Quick: Explain to a 12 year old (or just about any 52 year old, for that matter) why the moon has phases. Ok, why does the earth have seasons? Still too hard? Why do ocean tides behave the way they do? What is the significance of the Tropic of Cancer and Tropic of Capricorn (and I don’t mean those Henry Miller novels)? OK, name the zodiacal constellations. All too hard for you? You sort of know, but not real sure about all the details? Then get Solar Walk for the iPad now. It’s only $2.99, and this is just a little of what it will teach you (and more to the point, enable you to explain to your kids in a way that they will get it right away). There’s nothing like actually seeing a thing to explain it.
In addition to brief and to the point earth-related movies—which look spectacular, by the way—this app will:

Reduced screen shot of earth's core from Solar Walk
This is definitely a 5-star app worth having at 4-times the price.
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