1. Think about why we have seasons.
Do you know why there are seasons? It’s because of the positions of the sun and the Earth. Look at the illustration "Seasons." You’re going to do a hands-on activity to see how seasons work!
2. Gather your materials.
Gather together all of the materials you’ll need: an orange, two toothpicks, a flashlight, and a permanent marker. Make sure you have space to move, and a family member to help.
3. Create your “Earth.”
Stick one toothpick in the top of the orange. That toothpick is the North Pole. Stick the other toothpick in the bottom of the orange. That toothpick is the South Pole. Use the permanent marker to draw a line around the middle of the orange. That line is the Equator. Then draw a dot halfway between the line and the top toothpick. The dot is a person living in the Northern Hemisphere, the part of the Earth that is north of the Equator. In this activity, imagine you live where the dot appears.
4. Investigate summer sunlight.
Now turn on the flashlight and turn off the lights. Have your family member hold the Earth for you. Shine the flashlight straight at the middle line, or Equator. Ask your family member to tilt the North Pole toothpick toward the light. Where does most of the light shine? On the dot and the top half of the orange. This is the position of the Earth in summer. How much daylight does the North Pole receive as the Earth rotates on its axis? It is daylight 24 hours during this season. How much sun does the South Pole receive? None. It is dark until spring.
5. Investigate winter sunlight.
Next, ask your family member to tilt the North Pole away from the light. Where does most of the light shine? It should shine on the bottom half of the orange. This is the Southern Hemisphere, the part of the Earth that is south of the Equator. This is the position of the Earth in winter. How much daylight does the North Pole receive as the Earth rotates on its axis? None. It is dark until spring. How much sun does the South Pole receive? It is daylight 24 hours during this season.
6. Investigate sunlight at the Equator.
Have you noticed how much light shines on the middle? The amount of light stays about the same all year round at the Equator. That means the days stay warm and about the same length all year long.
Why are there seasons?
Materials You Provide
- Black construction paper
- Polystyrene foam balls or round fruit
- Push pins
- Transparent tape
The resources are also available at the top of the page.
- Internet Access: Optional
- Tech Setup: 1 computer per classroom, Projector, Speakers
- Plug-Ins: Flash
Recommended Prior Activities
The changing position of the Earth’s tilt is the reason for the differences in temperature and length of daylight that distinguish the seasons. When the Northern Hemisphere of the Earth is leaning toward the sun, it receives direct sunlight. The warmth of direct rays causes spring and then summer in that part of the globe. When the Northern Hemisphere of the Earth is leaning away from the sun, it receives more indirect sunlight. The cooling effects of more indirect sunlight cause autumn and winter. Because of the Earth’s approximately 23.5º tilt, the seasons in the Northern and Southern Hemispheres are reversed, about six months apart from each other.
Term Part of Speech Definition Encyclopedic Entry acute angle Noun
angle measuring between 0 and 90 degrees.
slanting space between two lines that ultimately meet in a point.
autumnal equinox Noun
autumn day, usually around September 22, when day and night are of generally equal length.
an invisible line around which an object spins.
Encyclopedic Entry: axis Equator Noun
imaginary line around the Earth, another planet, or star running east-west, 0 degrees latitude.
Encyclopedic Entry: equator hemisphere Noun
half of a sphere, or ball-shaped object.
Encyclopedic Entry: hemisphere Northern Hemisphere Noun
half of the Earth between the North Pole and the Equator.
North Pole Noun
fixed point that, along with the South Pole, forms the axis on which the Earth spins.
Encyclopedic Entry: North Pole obtuse angle Noun
angle measuring more than 90 degrees, but less than 180 degrees.
path of one object around a more massive object.
period of the year distinguished by special climatic conditions.
Encyclopedic Entry: season solar radiation Noun
light and heat from the sun.
Southern Hemisphere Noun
half of the Earth between the South Pole and the Equator.
South Pole Noun
fixed point that, along with the North Pole, forms the axis on which the Earth spins.
Encyclopedic Entry: South Pole summer solstice Noun
day of the year with the most hours of sunlight, June 20 or 21 in the Northern Hemisphere and December 21 or 22 in the Southern Hemisphere.
degree of hotness or coldness measured by a thermometer with a numerical scale.
Encyclopedic Entry: temperature tilt Verb
to lean or slant.
vernal equinox Noun
day, usually around March 21, when day and night are of generally equal length. Also called the spring equinox.
winter solstice Noun
(December 22 in the Northern Hemisphere, June 22 in the Southern Hemisphere) longest night of the year and the beginning of winter.