Geography Unit 1

Question	Answer
Identify the three main layers that make up the Earth.	Crust, Mantle and Core.
Briefly explain what happens when two plates are pulled apart.	The core heats the molten rock located in the mantle to create a convection current. The heated rock rises to the Earth's surface. Here the convection current moves the tectonic plates in the crus. Molten rock cools and flows back to the core to be reheated.
Give two differences between continental and oceanic crust.	Continental crust is thicker but less dense than oceanic crust.
What are the three main types of plate boundaries?	Destructive, Conservative and Constructive.
Give an example of a destructive plate boundary.	Nazca Plate or South American Plate.
Give an example of a Constructive Plate boundary.	Eurasian or North American Plate.
Give an example of a Conservative Plate boundary.	San Andreas Fault or California.
What is Subduction and why do only oceanic plates subduct?	Where one plate meets another and one goes down into the mantle. Continents are made of rocks that are too buoyant to be carried much farther than about 100 km deep. So when a continent meets a continent, no subduction happens.
Where are Shield volcanoes and Composite volcanoes found?	Shield volcanoes are found on constructive plate boundaries and composite volcanoes are found on destructive plate boundaries.
How are Shield and Composite volcanoes formed ?	Shield volcanoes are formed by eruptions of thin, runny lava which takes a while to solidify. Composite volcanoes are formed by eruptions of vicious, sticky lava and ash that doesn't flow very far.
What physical characteristics does a Shield and Composite volcano have ?	Shield has gently sloping sides and a wide base. Composite are made up of layers of thick lava and ash.
Which magma does shield and composite contain ?	Shield contains basaltic magma which is very hot and with a low silica and gas content. Composite contains andesitic magma which isn't as hot but contains lots more silica and gas.
What does the Richter Scale measure ?	It measures the energy released by an earthquake.
What does the Mercalli Scale measure ?	It measures the effects or impacts.
Why do some earthquakes have a greater impact than others ?	Some earthquakes are more powerful. Some places are more vulnerable for example (less money to build earthquake proof homes and train people what to do in an earthquake).
Give a named example of an earthquake.	The Kashmir earthquake 2005 or The Loma Prieta earthquake, California 1989.
What is a pyroclastic flow ?	Pyroclastic flows are high-density mixtures of hot, dry rock fragments and hot gases that move away from the vent that erupted them at high speeds.
What can help predict when an earthquake or volcano is coming ?	Animals and birds moving away from the area. Increased gas emissions. Increased soil temperature. The volcano swelling. An increase in small earthquakes. Water in ponds getting warmer.
What are two primary impacts of the Haiti earthquake ?	Injured and dead trapped under rubble. People sleeping in the streets. Mortuaries unable to deal with the high numbers of dead and the graves needing to be dug. Phone and power lines down. Streets blocked by huge piles of rubble from collapsed buildings.
How can a building be strengthened against earthquakes ?	Deeper foundations. Making foundations from rubber and steel which can move slightly. Very strong framework especially for skyscrapers. Strengthening walls. Reinforced gas and water pipes so they cannot break. Installing a band of concrete at roof level to stop walls falling outwards.
What are the primary and secondary impacts of the Montserrat volcanic event?	Primary impacts include the destruction of its capital city, Plymouth (it became covered in ash). The destruction of most of the island's crop was due to the ash and evacuation of people. Another primary impact is the forests were destroyed by the fires caused by the gases from the volcano. Secondary impacts are that half of the original population left the island, which had an affect on the economy of the island as well as socially. It had become a ghost town and instead was once a popular place.
What are ice cores ?	They are cylinders of ice obtained by drilling through glaciers 3km deep in ice up to 500,000 years old.
What are Milankovitch cycles ?	It is where the Earth's orbit changes a small amount once every 100,000 years.
What are some natural causes of climate changes?	The amount of energy radiated from the sun changes over an 11year period. Volcanic eruptions pump ash dust into the atmosphere causing a cooling effect. Large asteroid collisions can cause cooling as material blocks out the sun. Ocean current changes can cause cooling and warming.
What were two impacts on people during the little ice age ?	Crops did not grow well which meant less productivity and less food for people. The winters were very cold and the summers were short.
What could be the causes of the little ice age ?	Fewer sun spots, volcanic ash in the atmosphere. It was unlikely to be caused by humans as there was not enough people or industry to cause climate change.
Why did Megafauna become extinct ?	They couldn't adapt to the warmer climate and became extinct. Hunting by early humans could also have helped with their extinction.
What are some sources of evidence about climate change ?	Diaries, newspapers and paintings. Tree rings are thinner during cold periods.
State two natural causes of climate change in the past.	Orbital changes, Solar outputs, Volcanic activity and Asteroid collisions.
What is one human activity that is thought to have led to an increase in greenhouse gases?	CO2 and methane are greenhouse gases linked to human activity. Combustion of fossil fuels.
Why is more carbon dioxide produced ?	There is more industry. More energy is required so more fossil fuels are burned. More oil is burned due to increase in transport. Land is needed so there is deforestation. More methane is produced because there is more demand for meat and this leads to more farm animals.
What are two possible challenges for people in the UK that could occur from a global temperature rise of 2oc ?	Possible flooding of towns on the coast. Increased threat of drought as rainfall becomes less reliable.
What factors impact on the UK's climate ?	Latitude affects how much sun the UK gets and how strong it is during the different seasons. The Drift keeps the UK warmer than other places of the same latitude.
What are some possible changes in the UK's climate ?	Average temperature rise. Less predictable rainfall patterns with drier summers. Changing seasons.
What are two environmental impacts of climate change in the UK ?	Sea level rise will lead to coastal land and increased erosion. Risk of low lying cities flooding. London. More severe storms and longer summer droughts.
What are two economic impacts of climate change in the UK ?	Hotter summers could mean more people having holidays here instead of traveling abroad (less air travel over seas). Housing design might need to be altered so that less water is wasted and higher temperatures are dealt with.
What are two environmental impacts of climate change in Bangladesh ?	River flooding would worsen from heavier rains and sea level rise. Tropical storms could become even more frequent and may move further inland, causing more damage.
What are two economic impacts of climate change in Bangladesh ?	Increased flooding will increase the spread of water-borne diseases. Coastal flooding damages farmland by making the soil too salty to grow crops.
What is an ecosystem ?	A grouping of plants and animals that interact with each other and their local environment.
What is a biome ?	A large ecosystem - a grouping of plants and animals over a large area of the Earth.
What is a Deciduous biome ?	They have high rainfall and there are seasonal variations in the Sun's rays. Trees lose their leaves in the cool of winter.
What is a Coniferous biome	They have higher latitudes where the Sun's rays are weak. Trees are adapted to the cold with needle like trees.
What is a Tundra Biome ?	The Tundra is located in the Arctic circle. The sun gives little heat and there is little rainfall. Only tough, short grasses survive.
What is a Desert biome ?	They are close to tropics of Cancer and Capricorn. Here hot air sinks down to the Earth's surface and the Sun's rays are concentrated making it very hot in the day.
What is a Tropical biome ?	They are mostly found on either side of the equator. The temperature is hot and there is heavy rainfall.
What are the reasons for rainforest destruction ?	Timber needed for buildings, furniture and fuel. Creation of agricultural land for growing crops or grazing animals. Mining and quarrying of minerals for construction, industry, jewellery making. Transport routes. Building human settlements. Building dams and power stations to provide power.

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