Science Year 3
Compare and group together different kinds of rock on the basis of their simple physical properties
Record findings using simple scientific language and labelled diagrams
Scotch egg or hard-boiled egg, sharp knife. Information books showing cross-section of the Earth.
Access to internet.
(could develop this further using Sessions 2 & 3, Mountain Ranges Theme, Mighty
Mountains Topic & links to Sessions 7 to 8a, Our Planet Theme, Adventure in Space Topic)
Sit chn in group and ask them to close their eyes and imagine they are sitting on the grass in school field/park/garden.
Write the word grass at the top of the flip chart. Ask What is underneath the grass? Write ‘topsoil’ (rich and dark with
rotting vegetation) below ‘grass’. Ask What is below the topsoil? Write ‘clay’ or ‘subsoil’ (tightly packed, different
colour). Continue down with ‘rocky soil’ (rocks breaking down into soil) then ‘bedrock’ (just rock). Could continue with
‘crust, mantle, outer core and inner core’ if chn mention any of this vocabulary. Sometimes the rocks do show on the surface of the Earth, or buildings, roads, etc. cover the rocks instead of grass (session resources). Can chn describe anywhere they have seen rocks on the surface of the Earth – perhaps cliffs or rock pools at the seaside or a local rocky outcrop? Rocks that are broken into smaller & smaller pieces eventually form sand. Soil is also made of tiny pieces of different rocks plus remains of plants & animals, air & water.
The crust is the thin outer layer of cold hard rock that covers the world (10km-90km thick). The mantle (extremely hot
rock that often flows like treacle) is 3,000 km thick. The core, which is made of metal, is hotter than the mantle. So the material that planet Earth is made of is rock, wherever you stand on earth there is rock beneath you and no other known planet in our solar system is like this. Explain that when the crust is very thin sometimes the liquid rock
(magma) escapes and this is a volcano (more about this in the next session!). Show a picture (session resources). Show chn a scotch egg (or a hard-boiled egg – shell is the crust) and ask them to imagine that it is planet Earth. Carefully cut it in half and show chn the cross-section. (Could introduce this idea with the book What’s Under the Bed by Mick
Manning and Brita Granstrom, ISBN 9780749627546 – if available, which can also inspire some good art work.)
Explain that there have been several attempts to drill deep into (or even through) the Earth’s crust. The deepest at
12,262m was drilled between 1970 & 1989 on the Russian Kola Peninsula. They hoped to go deeper, but the temperature became so high that they decided to stop before the drill stopped working!
Tell chn that the earth’s crust is broken up into sections called plates and these move in relation to each other.
Mountains are formed where plates bump into each other. This means that the countries of the world are moving very, very slowly over the molten rock in the mantle. Earthquakes & volcanoes occur at these places too. Look at diagrams in books or on websites, e.g. http://scienceresources.co.uk/KS3/Chemistry/Earth_Structure/Plate_Boundaries.htm
or http://www.enchantedlearning.com/subjects/astronomy/planets/earth/Continents.shtml
.
Independent activity:
Draw a carefully labelled picture of a cross section of the earth (see information books or session resources).
Point out that the labels should be written using printed, not joined up, handwriting. Write a paragraph describing the structure of the earth underneath.
Independent activity:
Having seen pictures of rocks on the surface of the earth in quarries, this site http://www.virtualquarry.co.uk/ is worth exploring for clips about quarries (sorting rocks, etc.), and also has games.
Practise vocabulary relating to session, e.g. crust, mantle, outer core and inner core, magma. Discuss how it is important to use the correct scientific vocabulary when writing or talking about science topics. Remind chn of the dangers of places like quarries and cliffs. Point out that chn will study soils in more detail in Sessions G & H.
1. Recognise that there is rock under all surfaces.
2. Describe the internal structure of the Earth in simple terms.
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