Age:5-8
Subject:Science
Skill:Predicting analyzing, observing, measuring
Time:Variable
Group Size:Any
Setting:In/Outdoors

The green links are vocabulary words. Click on the link to read the definition.

Objective: You will be able to state how cold temperatures affect the world around you.

Background: The earth makes two kinds of major movements, rotation and revolution. The earth rotates around the imaginary line called the axis. The northern end of the axis is the North Pole, and the southern end is the South Pole. The earth rotates once everyday-24 hours- around the axis. The rotating earth travels about 1,000 miles per hour (1,609km/hr)! (Don’t forget that you are traveling along on this 1,000 mile-an-hour journey)

The rotating earth also revolves around the sun. It takes the earth one year- 365 days- to complete its journey around the sun. The earth speeds along at 64,000 miles an hour (102,995km/hr) for its revolution. (You are still on this journey, right? Traveling at 64,000 miles an hour through space while simultaneously rotating at 1,000 miles per hour.)

As the year progresses and the earth revolves around the sun, the tilt of the earth’s axis doesn’t change. The axis is 23 ½ degrees away from a straight up and down line relative to the sun’s position. This means that for some of the year, the North Pole is aimed toward the sun, and some of the year it is aimed away from the sun.

When the North Pole is aimed toward the sun, Alaska receives more concentrated light and heat. This is Alaska's summer. Winter is the season when the North Pole

is aimed away from the sun. If the earth were not tipped this way, the Arctic would receive the same amount of sun all year long, like the equator.

Materials: Bright flashlight; commercial sun-earth rotation model, or a create-your-own model from a moveable lamp (without a lampshade) or flashlight, an orange or a styrofoam ball with a pencil stuck through the center like an axis and the Arctic Circle and Alaska drawn on its surface.

Procedure: Set up the sun-earth model in the center of a room.

3. You will be simulating the rotation of the earth first. Spin in place (slowly!). This action is called revolution or revolving.

5. Now both rotate and revolve around the room. Then dim the light in the room. Have someone stand in the center of the circle. Next, the person in the middle of the circle should shine a strong light on you so that you can experience a sunlight exposure as you revolve and rotate. Remember not to shine the light directly in anyone's eyes. Stop revolving and rotating when you get back to where you started from.

6. Sit around the sun-earth model. Shine the light on the "globe". Locate Alaska on your "globe". 

 

7. Hold your "globe" so the axis is straight up and down. Revolve and rotate your "globe" around the sun. Does the amount of light shining on Alaska change? Now tilt the "globe" so the axis is slanted or at an angle. Keep the "globe" tilted and make the "globe" rotate. It is important that you keep the tilt the same all the time.

8. Find Alaska again on your "globe". Keep the globe slanted and rotate and revolve the "globe" around the sun. Does Alaska get the same amount of sun all  the way around the sun? Or does it get a lot of sun sometimes and very little sunlight at other times.  How does the amount of solar energy, sunlight, that reaches Alaska changes as the earth revolves. Which season does the "globe" receive the most sunlight? 

9. Why are Alaska winters so cold? (Lack the sun’s energy). To figure this out you can do the experiment on the Absence of Heat.

Extension: Use your Ranger Notebook to find signs of cold in your environment.

Procedure: Make an observation chart. Observe the snow, plants, and animals around your home or nearby natural area. Make a chart that has three columns, like the one below. You can draw pictures instead of writing.

Name	Temperature	How does the cold affect it?
	22°F	The bear hibernates.
Snow	30°F	Snow is light and fluffy.
Willow Bush	33°F	The willow lost its leaves.
Pop bottle full of water	29°F	Water became ice and bottle burst.
Snow	-41°F	Snow is crunchy and dry.

3. Make a chart listing all the things you found that tell you it is cold. To make a conclusion to this investigation, draw a picture. The picture should include all of the things that you found that tell you it is cold.