Water resources
Earth is called the "blue planet". How many % of its surface is covered by water?
Appr. 70 %
What is the force of evaporation?
The Sun
Name at least three oceans.
Atlantic, Indian and Pacific oceans.
Name the layers of the Earth.
Crust, mantle, outer core, inner core.
Where do earthquakes and volcanic eruptions usually occur?
At the border/edges of tectonic plates.
Where most of Earth's fresh water is stored?
In the glaciers, about 70 % of fresh water is stored in glasiers.
What is groundwater?
Groundwater is water stored in the soil and bedrock.
What are ocean currents?
These move warm or cold water around the globe and affect climate.
Explain some features of the Earth's outer core.
2200 km thick, mainly fluid iron and nickel --> causes the magnetic field
What is a tsunami?
If the centre of an earthquake with a magnitude greater than 7 is located under the sea and the edges of the plates move vertically in a rapid manner, the entire mass of water on top of the sea floor will begin to move. This can create a large tidal wave known as a tsunami.
What are the sources of fresh water? Name at least 4.
Glaciers, groundwater, ice in soil, lakes, rivers, bogs…
How groundwater is formed?
It is formed in gravel and sand regions when some of the water that falls on the ground is absorbed deep into the soil and accumulates underground. Groundwater occurs in coarse-grained soil types, such as gravel, where all the spaces between the grains are filled with water instead of air.
What are tides?
These regular rises and falls in sea level happen because of the Moon’s gravity.
What type of layer is the mantle of the Earth?
About 2900 km thick, elastic middle layer, 700-1,300 °C, convection currents of hot material.
What is formed to the border of convergent plates?
When lithospheric plates collide with each other, volcanoes and mountain ranges are formed. The collision of two lithospheric plates can also result in earthquakes. This collision zone has resulted in the formation of mountain ranges.
What is the meaning of water retention time in lakes?
How long does it take that all the water will change to the new in lakes.
Explain the key processes of water cycle: evaporation, condensation, precipitation.
Evaporation: Water turns into vapor due to heat.
Condensation: Water vapor cools and forms clouds.
Precipitation: Water falls as rain, snow, or hail.
What type of effects do the warm ocean currents have?
Causes rainy and warm weather to the coastal areas.
What are endogenous processes?
Caused by heat and magma moving inside Earth. Includes plate tectonics (plate movement), mountain building (orogeny), earthquakes and volcanic activity.
What is formed to the border of divergent plates?
In the Mid-Atlantic range, the Eurasian and North American plates diverge from each other at a speed of a few centimetres per year. When lithospheric plates diverge, new plate mass is created à mid-ocean ridge.
What causes drought?
Drought is caused by low precipitation relative to evaporation. Long periods of drought are influenced by a number of factors, including the Pacific El Niño phenomenon and climate change.
Explain the formation of rain.
Warm air holds more water vapor. Humid air rises and it cools. When the relative humidity reaches 100%, the dew point is reached, and water vapour starts to condense into tiny cloud droplets.
Condensation occurs around small dust particles, known as condensation centres --> water vapour turns into a visible cloud. Cloud droplets combine because of the colliding due to the movement of the air --> form raindrops, which fall due to gravity when those grow large enough
Why there are higher salinity in the oceans than in lakes?
Seawater is salty because it contains dissolved salts, mostly sodium chloride (table salt) which comes from:
•Rocks and soil: Rainwater, slightly acidic, slowly dissolves minerals from rocks on land.
•Rivers carry these dissolved salts into the ocean.
•Volcanic activity under the sea and on land also adds minerals.
•Over millions of years, these salts have accumulated in the oceans.
Rivers and lakes are less salty because:
•Their water is constantly replaced by rain and melting snow (which has no salt)
•Water from lakes and rivers flows out before salts can build up too much.
What causes the movements of tectonic plates?
Earth’s core is extremely hot because of:
This heat warms the mantle, causing magma to move in convection currents. Hot magma rises, cool magma sinks, creating a slow circular flow. These convection currents push and pull the tectonic plates floating on top of the mantle. As a result, the tectonic plates move.
Explain differences between shield and stratovolcanoes.
Shield volcano has gentle slopes, calmer eruptions, runny lava, made of lava layers, are located at the divergent plates where tectonic plates are moving apart from each other.
Stratovolcanoes have steeper sides, made of lava and ash layers, eruptions are explosive because of sticky magma, are located border of convergent plates.