week of january 19, 2010

Something we learned about this week was equinox. There is an Autumn Equinox and a Spring Equinox. Equinoxes are when the Earth is not tilted away or towards the sun. In Equinox, the days and nights are about the same length.
We also learned about solstice. There is a Winter Solstice and a Summer Solstice. Solstices (solstici? (: ) are when the Earth is either titled towards or away from the sun. The days and nights are not the same length, in Winter the nights are longer and in Summer the days are longer.
This week we also learned that the Earth exerts a force on the moon (or the sun exerts a force on the Earth) like a magnet and a refridgerator. If a magnet is very close to a refridgerator, the fridge pulls the magnet so it sticks to the fridge. In the orbital simulation, if you put the Earth very close to the sun it would crash into it.
For an object to orbit:
- There needs to be at least two massive objects.
- If the velocity is too small, the object will crash.
- If the velocity is too large, the object will fly out of orbit.
- The closer the object, the more initial velocity it needs.
- The further away the object, the less initial velocity it needs.
- The initial velocity must go perpendicular to the sun's force for the object to orbit.

We learned all of this mostly by the orbital simulation and doing the 20 trials for homework.