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Learn about the importance of the earth's atmosphere, the cycling of matter, and the human impact on climate change. Explore the carbon and water cycles and understand how matter is used and returned to the atmosphere.
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At the end of this unit you should: • Be able to understand the importance of the earth’s atmosphere and what gases it is made up of. • Know what matter is and that matter is transferred from one living thing to another and between a living thing and their environment. • Be able to describe how matter is used and returned to the atmosphere. • Be able to describe the carbon and water cycles. • Know the four processes in the water cycle. • Understand the human impact on the cycling of matter. • Be able to put forward ideas on how to reduce the factors of climate change.
biomass carbon climate change condensation cycle cycling of matter decay deforestation evaporation fossil fuels greenhouse effect matter micro-organisms nitrogen precipitation recycled run-off transpiration water
Explain what matter is. Matter is anything that takes up space and has mass.
(b) Why do all living things depend on the cycling of matter? Because all living things need water, carbon and nitrogen to live.
LIGHTBULB QUESTION Water collects in streams and rivers and flows into lakes and out to the sea. The water evaporates into the atmosphere, where it is then held in the clouds as water droplets.
(a) list the four processes of the water cycle. Evaporation, transpiration, condensation, precipitation. (b) Does water disappear when used? Explain. No. It goes through a cycle of events that returns it back to the earth.
(c) Wally is a tiny water droplet who has just been evaporated. He wants to return to the leaf of the oak tree he was hanging out on with his friends. Apply the processes of the water cycle to tell Wally how he is going to get back to the tree. You can use a diagram to help you explain the story to him.
(c) (i) Tell him what forms he might take along the way. (ii) Tell him what will happen when he meets some animals, and how he will survive this. Wally will cool and form into water droplets, which, along with many other of his friends, will form into a cloud. This cloud will become heavier and Wally will fall to the ground as rain or maybe snow or sleet. Wally could fall to the ground and soak into the soil, or straight into a stream, river, lake, sea or ocean. When in the soil, Wally will be taken up by roots of a plant. He will travel up through the xylem vessel in the plant and make his way back to the leaf of the plant.
Investigation 16.01.01: Create a model that demonstrates the water cycle Equipment: Large transparent box/large lunch box, a clock glass or evaporating dish, strong paper towels (four sheets), lamp/direct sunlight at a window, permanent marker, food colouring (optional), water, two ziplock sandwich bags, ice.
Investigation 16.01.01: Create a model that demonstrates the water cycle Instructions: 1. Using an area in front of a window, or an area where your lamp can be plugged in, place a single layer of paper towel over your working area. 2. Draw a line around the inside of the top of the clock glass or the evaporating dish. (Note: The line allows the immediate observation of any water level changes to be made.) 3. Place the clock glass or evaporating dish on top of the paper towel to one end of the working area. 4. Place water up to the line, being careful not to spill any onto the towel. (Note: Food colouring can be added here if so wished.)
Investigation 16.01.01: Create a model that demonstrates the water cycle Instructions: 5. Turn your box upside down and place it so it covers the paper towels and the clock glass/evaporating dish. 6. If using a lamp, place it so it shines on the water. 7. You will need to leave the lamp on, checking the water level every thirty minutes if possible. Leave the lamp on overnight if possible. Record observations made. 8. The next day, record whether the water level has decreased.
1. What is the job of the sun/lamp in your water cycle? • It provides the heat energy.
2. Suggest what would be the effect of having different water volumes? • It would take longer for all the water to evaporate but the same result should still exist.
3. What happens to the water in your model? • The water level in the dish decreased. It evaporated and fell to the base of the box as the paper towels became damp.
4. What is the purpose of the paper towels? • To prove that the water did evaporate and then condensed and returned to the base of the box as the towels became damp.
5. How does the water become precipitation? • The water droplets evaporate, and when they touch the sides of the box they condense and slide to the bottom as ‘rain’.
6. Is there a way you could improve your model? Hint: Think about the processes of the water cycle and what causes them to happen. • Ice could be placed in the zip-bags and placed on top of box to reduce the temperature of the environment. Observations and comparisons could then be made. A thermometer could be used to record the temperature over the time, and observations made to see if the temperature was consistent.
Copy and complete Table 16.01.02 regarding the effect of human actions on the environment.
Investigation 16.01.02: Showing the importance of plants/trees to our water supplies Equipment: Three 2-litre empty plastic bottles and caps, three 1-litre bottles or smaller, soil, cress or radish seeds (alternatively, plants ready to be transplanted), water, knife, string.
Investigation 16.01.02: Showing the importance of plants/trees to our water supplies Instructions: 1. Label the bottles 1, 2 and 3. 2. Cut a groove out of each of the bottles as shown in Fig. 16.01.01. 3. Place soil in the three bottles, just below the neck. 4. Wet each bottle of soil with the same amount of water. 5. Sow cress/radish seeds in Bottle 1. These will take 3–5 days to grow. Screw cap back onto Bottle 1. 6. Place twigs and dead leaves in Bottle 2 and screw cap on. 7. Leave Bottle 3 with only soil and with cap on.
Investigation 16.01.02: Showing the importance of plants/trees to our water supplies Instructions: 8. Cut off the bottoms of the three smaller bottles. Having made two holes through these bottoms on either side, loop string through them. Then tie and hang these as shown in Fig. 16.01.02. 9. When seeds start to grow, water every day or when needed. When watering Bottle 1, also water Bottle 2 and Bottle 3. 10. After two days of good growth and watering, remove all the bottle caps. 11. Observe and compare the water that collects in the bottle ends over a five-day period. This may vary/take a day or two longer for a result if growth takes longer.
1. Why does the third bottle contain only soil? • This will be the control and proves that the soil needs plants growing in it to continue the water cycle. The result here can be compared to the other two.
2. Why is it important to add water to all bottles and not just the bottle with the seeds? • To make it a fair test.
3. What type of water do you think will come from the three bottles? Explain. • Bottle 1: clear water; Bottle 2: a light brown colour; Bottle 3: a dark brown dirty water. • Bottle 1: The clear water will be present as the plants ensure that water is in a continued cycle, whereby it is drawn up into the plant to be used. The soil will store more for the plants to take up. • Bottle 2: The water will have a light brown colour as some water will be used up but not enough to encourage the continued cycle of water, and therefore the water will be a little brown from the soil. • Bottle 3: There is no cycle of water happening and the water in the soil is building up, hence the water is nearly the same colour as the soil.
(a) Scientists have been monitoring carbon dioxide levels in the atmosphere. Discuss or write a few sentences on what you think scientists have concluded in their research. (Hint: See Units 9.2 and 9.3.) They have discovered that with the increased carbon dioxide levels, the atmosphere is warming up. There is an increased amount of fossil fuels being used and an increased amount of deforestation, so more carbon dioxide is being produced but it is not being recycled. Therefore it enters the atmosphere, increasing the temperature, leading to global warming.
(b) How does our use of water have an effect on the water cycle? We only have a small amount of water available for us to use. Therefore it is important to use it wisely. Reckless use of water could lead to an unrecoverable amount available for us to use.
(c) How are the carbon and water cycles similar? Both cycles rely on the atmosphere. Both rely on continued cycles to occur for matter to be available to use over time. Plants and animals rely on both to survive. (Other suggestions could be valid.)
The rate of change being experienced by the earth’s varying climates is greater than in the past. The carbon and water cycles have contributed to this climate change. Why do you think the earth’s climate has changed? Human/environmental impacts on the carbon and water cycle have contributed to climate change. The climate has been changing for thousands of years but today the rate of change is much quicker. It has changed because: the population of the world is increasing; standards of living are increasing; pollution is increasing; land availability is decreasing; more fossil fuels are being burned (factories and vehicle engines).
(a) Climate change causes more floods, droughts and storms. What direct effect do these events have on habitats? These events destroy habitats, with plants dying out because of a surplus/lack of water, or by being destroyed in storms. The loss of plants brings about the loss of a food source and shelter for animals, as well as the loss of the recycling of water, carbon and nitrogen.
(b) Why are food prices for certain food items increasing? Food prices are increasing because it is becoming more difficult to successfully cultivate and harvest certain food items. Horticulturists and farmers are losing more of their produce due to floods and droughts. Thus prices go up as stock diminishes.
(c) Why are scientists urging us to reduce the amount of greenhouse gases in the atmosphere? Atmospheric temperature is increasing because of greenhouse gases. Droughts, storms and flooding will only continue to get worse if we do not try to reduce greenhouse gases. This will then lead to the price of foods rising as the cost of growing or producing them will also rise.
Copy and Complete In this unit I learned that matter is water, nitrogenand carbon. Matter works in a cycle where it is transferred from one living organism to another and also into the atmosphere. In the water cycle there are four processes that happen: evaporation, transpiration, condensation and precipitation. No water is lost: it just changes from a liquid to a gas and back again. Carbon is transferred through the food chain: from the plant to the animaland from one animal to another. When a plant or animal dies, the carbon that is inside them is released back into the soil or atmosphere. Climate change is the changes to the weather patterns, such as the average temperature, rainfall and the amount of airand water pollution. Due to climate change, farmers in Ireland do not know when to sow seeds, or harvest their crops. We can protect against climate change by reducing, reusing and recycling.
1. Make a list of reasons why forest areas are being cut down at such a high rate. Because of an increase in population, there is an increase in demand for housing – both in terms of area to build in and material to build from – as well as attendant products made from timber. For access to new areas of population, forests are cut down and roads built.
2. How does deforestation directly affect the levels of greenhouse gases? Carbon dioxide is no longer taken in by the tree and locked away until the tree dies and decays. This then leaves the levels of carbon dioxide in the atmosphere higher.
3. ‘Burning fossil fuels is the biggest contributor to the increased levels of carbon dioxide.’ Explain this statement. Fossil fuel examples are coal, oil and natural gas. When burned they release carbon dioxide into the atmosphere and release a lot of it at once.
4. How is rain formed? Water droplets that have built up in clouds become bigger and fall to the ground as rain.
5. Where does rainwater go? Water can move across the surface of the ground and run into ponds, rivers and seas, or it can seep through spaces in rocks or soil, soaking into the ground. It can then get used up by plants or animals or evaporate back into the atmosphere, whereby the cycle starts again.
6. Why do all living things depend on water? (Hint: See Units 6.2 and 8.3.) Water is essential for life: plants need water for photosynthesis (to make food); animals need water to hydrate the body, for chemical reactions to happen and for the blood to be able to transport substances around the body.
7. Name and describe what is happening at each stage numbered in Fig. 16.01.10.
7. Name and describe what is happening at each stage numbered in Fig. 16.01.10.
8. Explain how the human activity depicted in Fig. 16.01.11 could contribute positively as well as negatively to the life of a community. Positively: Jobs are provided for the community; trees can be used to make produce; allow houses and roads to be built. Negatively: Removal of trees increases the amount of carbon dioxide in the atmosphere and contributes to global warming.
