It would be almost impossible to explain Moon phases without pictures or, at the very least, waving your hands around.Both the Earth and the Moon are half lit on the side facing the Sun. The Earth rotates once every 24 hours and the Moon orbits the Earth every 28 days. The Earth only faces the Moon 12 hours a day so we get 28 distinct moon phases. Here’s a picture that will help visualize what’s going on.
Mouse over for captions
Keep in mind that the same side of the Moon always faces the Earth, like it was on a string. What you can also see from the graphic is:
• There is always a dark side of the Moon, as there is always a dark side of the Earth.
• There is a side of the Moon we never see, but it’s not always dark.
• How eclipses happen. A solar eclipse is the Moon’s shadow on the Earth and a lunar eclipse is the Earth’s shadow on the Moon.
We see moon phases because of the relative motion of the Earth and Moon and our perspective from the surface of the Earth. Changing the perspective is the easiest way to see what is happening. Here is a short narrated video that may help you to visualize the mechanics.
I’ve always wanted to try screen capture. To be able to see the software being used is a great teaching method. I demonstrate software in my labs using a projector but this doesn’t always work perfectly and it’s difficult to find the pace that works for everyone. With a screencast you can get one perfect recording and students can then digest the process asynchronously, at their own pace, able to pause and go back as needed.
Much the same way as a traditional book is better with pictures, a narrated video makes for a richer learning environment. Jon Udell (2006), InfoWorld technology columnist and accredited “screencasting” father says screencasting is an “effective user-centered educational method for learning rapidly how software, web services, and other computer-based applications work.”. Learning from a narrated video is an example of Dual Coding Theory (Thomas, 2014). In Dual Coding ,verbal memory and image memory are handled by separate areas in the human brain. Learners can use both areas simultaneously and in concert to process information. More generally, it has been well established that students learn more quickly and deeply from a combination of words and pictures compared to words alone, this is called the “multimedia principle” (Mayer, 2008) .
I wanted to add the narration audio separately. Getting the screen capture plus the narration correct at the same time, is just one extra challenge. Creating the narration audio separate adds more flexibility. The Udell (2006) interview talks about using a Microsoft product to record screencasts. This is no longer available, but I did find a free alternative from Microsoft; Expression Encoder 4 Screen Capture. I opened the resulting recording in Expression Encoder 4. Before encoding in .wmv, it appears you can edit the recording and adjust just about anything. In Encoder I added a separately recorded narration audio track made with a microphone and Audacity. I could not find a PC version of the Solarwalk app so I needed to find software to allow AirPlay from an iPod to the computer. I found Reflector2, which is free to try, but does insert a large watermark in the image. The resulting narrated screencast file is 55.6 MB.
Mayer, R., 2008. Applying the Science of Learning: Evidence-Based Principles for the Design of Multimedia Instruction” American Psychologist pp. 760-769.
Thomas, N., 2014. Dual Coding and Common Coding Theories of Memory. Retrieved from: https://plato.stanford.edu/entries/mental-imagery/theories-memory.html
Udell, J., 2006. What Is Screencasting? An Interview With Jon Udell. Retrieved from: http://www.masternewmedia.org//#ixzz4awvn4SNE