Term 2 review: Earth’s resources and patterns in the sky

Forces are pushes and pulls. Gravity is a pull between any two objects that have mass. Earth’s gravity pulls toward its centre, which is what “down” means, and it holds the Moon in orbit, while the Sun’s gravity holds the planets. Without air all objects would fall together, and air resistance slows paper and feathers. Earth rotates once in about a day, which makes day and night and makes the Sun and stars seem to rise in the east and set in the west. It revolves round the Sun in about a year. Earth’s axis keeps the same tilt, about 23½°, and points the same way, so as Earth goes round, different parts lean toward the Sun and we get seasons. Shadows are shortest around midday. The Moon shines by reflecting sunlight, and its phases come from how much of the lit half we see. The Sun is a star that looks brightest because it is the closest. Never look at the Sun.