EARTH STRUCTURE
Fourth Term Science – Sixth Grade
Dynamic
Earth
It may seem like the Earth is made up
of one big solid rock, but it's really
made up of a number of parts. Some
of them constantly moving!
You can think of the Earth as being
made up of a number of layers, sort of
like an onion. These layers get more
and more dense the closer to the
center of the earth you get.
Earth's
layers
Draw this on your notebook!
■
Do you think this layer
solid
The crust is theis
thinnest
and or
outerliquid?
layer of the Earth where we live, including
animals, mountains, sea and soil.
■ The crust varies from around 5km thick (in the ocean floor) to around 70km thick
(on land where we live called the continental crust)
Write down the underlined sentences
Do you think this layer
is
solid
or
liquid?
It is made molten, or melted, iron, minerals and other semi-solid rocks that will still flow
■ The mantle is about 2,900km thick and amazingly it makes up about 85% of the Earth’s
weight. Wow! That’s one heavy layer.
■
under pressure.
■ In this layer the rocks rise. Those clever scientists think that when they rise from the very
intense heat, and then cool down again, that they sink back to the core. This movement
makes the crust break into plates, or different sections.
Write down the underlined sentences
Which core was solid and
which one liquid?
■ The Earth was formed 4.5 billion years ago, and when this happened, all the heavy materials
sunk to the middle and this became the inner core. The lighter ones like air and water stayed on
the top on the crust.
■ The Earth's outer core is made up of iron and nickel and is very hot (4400 to 5000+ degrees C).
This is so hot that the iron and nickel metals are liquid!
■ The Earth's inner core is made up of iron and nickel, just like the outer core, however, the inner
core is different. The inner core is so deep within the earth that it's under immense pressure.
So much pressure that, even though it is so hot, it is solid. The temperature in the inner core is
between 4, 982⁰ and 7,204⁰C
Write down the underlined sentences
Which layer do you think is the biggest?
Which layer is the
hottest?
Remember that some layers are liquid and
others solid, do you think they are moving?
They move
because of
convection
Convection is heat transfer due to a density differential
within a fluid.
When the fluid molecules are heated, the fluid
becomes larger and lighter. The heated molecules take
up more space and rise to the top, while the cooler
molecules sink to the bottom.
Write down the underlined sentences
HOMEWORK
■ Find out what are tectonic plates and write it down
■ Go to the blog https://scienceblog5th.wordpress.com/ and download the Tectonic
Plates file. Print it, paste it on your notebook and do the activity
■ Bring two small boxes, a strip of paper and tape