Tuesday, September 22, 2020 at 13:30 UTC (which is the same as 9:30 am EST), will be the Autumnal Equinox. It is the time of year when the imaginary plane that passes through the Earth's Equator would also travel through the center of the Sun. At this auspicious moment the number of sunlight hours and night time hours are about the same over much of the Earth. In the Northern Hemisphere we move into the Fall season.

Below is an Ecliptic animation from The Magic of Physics site. Below is a screen shot of the applet. By clicking on the link, a new window will open and students, or the teacher using a projector, can change the position of the person on the globe and other variables to enjoy a discussion of this auspicious moment.

Seasons_and_Ecliptic_Simulator

We have three possible activities for you to use in your classrooms after playing with the Nebraska applet.

- Autumnal Equinox-chart2020.pdf - What can you deduce about the Autumnal Equinox from this line graph?

For members we have supplied some of our thoughts: Autumnal Equinox-chart2020-thoughts.pdf

- Autumnal-Equinox-3-latitudes2020.pdf - How are the daylight hours of these three latitudes different and the same?

For members we have supplied some of our thoughts: Autumnal-Equinox-3-latitudes2020-thoughts.pdf

- Autumnal-Equinox-using-trig2020.pdf - Calculate daylight hours for any latitude with a formula involving trigonometry.

For members we also have our spreadsheet and charts: daylight-hours-N40.xlsx

CCSS: 5.G.A.2, 7.G.A.3, 8.SP, HSF.IF.B, HSG.MG.A.1, MP3, MP4