Natural Sciences Grade 7 Term 4 Planet Earth
![FORMATION OF OIL AND GAS • Plankton [very small sea plants and animals] lived](https://slidetodoc.com/presentation_image/b11e8ea568f4465d3ae17c007a8d1202/image-7.jpg "FORMATION OF OIL AND GAS • Plankton [very small sea plants and animals] lived")
- Slides: 8
Natural Sciences Grade 7 Term 4: Planet Earth & Beyond Relationship of the Sun to the Earth
Topic 1 Relationship of the Sun to the Earth Stored solar energy Natural Sciences - Grade 7
Dead plants and animals form coal, oil or gas • In term 3 you learnt about renewable and non-renewable energy. • Fossils, [the remains of animals and plants that lived long ago, about 300 million years] are examples of nonrenewable energy. • Fossil fuels [e. g. coal, crude oil and natural]. • The Earth was warmer then and there were huge swamps. • Oil was formed from the remains of sea animals. Natural Sciences - Grade 7
Dead plants and animals form coal, oil or gas • Coal is formed from the remains of swamp or lake plants. • Plants and animals land in the water/ land/ swamps/ along the coast where they decay. Natural Sciences - Grade 7
THE FORMATION OF COAL • Long ago plants absorbed the Sun’s energy and the animals ate the plants. • When the plants and animals died, it landed in the seas, lakes, swamps and on land. • They were covered by sediment layers which protected their remains. • Their dead matter formed peat [a substance]. • The pressure increased above the peat, because more layers of mud, rock and soil formed on top of the remains. Natural Sciences - Grade 7
THE FORMATION OF COAL • This pressure resulted in the remains being pushed further down where it was warmer. • The remains changed into fossils fuels due to the pressure on peat as well as the Earth’s heat. • All plant substances mostly became coal. • The combination of animal matter and dead plants formed oil and natural gas. Natural Sciences - Grade 7
FORMATION OF OIL AND GAS • Plankton [very small sea plants and animals] lived millions of years ago. • Their remains dropped to the bottom of the sea when they died. • No normal decaying, because their remains were covered with sediments. • The three ways in which oil and gas are formed: - Sediment layers turn into porous stone [sandstone/limestone] through which the oil and gas seep. - cavities form between the rock layers and the oil and gas seep through these cavities. - the rocks that form above the cavities trap the oil and gas because they a are non-porous. Natural Sciences - Grade 7
FORMATION OF OIL AND GAS The picture of an oil rig harvesting gas and oil from the sea floor. Natural Sciences - Grade 7
