the Arne Slettebak Planetarium, The Ohio State University, Danielle Combs, Extension Educator, 4-H Youth Development-Highland County, Ohio State University Extension and Christy Millhouse, Ohio 4-H STEM Educator, 4-H Youth Development, Ohio State University Extension

Topic: Space Science | Estimated time: 30-45 minutes | For groups (Cloverbud, K-2) Group Size: 6-8 children per adult volunteer. | PDF for PRINTINGThe moon covers the sun during a total eclipse.

A total solar eclipse is a rare and awe-inspiring astronomical event that occurs when the moon completely covers the sun, temporarily blocking out its light. As total darkness consumes the path of totality, the temperature could drop, stars and planets could become visible, and animals could behave as if it were nighttime. But we know the moon is smaller than the sun, so how does the moon cover the sun?

BACKGROUND

A total solar eclipse occurs when the moon completely covers the sun, temporarily blocking out light. We know the moon is much smaller than the sun. In fact, the moon is about 400 times smaller than the sun. This means if the sun were the size of a basketball, the moon would be about the size of a pinprick, or a single dot made by a sharp pencil. How can such a small moon cover the big sun during an eclipse? The answer is in the distance between Earth and the sun and Earth and the moon.

When we look at an everyday item and hold it closer to our eyes, it will appear bigger compared to the same item held farther away from our eyes. The same phenomenon occurs when we observe the things in the sky from Earth: an object closer to Earth will appear to be bigger compared to the same object farther away from Earth. Even though the moon is 400 times smaller than the sun, it is also about 400 times closer to Earth compared to the sun. Because of these similar ratios in distance and size, the moon and the sun actually appear similar in size when we observe the sky from Earth. This is why, when the moon moves in front of the sun, the moon can cover the sun completely.


GETTING STARTED

What is an eclipse?

Materials

  • Write the word "Eclipse" on a piece of paper or poster so the children can see it, spell it, and sound it out.

What To Do

Lead a discussion about the planets and the solar system. Explain that the solar system is a collection of objects which rotates around the sun. Start the discussion by asking these questions:

  • What are the names of things found in our solar system? (sun, stars, moon, asteroids, comets, planets—Earth, Mars, Jupiter, Saturn, Uranus, Venus, Mercury, Neptune)
  • What is the name of the planet where we live? (Earth)
  • What is the name of the yellow star that shines in the sky? (Sun)
  • What is the name of the white object (not the stars) we see in the sky at night? (Moon)

Explain that a solar eclipse occurs when the sun, Earth, and moon are in a line and the moon covers the sun. Depending on where you live, you may see a partial eclipse or a total eclipse. During a partial eclipse, the moon only covers part of the sun. During a total eclipse, the moon completely covers the sun. Show the children the image of the aligned sun, Earth, and moon to help them understand.

The moon between the sun and Earth casts a shadow on the Earth.

Application

Ask the children if they think we could live without the sun. Why or why not?


DIGGING DEEPER

Understanding the Solar Eclipse

Materials

  • Coins (penny, nickel, dime, quarter), masking tape, paper plate, crayons or markers (optional)
  • Chart (one copy)

Be sure to complete this activity in a long space, such as a hallway or gym.

What To Do

Begin by explaining that a total solar eclipse is a rare and awe-inspiring astronomical event. A total solar eclipse occurs when the moon completely covers the sun, temporarily blocking out its light. As total darkness consumes the path of totality, the temperature could drop, stars and planets could become visible, and animals could behave as if it were nighttime. But we know the moon is smaller than the sun, so how does the moon cover the sun? This activity will help children understand what happens during the solar eclipse. You might need to demonstrate each step to your group.

Tape a paper plate to a wall. Have the children color the plate so it looks like a sun or write the word “sun” on it. Ask a child to stand in front of the plate. Give a child a penny, and then direct the child to stretch to hold the penny in front of the plate. Tell the child to close one eye and look at the penny with the plate behind it. The child should begin taking steps backward while holding the coin. Tell the child to stop when the penny appears to be the same size as the paper plate (covers the entire plate when they line up the coin and the plate). Use masking tape to mark the ground where the backs of the child’s feet stopped.

Compared to the distance walked for the penny to cover the plate, do the children think they will have to walk closer or farther away with the other three coins to eclipse the sun? Fill in the chart with their predictions. Ask them how to explain why they made each prediction. Have the children check their predictions by experimenting with the other coins. Record their results on a copy of the chart.

A chart with nickel, dime, and quarter rows and Prediction and Experiment Results columns.

Application

How did the size of the coin change the number of steps they had to take?


LOOKING WITHIN

Materials

  • Tablet or laptop with Internet connectivity

What To Do

Watch “Why Doesn’t the Moon Fall Down?” and learn how gravity keeps the moon in an orbit around Earth.
go.osu.edu/gravityandthemoon

Application

Ask the children what they think would happen if there were no gravity.


GOING BEYOND

What the Solar System Looks Like

Materials

What To Do

Have each child color the picture of the solar system.

Application

Ask the children what they think it would be like to travel to other planets.


READING ADVENTURES

These books are great for sharing. Consider using one to provide background, to set the stage before the lesson, or to reinforce the lesson. Check your local library for additional materials.
The Sun is Kind of a Big Deal by Nick Seluk
Eclipse by Andy Rash
Eclipse by Darcy Patterson

Book covers: The Sun is Kind of a Big Deal; Eclipse; and Eclipse


Vocabulary

astronomical. Relating to the study of objects outside earth’s atmosphere.

path of totality. The path of the moon’s shadow across Earth’s surface.

phenomenon. An observable fact or event of scientific interest

prediction. The use of evidence to decide what will happen next.

ratio. A number that shows the relationship between two amounts.

total solar eclipse. An astronomical event that occurs when the moon completely covers the sun, temporarily blocking out its light.


SOURCES

“How Is the Sun Completely Blocked in an Eclipse?” NASA Science Space Place. spaceplace.nasa.gov/total-solar-eclipse/en
“Eclipse: How can the little Moon hide the giant Sun?” NASA Sun-Earth Day. sunearthday.nasa.gov/2007/materials/eclipse_smallmoon_bigsun.pdf

LEARNING OUTCOMES

Project skill: Understanding how size and distance affect the appearance of the Earth, moon, and sun | Life skill: Decision making | Educational standard: NGSS 1-ESS1-1. Use observations of the sun, moon, and stars to describe patterns that can be predicted. | Success indicator: Predicts and records data about distance and the sizes of objects

For more solar eclipse activities, visit go.osu.edu/4hsolareclipse.