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Unit 11 – Science and Humanity. October. Title: Task 5: Changes that occur during the carbon cycle and the effects on climate change. . Prior learning There are 3 kinds of rock – sedimentary, metamorphic and Igneous
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Unit 11 – Science and Humanity October Title: Task 5: Changes that occur during the carbon cycle and the effects on climate change. • Prior learning • There are 3 kinds of rock – sedimentary, metamorphic and Igneous • Igneous rocks form crystals depending on the length of time it takes them to cool down • Theory of continental drift • Rock cycle • Key words • Photosynthesis, respiration, decomposition, decomposers, decay, carbon, cycle, fossil fuels, combustion, greenhouse effect, climate change,
IAM LEARNING: Describe the long-term changes that have occurred in our universe to our solar system and earth I WILL BE SUCCESSFUL IS I CAN: Identify the changes of the carbon cycle Understand what the combustion of fossil fuels are Explain the greenhouse effect Explain the theory behind climate change I CAN: Complete the stages in the carbon cycle Explain how the combustion of fossil fuels impacts on the carbon cycle and how this in turn impacts on the greenhouse effect Explain the link between climate change and fuel consumption and identify any governmental measures that are or are planned to be put in place to reduce the effects Unit 11 – Science and Humanity
STARTER: What am I? Mantle • I’m a viscous semi-solid withconvection currents circulating in me. • I’m iron and nickel too, but I’m liquid. • I just hang around on the outside. • I’m really very thin and am mostlysilicon, oxygen and aluminium. • I am dense, very hot, made mostly ofsolid iron and nickel. Outer core Atmosphere Crust Inner core Unit 11 – Science and Humanity
Mars Venus The early atmosphere • The Earth was formed about 4,500 million years ago. • During the first billion years there was intense volcanic activity, which produced the early atmosphere. This would have contained large quantities of carbon dioxide (CO2) and water vapour. Methane (CH4) and ammonia (NH3) are thought to have also been present. • This is rather like the atmosphere on Mars and Venus today. • The water vapour condensed to form the oceans. Unit 11 – Science and Humanity
Earth Photosynthesis increased oxygen levels Oxygen levels increase • Carbon dioxide reacted with rocks and much became trapped in them. • The evolution of algae some 3,000 million years ago, and subsequently plants which successfully colonized the Earth’s surface, led us towards the present atmosphere. • Their photosynthesis replaced carbon dioxide with oxygen. • Over a period of time, billions of tonnes of carbon dioxide became locked up in fossil fuels. Unit 11 – Science and Humanity
1% 21% Nitrogen Oxygen Other 78% Nitrogen appears • As oxygen levels rose, atmospheric ammonia (NH3) reacted with oxygen(O2) to form water (H2O) and nitrogen (N2). • Also, living organisms, including denitrifying bacteria, broke down nitrogen compounds releasing more nitrogen into the atmosphere. • And so the atmosphere headed towards a composition that has remained fairly constant for the last 200 million years. Unit 11 – Science and Humanity
Atmosphere timeline Copy the timeline and arrange the blue boxes in appropriate places along the line. Now 4,500 million 3,000 million 2,000 million 1,000 million 500 million 200 million H2O N2 O2 No gases CO2 NH3 CH4 H2 and He Volcanoes Algae Plants Unit 11 – Science and Humanity
Atmosphere Timeline No gases All positions are approximate Plants Algae Volcanoes Now 4,500 million 3,000 million 2,000 million 1,000 million 500 million 200 million O2 N2 H2O CO2 NH3 CH4 H2 and He Unit 11 – Science and Humanity
100% carbon dioxide nitrogen 50% Composition percentage oxygen now 0% 0 5,000 3,000 Time (millions of years) PLENARY: Changing gas levels Use the graph to estimate the answers. • How long ago was the atmosphere 75% CO2? • How long ago were the CO2 and N2 levels in the atmosphere equal? • How long ago was the atmosphere 50% nitrogen? Approx 4,000M Approx 3,300M Approx 2,000M Unit 11 – Science and Humanity
IAM LEARNING: Describe the long-term changes that have occurred in our universe to our solar system and earth I WILL BE SUCCESSFUL IS I CAN: Identify the changes of the carbon cycle Understand what the combustion of fossil fuels are Explain the greenhouse effect Explain the theory behind climate change I CAN: Complete the stages in the carbon cycle Explain how the combustion of fossil fuels impacts on the carbon cycle and how this in turn impacts on the greenhouse effect Explain the link between climate change and fuel consumption and identify any governmental measures that are or are planned to be put in place to reduce the effects Unit 11 – Science and Humanity
Earth Ozone: a vital filter 3O2 2O3 oxygen ozone • Oxygen normally exists as pairs of atoms (O2). • Oxygen can, however, turn into another form that has three atoms joined together. This is ozone (O3). • As oxygen levels rose, so did the amount of ozone. • This layer of ozone in the atmosphere filters out harmful ultraviolet rays from the sun. This will have allowed new organisms to evolve and survive. Harmful UV rays stopped with ozone layer Harmful UV rays reach Earth’s surface without ozone layer Unit 11 – Science and Humanity
The carbon cycle Unit 11 – Science and Humanity
CO2 release or consumption? Unit 11 – Science and Humanity
Carbon dioxide and temperature Over millions of years the carbon cycle has maintained a constant, low percentage (approx. 0.03%) of carbon dioxide in the atmosphere. In 1860, the CO2 level was about 289 ppm (parts per million). Here is a table showing the CO2 levels over a recent 10-year period. • What percentage change is this and does it matter? Unit 11 – Science and Humanity
200ppm CO2 300ppm CO2 Changing CO2 concentrations We also know the temperatures over the same period. The very warm interglacial period of 130,000 years ago was accompanied by CO2 levels of around 300 ppm. The previous great Ice Age had CO2 levels around 200 ppm. From air trapped in Antarctic ice, we have a good idea of CO2 concentrations going back 160,000 years. Which label goes with each picture? Unit 11 – Science and Humanity
Earth More CO2 balanced same temp Earth The greenhouse effect Heat loss Heat from sun Normally the Earth absorbs heat and emits heat at the same rate. Because of this the temperature remains constant. Certain gases, like CO2 and methane, act like a greenhouse. They let heat in but do not let it out. This is called the greenhouse effect. This means that the more CO2 there is, the hotter planet Earth is! Heat loss Heat from sun hotter And hotter! And hotter Unit 11 – Science and Humanity
Work through Task 5: Effect on Climate Change using the information you have gathered in the past lessons Unit 11 – Science and Humanity