Science - Unit 7 - Weathering And Erosion

What is weathering?

The wearing away of rocks and erosion to be the movement of broken pieces away from the site of weathering by water, ice or wind. The two types of mechanical weathering are freeze-thawing and exfoliation. Freeze-thawing involves the rain entering the cracks in the rocks, the rain then freezes which pushes the rock further apart. Eventually, the rock completely breaks apart. Exfoliation involves the heating of a rock on a hot day, which causes the outer layer to expand. When the rock cools down, it contacts again, causing small pieces of rock to flake off. Biological weathering involves tree roots growing thick and strong underground which make their way into the cracks in a rock and can force it to break. Chemical weathering involves the reaction of acidic rainwater with limestone, chalk or marble.

What are the impacts of global warming and the greenhouse effect?

Carbon dioxide, Water vapour and methane are examples of greenhouse gases. Greenhouse gases are helpful in maintaining a temperature of Earth warm enough to support life. But there are draw backs such as, extreme weather conditions, ice caps melting and loss of habitats. The greenhouse gas effect is a natural process, the sun radiates short wave UV radiation, the surface of the Earth absorbs some radiation and rest is deflected back out into space as long wave radiation. The presence of greenhouse gases means that some of the deflected radiation gets trap inside the Earth’s atmosphere leading to a raise in global temperature (global warming).

Human activity is causing the increase in climate change. These include farming cattle for food- production of methane, deforestation, burning fossil fuels. The effects of climate change are; coral reefs being eradicated; species extinction and rising sea levels results in less areas to inhabit.

Is the earth running out of resources?

Earth’s resources are important for survival, there is competition for warmth, shelter, food and transport. Some resources, for example fossil fuels, are finite resources which are not been formed fast enough to be considered renewable. Renewable resources are resources that are being formed faster than or at the same rate as they are being used. It is important that Earth’s resources are being preserved for future generations.

What is recycling and why is it important?

Recycling is the process of converting waste into reusable material, earths resources are limited and need to be used in a sustainable way.