Activity overview
Science topics:
Rocks
Take a much closer look at this familiar object. Can your class use their reasoning skills to work out what it is?
Run the activity
You will be zooming in and out of the image above – starting very close and stepping back slowly.
1. Start by asking everyone:
- What do they think the image is and why?
- What does the image remind them of and why?
2. Every time you zoom out, ask the class:
- Can they describe the colours, shapes and textures?
- What do they think the image is now – have they changed their minds?
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How to run Zoom In, Zoom Out activitiesBackground science
Chalk is a soft, whiteish rock and is a type of limestone. It is normally formed underwater, commonly on the sea bed, mostly from the skeletons of tiny sea creatures, called coccoliths. It takes many years to form. When you examine chalk closely, it has very fine grains and it can be scratched with a coin. Chalk is very porous which means that it can soak up and store water. There are many chalk hills (downlands) in southern England, and the White Cliffs of Dover and the Seven Sisters are well known examples of chalk cliffs found by the English Channel. The cliffs are eroded by waves and every few years more of the cliff above collapses.
Take it further
Activities
What other rocks can you name? Children could identify a set of rocks by looking closely at their appearance. With sedimentary rocks children should be able to see grains in layers, whereas igneous rocks have randomly arranged crystals. Metamorphic rocks are often crystalline, and some have visible bands. Children could use this key to identify their rocks. Science Sparks has a series of tests children can do to identify different properties.
Children can test a rock’s porosity by dripping water onto it and seeing how much is absorbed. They could also put a sample of rock into a cup of water and count the bubbles that appear. Rocks with the most bubbles have spaces between the grains that air and water can flow through.
Watch
This BBC clip showing how different rocks are formed.
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Find out more about pebble beaches with this Big Question: Why don't all rocks look the same? or find out more about fossils by asking the class What if fossils didn't exist?