| A | B |
|---|
| orbit | the path a body follows as it travels around the sun |
| ellipse | closed curve whose shape is determined by two points |
| perihelion | point where earth is closest to the sun |
| aphelion | point at which Earth is furthest from the sun |
| perihelion | 147 million miles |
| aphelion | 152 million miles |
| Earths orbital speed | 29.8 km/s |
| revolution | the motion of one body around another in space |
| Year | the time it takes the earth to travel around the sun |
| 365 1/4 | Number of days in a year |
| rotation | the spinning of Earth on its axis |
| day and night | the most observable effect of Earth's rotation |
| East to West | the direction that the Earth spins |
| Day | one complete rotation of the Earth on it's axis |
| Month | the time between two full moons (about 29.5 days) |
| calendar | system for measuring long periods of time |
| leap year | year where extra 1/4 days are lumped together |
| 24 | number of time zones |
| time zones | way to keep time uniform throughout the day |
| noon | time when sun is highest in the sky |
