This video shows how Earth's axial tilt causes sunlight to reach the Northern and Southern Hemispheres differently, depending on the time of year.
It also discusses long-range changes in the tilt of the Earth (Milankovich cycles) that can affect Earth's climate and the differences in the amount of energy or heat available in the atmosphere during different times of the year in different locations.
Teaching Tips
Positives
The video illustrates the positional relationship between the Sun and the Earth from a variety of viewpoints.
A full transcript of the video is available.
Additional Prerequisites
This is one of a series of videos about the orbit and tilt of the Earth.
There is a season simulator that students can watch and pause to see animated graphs and images to help students visualize the changes.
Differentiation
Earth science classes could work in groups to make a diagram, a computer simulation, or a three-dimensional model of the Sun and the Earth to show how sunlight reaches different parts of the Earth at different places in the Earth's orbit.
Physics classes could investigate why the atmosphere reflects some of the Sun's radiation and the connection between the angle of sunlight and the surface area on Earth receiving the Sun's radiation.
Biology classes could use this resource for lessons about global cycles, wind patterns, biomes, and the distribution of life on Earth.
Other resources on this topic include this interactive presentation on solar radiation in Earth's atmosphere, this Khan Academy video that explains how the oceans keep the Southern Hemisphere from experiencing more severe temperatures, and this interactive database on temperature anomalies.
Scientist Notes
This video resource dives into the true cause of Earth's seasons; its axial tilt, also called obliquity. Earth's tilt causes different amounts of daylight for the Northern and Southern hemispheres depending on where it is in its revolution around the Sun, causing seasons. This resource is recommended for teaching.
Standards
Next Generation Science Standards (NGSS)
ESS1: Earth's Place in the Universe
MS-ESS1-1 Develop and use a model of the Earth-sun-moon system to describe the cyclic patterns of lunar phases, eclipses of the sun and moon, and seasons.
HS-ESS1-4 Use mathematical or computational representations to predict the motion of orbiting objects in the solar system.
ESS2: Earth's Systems
MS-ESS2-6 Develop and use a model to describe how unequal heating and rotation of the Earth cause patterns of atmospheric and oceanic circulation that determine regional climates.
HS-ESS2-4 Use a model to describe how variations in the flow of energy into and out of Earth’s systems result in changes in climate.
