The earth is astonishingly old and was formed 4600 mya by a massive explosion we call the big bang. We explored these huge concepts in understanding the origin of the earth, its immense age and how it changes over time with resources easily available at all schools: stones, water, clear plastic bottles, a large piece of plastic sheeting and a toilet roll.
It is really fun unrolling toilet paper, bashing stones together and playing with water and that is exactly what the learners in the Gr 5 classes from Sophakama and St Mary’s RC primary schools did.
Understanding how old the earth is
If you unroll a toilet roll there are about 500 squares. If we pretend that each square represents one million years (1000 000) then a single roll of toilet paper can take us back in time 500 mya (=500 million years ago).
If we connect this to what we know of the earth’s history by looking at the fossil record in the layers of rock scientists tell us that the earth is 4 600 million years old which is about 9 toilet rolls of time.
Everybody made an exploding noise as rocks clashed simulating the massive collisions in space that earth experienced at the beginning.
The rock cycle and the water cycle sculpt the surface of the earth.
Rocks on earth today are made of the same matter from that original collision but they have been recycled and remade many times. To simulate this process we rubbed rocks together to make soil and then mixed it with water in a bottle.
The sediment soon settles out at the bottom and everyone was able to see this.
We simulated the process of erosion with 3 learners being the mountains underneath a large sheet of plastic. Water poured on the highest parts run downhill forming rivers in the valleys. Sediments are washed down into the blue basin sea and settle out into layers.
Fossils are the remains of animals and plants from long ago
Over millions of years these layers of sediments slowly turn into rock through pressure and heat.
Animals and plants that lived on earth millions of years ago became trapped in these sedimentary layers and have turned into stones. We call these fossils.
I am not sure if it was more exciting to hold a real fossil that is millions of years old or to make your own fossil with clay, plants and shells.
We worked with the evolution cards to understand how animals and plants have changed over time. The announcement of the fossil finds at the Cradle of Human Kind was of course relevant to our lesson. We discussed where the newly discovered Naledi man fits in to the development of modern human beings.