Earth's Orbit and Rotation

An orbit is the path an object follows as it moves around another one. Earth moves in a circle around the sun once every 365.25 days. We call that path Earth’s orbit.

A tool that provides evidence that the earth is rotating. It is made of a heavy weight hanging from a long wire which swings back and forth. The direction of the swinging ball appears to change due to Earth’s rotation.

Solar System

A model of the solar system which puts the Sun at the center and says that the plants orbit around the sun. “Helio” means relating to the sun and “centric” means in the center. Today we know that this model is correct.

An ancient tool used to tell time during the day. Part of it casts a shadow onto a flat surface marked in hours. It works due to Earth’s rotation.

The apparent shift of position of some stars through the year. This was not able to be explained by the Geocentric model which said that everything orbited the earth. The Heliocentric model was able to explain stellar parallax.

Stellar Parallax

Constellations

Foucault Pendulum

The action of the earth turning or spinning around its center. If you stand in one place and turn all the way around, you have rotated. The earth rotates (spins) once every 24 hours.

An ancient model of the solar system which we know today is not correct. It puts earth at the center of the solar system and says that everything orbits around the earth. “Geo” means earth and “centric” means in the center. Today we know that the earth orbits around the sun.

Earth's Orbit

A dark shape made when an object blocks light. When you stand outside, your body blocks sunlight and that makes a shadow.

A year with one additional day added. We have leap years every 4 years because one orbit of the earth around the sun is 365.25 days. Our normal calendar has 365 days so every 4 years we have a leap year which adds an extra day.

Our solar system is made up of the sun, 8 planets and their moons. The planets all orbit around the sun and moons orbit around a planet.

Leap Year

Earth's Rotation

Shadow

A group of stars that form a recognizable shape such as the big dipper. Today there are about 90 constellations.

An area on Earth that has a specific time that all people living there can set their clocks to. There are 24 different time zones.

Time Zone

Sundial

Heliocentric model

Geocentric model