a. Mindful moment.
This morning at about 6:15 Indian Standard Time. E 9/15 Vasant Vihar, New Delhi. Looking a few degrees south of due west. (Note: The photo of the sun on the current blog header was taken a few days before the autumnal equinox just before sunset looking in the same general direction.)
c. Preview today’s blogpost.
d. Create today’s DSN entry/document.
e. Questions. Are you prepared for Parent Student Teacher conferences?
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- Make a new folder inside your DSN. Name it Astronomy. Put today’s DSN in this folder. We are opening the astronomy unit to give you time to begin watching the sky. You will have an opportunity during WOW 8 by being outside during the day and the night to make observations. You should know what to look for and how to look.
- Inside the Astronomy folder, make another document. Call it Moon Journal. You will need to make repeated observations of the moon–your location, the time you see the moon, the date, the moon’s location in the sky (bearing and elevation), and the moon’s phase. You will need to make a sufficient number of observations during two cycles so that you can begin to explain what the moon does and why it appears to us as it does.
- We will discuss today–naming/observing directions along the horizon (bearing / azimuth) and describing/measuring angular elevation/altitude above the horizon. We’ll use your compass app. (Try to find out how it works.) And we’ll use your app to measure angles. (How do you think it works?) The concepts of horizon, celestial meridian, local noon, zenith, celestial sphere, celestial equator, ecliptic are important.
- We will look at two sundials: horizontal and universal. We will discuss how they work.
- We will talk about the apparent motion of the sun and the moon.
- We will discuss the challenge of reconciling what we see from our position on the earth with “explanatory” views that try to offer a view of the earth-moon-sun system and the solar system that we never experience. Changing points of view is a difficulty that many students face.
- We will discuss the importance of using properties of triangles and circles to indirectly measures sizes and distances in the solar system.
- We will take measurements of the tall kapok tree in the terrace between the m.s. rocks and the Tiger’s Den and use a carefully made scale drawing to determine its height. See diagram on board. This method uses properties of similar triangles.
- See the accomplishments of Eratosthenes on calculating the size of the earth in Egypt around 200 B.C.E.
- Start at 9:27 for a modern recreation of Eratosthenes’ method to figure out the size of the earth. (This is a great video on mapping from The Ring of Truth. I hope you have watched the episode linked on a previous blogpost on Atoms.) https://www.youtube.com/watch?v=yRY2SkMTafc
- See the accomplishments of Aristarchus in attempting to figure out the sizes and distances of the sun and moon in the 3rd century B.C.E. http://astrosun2.astro.cornell.edu/academics/courses/astro201/aristarchus.htm
Watch this video–it is pretty good. Keep it with your references, like: