This lesson is based on California's Middle School Integrated Model of NGSS.
MS-ESS1-1 Earth's Place in the Universe
PE: MS-ESS1-3 Analyze and Interpret data to determine scale properties of objects in the Solar System.
DCI: ESS1.B Earth and the Solar System - The Solar System consists of the Sun and a collection of objects including planets, their moons, and asteroids that are held in orbit around the Sun by its gravitational pull on them.
SEP: (2) Developing and Using Models - Develop a model to describe unobservable mechanisms. Using a lunar lollipop students will be able to see the mechanism that causes lunar eclipses.
CCC: (1) Patterns - Lunar eclipses are predictable phenomenon that can be easily conveyed to students and provide an opportunity for them to make and record direct observations of a lunar eclipse.
This lesson was written to satisfy a complaint I have teaching astronomy. I instruct students about the patterns in the night sky, but I do that in the daytime with models. At no time am I able to provide direct observable evidence for what I teach unless I get the kids outside looking up at the stars. Having the kids look up at the night sky without being able to ask questions is something I worry about creating a misconception. With this activity the science has been covered by me ahead of time, the students are just making observations
This lesson accompanies another lesson I do called Lunar Lollipops. All the student work and activities were completed during the Lunar Eclipse on April 2, 2015.
Lunar Eclipses occur because our Moon travels through the Earth'c shadow. This shadow, caused by the Sun, strikes the surface of the Moon. Lunar eclipses don't occur every time the Moon is on the far side of the Earth (New Moon position) because the Moon's orbit is slightly tilted by 5 degrees. Lunar eclipses happen about every eighteen months and are very predictable.
When compared to solar eclipses, lunar eclipses are a rarer phenomenon. However, due to the alignment almost everyone on the night half of the Earth can see a lunar eclipse, so it is viewed by a much larger population.
Before I have my students observe a lunar eclipse, I walk them through the mechanics of what is really happening. You first need a simulation of the Sun, Earth, and Moon.
To simulate the Sun I hang a 60w light build in the center of my room (see Lunar Lollipops) and cover all the windows. My goal is to have one light source (simulated Sun) in order to accurately depict shadows.
To simulate the Earth I use an ordinary Earth globe found in almost every classroom. If you don't have a globe a basketball could be a reasonable substitute.
To demonstrate a lunar eclipse position the Sun (lightbulb), Earth (globe), and Moon (lollipop) in direct alignment so that the shadow of the globe falls directly onto the surface of the lollipop.
It's beneficial for you to demonstrate movement by passing the Moon into the shadow. If you look closely you can actually see the curvature of Earth's shadow on the surface of the Moon.
At the height of the eclipse the Moon will turn a pale shade of red (called a Blood Moon). This occurs because some of the sunlight is filtered through the Earth's atmosphere into the color red. If you use my Lunar Lollipops activity I have my students create a lunar eclipse as a final step in the lab.
I typically announce that a Lunar Eclipse is nearing about two weeks in advance. This provides my students with the opportunity to talk with their parents and see if they would be allowed to stay-up and watch the eclipse. I also speak to the other teachers at my grade level and ask if they could limit their homework on that date. Eighth graders get pretty excited knowing that their teacher has assigned homework that causes them to stay up extra late.
As part of the event I encourage my students to take pictures of the Lunar Eclipse. I then compile these photos into a classroom video for everyone to watch.
Student Work Sample
As part of this assignment, each student must create a diagram explaining the geometry of a lunar eclipse in their Science Interactive Notebook. The diagram must include the Sun, Earth, and Moon, use the terms penumbra and umbra to describe the light and dark parts of the shadow, and use at least three colors.