TERM 4: Planet Earth AnD BEYOND Planet Earth and beyond The planet Earth moves Fossils Surface of the Earth Sedimentary rocks Unit 1 The planet Earth moves Orbits the sun The planet Earth moves Spins around its own axis Doc Scientia - Natural Sciences and Technology - Grade 5 101
Planet Earth and beyond Earth is a planet. A planet is a body in space that revolves around a star. A planet does not emit its own light, but reflects the light of the sun. There are eight planets in our solar system. The names of the planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Earth has an atmosphere which makes life possible. There are other planets that also have an atmosphere, but they are not suitable for life. Mercury Mars Neptune Earth Venus Jupiter Uranus 102 Doc Scientia - Natural Sciences and Technology - Grade 5 Saturn
The planets move around the sun. This action is called orbiting or revolving. The paths on which they move around the sun, are called orbits. Order of planets from the sun 1 3 5 7 Mercury Earth Jupiter Uranus Venus Mars Saturn Neptune 2 4 6 8 Watch this! Jupiter is the largest planet. 1 300 Earths can fit into Jupiter. Doc Scientia - Natural Sciences and Technology - Grade 5 103
When looking at Earth from space, it is a bright shiny ball. About 70% of Earth s surface is covered with water. Therefore, Earth is referred to as the blue planet. What is the matter? You look a little blue. Earth looks smaller than Venus. The reason: Venus has a thick layer of gas around it that makes it look larger than Earth. Oh, you know... most people know me as the blue planet. 1.1 Earth orbits the sun The planets revolve around the sun. The paths on which they move around the sun, are called orbits. These orbits are elliptic a bit like a squashed circle. These orbits always remain the same. Earth moves around the sun very fast, approximately 30 kilometres each second. If we could move that fast, it would take 3 seconds to complete the Comrades Marathon of about 90 km. The moving of the planets around the sun is called orbiting or revolving. Despite how fast Earth moves, it still takes 365¼ days to go around the sun once. The time for one orbit around the sun is called a year. 104 Doc Scientia - Natural Sciences and Technology - Grade 5
Every fourth year, the quarters are added together. This is called a leap year and consists of 366 days. The length of a year is different for different planets. The further away the planet is from the sun, the larger its orbit is, and the longer it takes to orbit the sun. Jupiter s year is 4 332 Earth days. The following table shows how the length of the year differs for the different planets: Well, clea rly it is speed that ma 30 km per second? kes our old Ea rth happy. Bbbbrrmmmm!!! Bbbbrmmmmm!!! Planet Time of one orbit around the sun (measured in Earth days) Mercury 88 Earth days Venus 225 Earth days Mars 687 Earth days Jupiter 4 332 Earth days Doc Scientia - Natural Sciences and Technology - Grade 5 105
Planet Time of one orbit around the sun (measured in Earth days): Saturn 10 756 Earth days Uranus 30 687 Earth days Neptune 60 190 Earth days Note: You do not have to remember the lengths of the years of the different planets. AGAIN? When is it my turn? On your 11 th birthday, you are 11 x 365 days old = 4 015 days plus about 3 extra leap year days = 4 018 days. On Jupiter you would not even be one year old yet. Sorry Jupiter, but your turn is not TOO far off! 106 Doc Scientia - Natural Sciences and Technology - Grade 5
1.2 Earth turns around its own axis Earth turns around its own axis, which is just an imaginary line through its centre. This is illustrated in the sketch. North Pole South Pole When an object spins around an axis, we say it is rotating. Earth takes approximately 24 hours to spin around its own axis once. This is called a day. The side of Earth turned to the sun has daytime. The side of Earth turned away from the sun has nighttime. Practical task 6 Date:... Aim: To demonstrate the rotation of Earth around its own axis. Requirements: A soccer ball or similar ball A flashlight Adhesive tape A 10 cm 10 cm coloured piece of paper Doc Scientia - Natural Sciences and Technology - Grade 5 107