What is the most incredible and valuable substance on Earth? Yes, it’s water.
Most school-aged children know that the majority of the Earth’s surface is water. It isn’t until those children get a little older that they find out that 97% of the Earth’s water is salt water in the oceans (97%). Not only that, so much of the world’s water is frozen.
Any map or globe shows so much water, yet actually less than 1%A is available as non-frozen, fresh water.
Water is seen on our Earth in oceans,lakes, rivers, streams, and in rock layers underground called aquifers. A large amount of water is also found in the bodies of living things.
Water is the only compound that commonly exists in all three states (solid, liquid, gas) on Earth.
It is the unique properties of water that are a major factor in our planet’s ability to sustain life.
Here are some additional properties of water:
1) Many substances will dissolve in water. This is why water is often called the universal solvent.
2) Water absorbs heat energy without large changes in temperature. Large bodies of water act to moderate the climate of surrounding areas by absorbing heat in summer and slowly releasing that heat in the winter. This explains why the climate near large bodies of water is slightly milder than areas without large bodies of water.
3) Water expands when it freezes, which is different than other substances. Ice is less dense than liquid water.
4) Water has a wide range of temperatures.
5) Water exhibits high surface tension.
6) Individual water molecules attract other water molecules like little magnets as the slightly positive portion of a water molecule is attracted to the slightly negative portion of an adjacent water molecule. In this way water molecules “stick” together.
Water shapes our environment by physically and chemically weathering rock and soil and transporting sediments. Through physical weathering, freezing water can break rock without any change in the minerals that form the rock. This usually produces small particles and sand. Chemical weathering also takes place as water with dissolved gases and other chemicals causes the minerals in rocks to deteriorate.
Water was the determining factor in where human settlements were established and how they developed. The first human settlements were established by springs, rivers, and lakes. Reliable fresh water sources and irrigation systems, enabled civilizations to grow and flourish. As cities grew, different techniques were developed to collect water such as tunnels, aqueducts, wells, pumps,cisterns,and reservoirs.
In addition to water being essential for the human body, water’s importance is critical for agriculture. Crops that cannot be planted near natural sources of water must be watered by reliable irrigation systems.
Water is an important natural resource not only for the reasons mentioned, but also as a resource used in generating power. Water is used in hydroelectric power plants. As the water is heated and turned to steam, the steam is then used to move turbines that generate electricity.
Water is essential to life and to agriculture and industry. It is a precious resource that surrounds continents and serves as transportation routes for commerce and travel. It is the most incredible and valuable substance on Earth.
