Water
Water
Properties of water Water is made up of two elements, hydrogen and oxygen. Each molecule of water is made up of two hydrogen atoms bonded to a single oxygen atom so its chemical formula is H2O. It is the most abundant compound and covers about 70% of the Earth’s surface. Water can exist in a variety of states: • in a solid state when it is below 0°C and is frozen and forms ice • in a liquid state when it is at temperatures of between 0°C and 100°C and forms a transparent fluid • as an invisible gas when it is over 100°C and forms water vapour. Water is the only common substance that appears in these three forms naturally on the surface of the Earth. The word water usually refers to water in its liquid state. It is essential for all life on Earth. Water makes up 55% to 78% of the human body. Video demonstrating states of water present in domestic life: http://en.wikipedia.org/wiki/File:Water_Video.webm
Copyright for all materials remains the property of the authors, but you may use it freely for
educational purposes.This site hosted by Geohubliverpool.
“Geology gave us the
immensity of time and
taught us how little of it our
own species has occupied.”
― Stephen Jay Gould,
Water droplet
Invisible water vapour condenses to form
visible clouds of liquid water droplets.
Frozen water in the form of an ice
cube. The white zone in the centre
is the result of tiny air bubbles
Water in three states: liquid, solid
(ice), and gas (invisible water vapour in
the air). Clouds are accumulations of
water droplets, condensed from
vapour-saturated air.
Pictures from Wikipedia
The water cycle
Earth's water changes forms between liquid (rain), solid (ice), and gas (vapour) and also moves on the Earth’s surface, above the surface and in the Earth. The diagram shows the water cycle and the links between the three forms of water together with the processes that occur when they change from one form to another.
Picture from the United States Geological Survey (USGS)
Processes in the water cycle
Key terms used to describe the main processes in the water cycle are: evaporation, condensation, transpiration and precipitation. These terms are explained in an interactive water cycle for schools that is available from the United States Geological Survey at: http://water.usgs.gov/edu/watercycle-kids-beg.html (At this USGS site there are versions of this interactive water cycle available at beginner, intermediate and advanced levels)Groundwater
Water can be found in different places within the water cycle. Some water falls on the Earth’s surface as rain and may flow into rivers and back into the sea. Most rainfall will soak into the soil where it may be taken up by plants or it may soak further into the ground (a process called infiltration) and become groundwater. This water is important because groundwater makes up about 70% of the world’s freshwater. Porous rocks have lots of little spaces between the bits that make up the rock, the rock grains, allowing them to hold water like a sponge. Permeable rocks allow water to pass through them and gravity continues to pull the water down until it reaches a layer of rock that is impermeable (it does not allow water to pass through it). When this happens the permeable rock can get saturated or full of water. As the amount of water builds up the level of the water in the rock gets higher – this level is called the water table. The water table roughly mirrors the slope of the land's surface and is always higher after prolonged rain and lower after long periods without rain. In the diagram below a well is shown penetrating the water table. Where the water table is close to the surface, wells can be a very convenient method for extracting water.
Picture from Wikipedia
Underground rocks which store water in this way are called
aquifers. The map shows the distribution of the principal
aquifers in the British Isles.
Picture UK Groundwater Forum
Useful image gallery
A gallery containing illustrations from the UK Groundwater Forum's book ‘Groundwater - our hidden asset’ is accessible at: http://www.groundwateruk.org/Image-Gallery.aspx (The images were created by Chris Wardle of the British Geological Survey and the copyright is vested in the Natural Environment Research Council (NERC). On behalf of NERC, BGS confirms that permission is freely granted for their use in academic and non-commercial publications or presentations provided the wording "UK Groundwater Forum" is included on the image.)
Water
Funded by:
Created by ESTA members: Tracy Atkinson, John Reynolds, Stewart
Taylor, Geoff Selby-Sly, Maggie Williams, Peter Williams
Copyright for all materials remains the property of the authors, but you may use it freely for
educational purposes.
Water
Properties of water Water is made up of two elements, hydrogen and oxygen. Each molecule of water is made up of two hydrogen atoms bonded to a single oxygen atom so its chemical formula is H2O. It is the most abundant compound and covers about 70% of the Earth’s surface. Water can exist in a variety of states: • in a solid state when it is below 0°C and is frozen and forms ice • in a liquid state when it is at temperatures of between 0°C and 100°C and forms a transparent fluid • as an invisible gas when it is over 100°C and forms water vapour. Water is the only common substance that appears in these three forms naturally on the surface of the Earth. The word water usually refers to water in its liquid state. It is essential for all life on Earth. Water makes up 55% to 78% of the human body. Video demonstrating states of water present in domestic life: http://en.wikipedia.org/wiki/File:Water_Video.webm
“Geology gave us the immensity of time
and taught us how little of it our own
species has occupied.”
― Stephen Jay Gould,
The water cycle
Earth's water changes forms between liquid (rain), solid (ice), and gas (vapour) and also moves on the Earth’s surface, above the surface and in the Earth. The diagram shows the water cycle and the links between the three forms of water together with the processes that occur when they change from one form to another.
Water droplet
Frozen water in the form of an ice
cube. The white zone in the centre
is the result of tiny air bubbles
Water in three states: liquid, solid
(ice), and gas (invisible water vapour in
the air). Clouds are accumulations of
water droplets, condensed from
vapour-saturated air.
Invisible water vapour condenses to form
visible clouds of liquid water droplets.
Pictures from Wikipedia
Picture from the United States Geological Survey (USGS)
Processes in the water cycle
Key terms used to describe the main processes in the water cycle are: evaporation, condensation, transpiration and precipitation. These terms are explained in an interactive water cycle for schools that is available from the United States Geological Survey at: http://water.usgs.gov/edu/watercycle-kids-beg.html (At this USGS site there are versions of this interactive water cycle available at beginner, intermediate and advanced levels)Groundwater
Water can be found in different places within the water cycle. Some water falls on the Earth’s surface as rain and may flow into rivers and back into the sea. Most rainfall will soak into the soil where it may be taken up by plants or it may soak further into the ground (a process called infiltration) and become groundwater. This water is important because groundwater makes up about 70% of the world’s freshwater. Porous rocks have lots of little spaces between the bits that make up the rock, the rock grains, allowing them to hold water like a sponge. Permeable rocks allow water to pass through them and gravity continues to pull the water down until it reaches a layer of rock that is impermeable (it does not allow water to pass through it). When this happens the permeable rock can get saturated or full of water. As the amount of water builds up the level of the water in the rock gets higher – this level is called the water table. The water table roughly mirrors the slope of the land's surface and is always higher after prolonged rain and lower after long periods without rain. In the diagram below a well is shown penetrating the water table. Where the water table is close to the surface, wells can be a very convenient method for extracting water.
Underground rocks which store
water in this way are called
aquifers. The map shows the
distribution of the principal
aquifers in the British Isles.
Picture from Wikipedia
Picture UK Groundwater Forum
Useful image gallery
A gallery containing illustrations from the UK Groundwater Forum's book ‘Groundwater - our hidden asset’ is accessible at: http://www.groundwateruk.org/Image-Gallery.aspx (The images were created by Chris Wardle of the British Geological Survey and the copyright is vested in the Natural Environment Research Council (NERC). On behalf of NERC, BGS confirms that permission is freely granted for their use in academic and non- commercial publications or presentations provided the wording "UK Groundwater Forum" is included on the image.)
