Lesson 3: Sun

• Students will learn the sun’s effects on plants and animals.

The sun is the largest object in the solar system. It contains more than 99.8 percent of the total mass of the solar system.

The sun is a star located at the center of our universe. There are many more stars in our galaxy. The sun is the closest at 150,000,000 kilometers (93 million mi) from Earth.

The sun is a huge, spinning ball of hot gas and nuclear reactions that lights up Earth, provides us with heat, and provides plants with energy to grow. At present, the sun is about 70 percent hydrogen and 28 percent helium by mass. Everything else amounts to less than 2 percent. This changes slowly over time as the sun converts hydrogen to helium in its core. Unlike Earth, it is void of any solid surfaces.

• Notebooks
• Paper
• Worksheet 1 - Grandmother Spider

(Only necessary for Alternative activities)

Have nine students read How Grandmother Spider Stole the Sun, a Native American legend about the sun that appears on Worksheet 1 under Resources.

Teacher reads: Stories like these have been told throughout history in nearly every ancient culture. (Discuss any stories the children might have learned from their parents and grandparents about the sun.) The sun has been a source of wonder and power to all people on Earth. It is important to know the effects of the sun on our environment. Today we will do this through observations.

Take students to an area where they can view both sun and shade. (This can also be done at different times of day or on a cloudy day, then a sunny one.) Ask students to record anything related to sun or shade that they see in their notebooks. They should especially observe animal behavior and plant differences.

After the observation time, allow students to share some of their observations. Have each student choose one observation and draw a picture of what they saw. Place these around the room. Have students group them by sunny observations and shady observations.

Stand by each group of pictures and discuss ideas about the sun’s power and its affect on plants and animals.

1. What does the sun do?
2. How does it affect plants and animals?
3. How the world would change if there were no sun for a week, month, year, 10 years?
4. Discuss the students’ ideas about the single most important element in the universe. (Some may say the sun, water, etc.) Have them explain why they think so.

1. Birds at a Food Table

Set up two areas with the same amount and kind of food. Place one of these in a shady spot and one in a very sunny spot (not too close together). Observe what happens to the food. Birds or other animals may come along. Observe their behavior as well. Have the students draw an image from the observation in their notebooks. Discuss the differences between the two areas. How were they the same and different?

2. Build a Sundial

Materials you will need:

• stick

• rocks

• watch or clock

Using your watch throughout the daylight hours, place a rock to mark where the shadow of the sun falls at that hour. Since a sundial can only show daylight hours, you will have a rock for each hour there is sunlight. Depending on when you start making your sundial, you may have to place rocks over a couple of days to complete it.

Now your sundial is ready to use. When you want to tell the time, just look for the shadow. In the image, the stones are used to mark each hour from 7 a.m. to 7 p.m. The picture was taken at 9:15 in the morning.

In the beginning, you may find it hard to be very precise. With a bit of practice, you should be able to tell time to the nearest 15 minutes, and maybe even more accurately.