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# Journey to the Moon, 1902... ...and The Equations of Motion

I've been continuing to work my way through Barry Luokkala's great book on teaching science through science fiction, which I'm finding both endlessly entertaining and a great source of material for class. This week, I was looking at the very first science fiction movie - and one of the earliest movies which still survives: Melie's 'La Voyage dans la Lune' from 1902 - and using his suggestions to use this to teach the equations of motion.

Meliere was a magician and based this film on books by both Jules Verne and HG Wells. In it the 'College of Astronomers' decide on a plan to sit into a large capsule which is fired out of an enormous cannon at a speed sufficient to reach the moon. Once there, they admire a very stylish earth-rise, encounter various types of aliens who attack them, and manage to return to earth by the interesting technique of pushing their capsule off a tall cliff - whereupon it falls the 400,000 km back to earth rather than the few hundred metres to the surface of the moon.

Obviously, Melies wasn't too concerned with scientific accuracy, but Luokkala does a great job nonetheless in analysing the story so that we can learn some basic physics from it. He reminds us that Newton had calculated the escape velocity of the earth at 11.2 km/s. When you remember that the capsule they used would have to reach that speed within the length of the cannon - which Jules Verne had put at 900 feet - you can calculate the g-forces involved and ask if the astronomers could have survived the jouney.*

He also uses the earth-rise scene to teach about how the moon is tidally locked, and so there are no earth-rises visible for the surface of the moon (though astronauts in orbit around the moon would see one decades later, and took a famous photograph when they did.)

And of course, the cliff-face escape is an interesting example of how people can totally misunderstand the concept of gravity, and presumably didn't seem ludicrous to an early 1900s audience - who may have lived 200 years after Newton, but also seventy years before the moon landings.

I've put together a PowerPoint of how I used this material in class, if anybody is interested. Available here - on the third line: Voyage to the Moon.

* spoiler: they couldn't