Moment of Science: Reasons for the Seasons

by Discovery Cube – January 9, 2018

Earth’s seasons do more than help us tell time or determine which fruits and vegetables will be available at the local grocery market. The changes that come with each season are a result of Earth’s tilt. Instead of standing straight up and down, the Earth leans slightly on its axis.

The axis is an imaginary line that helps Earth move around the Sun. It takes 365 days, or an entire year, for the Earth to make a full trip around the Sun. Depending on where Earth is on its journey around the Sun, our exposure to sunlight changes. This means different places in the world experience the seasons at different times.

Earth has four seasons throughout the year: winter, spring, summer, and autumn. Summer happens when the Northern hemisphere, or the part of planet we are on in Southern California, is tilted toward the Sun. The hemisphere tilted towards the Sun has warmer, longer days and shorter nights because the Earth is receiving more sunlight. When a hemisphere is tilted away from the Sun, it is winter. During this time of year, the days are colder and shorter because the Earth receives less sunlight. But when the Earth is partially tilted toward the Sun and partially not, we experience spring and autumn. Both “in-between” seasons are a bit warm and a bit cold.

Each season brings different changes to the Earth, impacting how we go about our day. Most importantly, seasons help many ecosystems stay in balance. So next time you go outside, take in the beauty of the season before it changes.

Materials: Leaf Rubbings 

  • White Copy Paper
  • Crayons
  • Leaves


Step 1: Collect leaves ranging in size and shape

Step 2:  Select one leaf and place the bottom/underside of the leaf face up

Step 3: Place the sheet of paper over the leaf and start rubbing the side of a crayon on the piece of paper

Step 4: Continue rubbing on paper until you have rubbed over the entire leaf

Step 5: Repeat Step 3 and Step 4 using different colors and other leaves

Step 6: Compare and contrast your rubbings – How are the leaves similar? How are they different? (Look at their shapes, sizes, and colors or feel their textures) How might these leaf rubbings compare to leaves you find during another season from the same tree or plant?