1 / 33

Grade 8 Science

Unit 1: Water Systems on Earth Chapter 3. Grade 8 Science. A measure of how long it takes a material to heat up or cool down. Water has a high heat capacity... It takes a long time to heat up and a long time to cool down.

cfalk
Télécharger la présentation

Grade 8 Science

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Unit 1: Water Systems on Earth Chapter 3 Grade 8 Science

  2. A measure of how long it takes a material to heat up or cool down. Water has a high heat capacity... It takes a long time to heat up and a long time to cool down.  Oceans can store large amounts of heat. Currents will transfer this heat to other parts of the world. Heat Capacity ≠ Specific Heat Capacity Heat Capacity

  3. Weather: is described in terms of temperature, wind speed and direction, air pressure and moisture. Convection: heat transfer resulting from circulation. Convection & Weather

  4. Climate: refers to the main characteristics of an area’s weather. Ocean temperatures can have an effect on the climates of coastal communities. Oceans & Climate

  5. Oceans stay warmer through the fall and into winter than land masses. Oceans remain cooler through spring and into summer. Due to its high heat capacity:

  6. This keeps the climate of coastal areas from being extremely hot in the summer and extremely cold in the winter. This is called a Moderate Climate

  7. Occurs every 3-7 years The trade winds do not increase after having been slowed down. The waters are warmer than usual. Is responsible for changing rainfall patterns around the world. El Niño...

  8. El Niño ‘s effect on world weather systems

  9. These warm waters force the smaller ocean organisms (phytoplankton) to move deeper into cooler water. Fish and other animals that eat these organisms must follow.

  10. Often follows El Niño The equatorial trade winds increase allowing continuous upwelling of cooler water. Brings heavy rains to Australia, Africa and South America. Marine life flourishes as the upwelling bring nutrients for the phytoplankton. La Niña...

  11. Our weather patterns are rapidly changing due to the interaction of the Labrador Current and the Gulf Stream. Warm surface currents transfer tropical heat to the atmosphere and colder currents remove heat from the atmosphere. When the warm, moist air above the Gulf Stream blows over the colder water of the Labrador Current, it cools and condenses, producing fog. Ocean Current & Climate...

  12. Fog in Newfoundland

  13. Temperature fluctuations occur rapidly in NL due to our location between warm, tropical winds moving north and cold, arctic winds moving south. Local atmospheric temperatures depend on which of these prevail.

  14. Describe species found in the following freshwater environments. Be sure to include invertebrates, vertebrates, microorganisms and plants. Freshwater Environments: 1.Lakes and ponds 2.Wetlands 3.Rivers and streams 4.Estuaries • Refer to pages 90-93 Saltwater Environments: 1.Pelagic zone: the water column 2.Benthic zone: the ocean floor Living in Water...

  15. Species that are found in and around water systems can help us determine how healthy the water is (the quality of the water) Changes in the number of insects in a water system, for example, can tell us about the amount of pollution present in the water (the insects will always die first) Birds, plants, fish, and clams can also help us monitor freshwater systems. We call these species bioindicator species because they help to “indicate” the health of the water system These species are often the best way to determine water quality, because they are very sensitive to pollution. As soon as they are gone from a system, it indicates that the water could be polluted. Bioindicator species WRITE THIS DOWN

  16. Temperature: Low temperature means more dissolved oxygen. Dissolved Oxygen: levels should be ≥ 5mg/L Phosphates: levels should be < 10μg/L pH: level of acidity range should be 5 –8.5 Turbidity: how cloudy is the water Pollution Abiotic Factors that affect plant and animal distribution: WRITE THIS DOWN

  17. Upwelling: the vertical motion of water in the ocean by which subsurface water of lower temperature and greater density moves toward surface of the ocean bringing with it an abundance of nutrients. Salinity(marine) Ocean currents (marine) How do these factors affect productivity and species distribution in both marine and fresh water environments? Abiotic Factors that affect plant and animal distribution: WRITE THIS DOWN

  18. Activity 3.6 p. 108-111 “Water Health Test” Core Lab Activity

  19. For Example: 1.Confederation Bridge 2.Oil rigs 3.Sable Island gas development 4.Fundy tidal power Marine Technologies

  20. Technologies that have contributed to overfishing include: 1.Fish finding technologies such as radar 2.Factory freezer trawlers Bottom Trawling Overfishing... p. 105-6

  21. Affects on the marine environments include: 1.Pollution 2.Scouring the ocean floor 3.Marine habitat destruction 4.Release of foreign species in bilge water Offshore Oil Industry...p. 104

  22. The growing and harvesting of marine species in a controlled marine area. Usually built in sheltered areas such as a bay. May have accidental release of organisms and spread of diseases. Aquaculture...p. 106-7

  23. 1. Convection is the process of heat transfer in air. 2. The heat transfer causes weather as the air constantly moves up and down as winds blow it from place to place. 3. El Nino is caused by the decline in trade winds over several months. This event causes warm water to stay in place, and prevents colder water from upwelling. 4. La Nina is the opposite of El Nino; the trade winds increase causing continuous upwellings of cooler water. Answers p. 87

  24. 1. Specific heat capacity is the amount of heat it takes to increase the temperature of a substance. 2. Since water has a high specific heat capacity, oceans act as heat reservoirs in the winter, remaining warmer than nearby land and influencing local weather and, over time, climate. 3. Weather can be described in terms of temperature, wind speed and direction, air pressure, and moisture. 4. Weather describes short-term conditions in the atmosphere at a specific time and place. Climate describes weather conditions in a particular region over a long period of time, about 30 years. 5. Events such as El Nino can affect people in other parts of the world because changing winds and ocean currents result in different weather patterns along their path. When a part of the Pacific Ocean becomes warmer, then the currents that pass through that part become warmer, and carry that warmer water to other parts of the world. This process results in changes in temperature and rainfall. 6. The warm Gulf Stream Current passes by Great Britain. Due to the high specific heat capacity of water, the ocean around Britain stays warmer in winter resulting in mild, wet winters. Answers p. 89

  25. 7. Some currents are warm because they originate from the equator; others are cold because they originate from either the Arctic or Antarctic. 8. The colder Labrador Current acts as a heat sink for Newfoundland and Labrador in the summer, absorbing heat from the air, and moderating the temperature. 9. The cold Labrador Current and the warm Gulf Stream Current meet near Newfoundland and Labrador, very often creating fog. 10. Prince Rubert, BC, has a warmer climate because it is affected by the warm ocean currents nearby. The climate in Happy Valley- Goose Bay, in Labrador, is affected by the cold Labrador Current. Answers p. 89 continued

  26. 1. The two types of plankton are phytoplankton and zooplankton. Phytoplankton use photosynthesis to produce nutrients; zooplankton are tiny animals that eat phytoplankton. 2. The two types of plankton are the first link in the lake or pond food chain, and provide food for many organisms. 3. (a) A wetland is a lowland area that is saturated with water for part or all of the year. (b) Wetlands play an important role in the whole environment, acting as filters for pollutants, helping to prevent flooding, providing a resting point for migrating birds, and minimizing erosion. 4. Canada is home to one quarter of the world’s wetlands. 5. An estuary is a wetland that builds up where a river meets the ocean. Answers p. 99

  27. Answers p. 99 continued 7. Deep-ocean organisms use bioluminescence to find food, attract a mate, or scare away predators. 8. Answers may vary. Students may refer to the phosphates in fertilizers from farming, or phosphates in detergents, as being responsible. They may also point to manufacturers’ pollution.

  28. 1. Humans can affect water quality directly (point sources) or indirectly (non-point sources). 2. Human activities that affect the quality of water in a water system include the following: using water systems for dumping sewage, garbage, industrial waste, and waste water; landfill leaks; gas station storage containers; run-off from roads; pesticides and fertilizers from farmland and lawns; animal waste from parks and farms. 3. (a) Point source pollution comes from a specific area; non-point source pollution comes from many different sources. (b) point sources: landfill leaks; waste water from a factory or mill; oil spills; underground storage containers for gas stations; sewage systems; waste water treatment plants non-point sources: run-off from roads; pesticides and fertilizers from farms, lawns, and golf courses; and animal waste from parks and farms Answers p. 115

  29. 4. Point source pollution is easier to control because it can be traced back to the source of the contamination. Non-point source pollution comes from many different sources and is difficult, if not impossible, to trace. 5. Acid precipitation can affect people far away from where it falls by entering waterways and contaminating them, killing plants and animals. 6. Using oceans as garbage dumps means that garbage gets washed up on coastlines, beaches, and estuaries. Garbage that floats, such as plastic, can kill sea life. 7. Factory freezer trawlers, deep-sea trawlers, and radar technology allow fishers to catch enormous amounts of fish at a time, often with significant bycatch. 8. Students’ answers may include the following: If a species, such as the green crab, is suddenly added to an ecosystem, it can upset the ecosystem’s natural balance by eating a significant number of another species, without having a natural predator itself. If a species is suddenly taken away, the balance will also be upset as this species could be the food source for other species, or it could be a predator for anotherspecies. p. 115 continued

  30. 9. St. John’s, NL’s January temperature is affected by the warm Gulf Stream Current. 10. If people were allowed to go on the island all the time, they could frighten the birds away, damage nesting sites or food sources for the birds, or leave garbage that could harm the birds. 11. Pouring used oil along the side of the highway could kill local plants and animals, and could cause oil to eventually end up in the oceans through run-off where it would harm marine life. Answers p. 116-117

  31. 12. To determine if the river in my community were polluted, I would do the following: Step 1: Take a sample of the bottom sediment of the river, and check in shallow parts under gravel or rocks. Step 2: Examine the sediment with a magnifying glass. Step 3: Identify and record any bioindicator organisms I found. Step 4: Return the organisms to their natural habitat. Step 5: Calculate the total biotic index. 15. Seismic testing kills aquatic life, such as eggs and larvae, scares away fish, and changes migration patterns of whales. p. 116-117 continued

More Related