THE EARTH IN SPACE The Earth in Space HOW WE DETERMINE TIME USING THE SUN AND EARTH The Earth in Space

Objectives What is rotation and how does it affect Earth What is revolution and how does it affect Earth Be able to compare and contrast rotation and revolution How day and night are determined How a year is determined

Determining Day and Night Axis – an imaginary line that goes through a planet, moon or other space object. The space objects “spins” on that line like a wheel on an axle.

Rotate - To turn around an axis Determining night and day

Courtesy of The Freeman Institute

Period of rotation/rotation Determining night and day Period of rotation/rotation The time it takes an object to turn on its axis Earth’s period of rotation is about 24 hours This determines 1 DAY ON EARTH

Revolution http://esminfo.prenhall.com/science/geoanimations/animations/01_EarthSun_E2.html

Revolution – one object moving around another Period of Revolution - the time it takes one object to move around another It takes the Earth 365 ¼ rotations to make 1 revolution around the sun so we have 365 ¼ days pr year These are counted for 3 years and on the 4th year we add the quarters up for 366 days and add that day in February – LEAP YEAR Orbit – the path an object takes to move around another object Determining a planetary year

In your science notes create a double bubble thinking map to compare Period of rotation Period of revolution In your science notes create a double bubble thinking map to compare And contrast Rotation and Revolution - remember you may have more bubbles than what is represented in the diagram above