Doc Scientia - Natural Sciences and Technology - Grade 5 101
Unit 1
TERM 4:
Planet Earth AnD BEYOND
The planetEarth moves
Surface of the Earth
Orbits the sun
Spins around its own axis
Sedimentary rocks
The planet Earth moves Fossils
Planet Earth and beyond
The planet Earth moves
Doc Scientia - Natural Sciences and Technology - Grade 5102
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 NeptuneMars
Earth JupiterVenus
Uranus Saturn
Doc Scientia - Natural Sciences and Technology - Grade 5 103
Planet Earth and beyond
The planets movearound the sun. This action is called orbiting or revolving.
The paths on whichthey move around the sun, are called orbits.
Order of planets from the sun
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
1
2
3
4
5
6
7
8
Watchthis!
Jupiter is the
largest planet.
1 300 Earths
can fit into Jupiter.
Doc Scientia - Natural Sciences and Technology - Grade 5104
Planet Earth and beyond
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.
Earth looks smaller
than Venus. The reason:
Venus has a thick layer
of gas around it that
makes it look larger
than Earth.
What is the matter?
You look a
little blue.
Oh , y o u k n ow . . . mo s t p
e o pl e
k n ow
m e a s t h e b l u e p la ne t .
1.1 Earth orbits the sun
The planets revolve around the sun.The paths on which they movearound 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.
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.
The moving of theplanets around the sun is called orbiting or revolving.
Doc Scientia - Natural Sciences and Technology - Grade 5 105
Planet Earth and beyond
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 itsorbit is, and the longer it takes to orbitthe sun. Jupiter’s year is 4 332 Earth days.
The following table shows how the length of the yeardiffers for the different planets:
Bbbb r r m mm m ! !
!
Bbbb r m m mm m ! !
!
W e l l , c l ea r ly it is s p e ed t h at
ma k e s o ur o ld Ea rt h h ap p y .
30 km p e r s e c o nd?
PlanetTime of one orbit around thesun (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 5106
Planet Earth and beyond
PlanetTime of one orbit around thesun (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.
On your 11th 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.
AGAIN?
When is it
my turn?
Sorry Jupiter, but your turn is not TOO far off!
Doc Scientia - Natural Sciences and Technology - Grade 5 107
Planet Earth and beyond
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