Water Chapter 5 (pg only)

70% of the Earth is covered in water. Our bodies are 55 to 70% water. We can only live a few days if potable water is not available. Potable water is clean drinking water. In developed countries, we generally have only temporary shortages and minor inconveniences, such as lawn watering restrictions. But in 3 rd world countries, safe drinking water is a luxury.

Why is water so valuable to life on Earth? Water is essential for plant and animal life. It dissolves and transports nutrients to living cells and carries away waste products. It evaporates to keep plants and animals cool. It dilutes contaminants and keeps pollution from being too bad in areas. It helps to create soil by breaking down rocks. Some plants and animals live in the water.

Water contains: Water is made of 2 hydrogen atoms and 1 oxygen atom. Gases tend to dissolve in water (like dissolved oxygen that we talked about last time). Water also contains small amounts of organic matter (living and dead material). It may also contain salts (like ocean water) or pollutants (hopefully not!)

Water—the universal solvent A universal solvent is a substance that dissolves or otherwise changes most other materials. Nearly every material will rust, corrode, decompose, dissolve, or otherwise yield to the presence of water. Water, then, generally has something in it…some minerals it has dissolved along the way. Some minerals make your drinking water taste good. Other minerals (or too much of them) can make the water taste bad.

Freshwater vs Salt Water Freshwater contains little to no salt. Rivers, streams, creeks, and most lakes are all freshwater. Saltwater has heavy concentrations of salt. Oceans and a few inland lakes are salt water. Tidewater is ocean water that flows up the mouth of a river when the tides are high.

Twitter Time! Make up 5 Tweets about these notes. Remember, Tweets can only have 140 characters in them. Hashtags are fine… the funnier (but appropriate!) the better! This is an individual OR a partner thing. However, if you do it in partners, then you still have to do 5 per person. So a group of 2 would have to do 10 Tweets. Got it?