Other characteristics of pure water are that it is colorless and tasteless . In most of our homes, it is easy to take water for granted. After all, water is the most abundant substance on earth. Think about the difficulties you might have experienced when you forgot to bring enough water with you when camping, or consider the plight of farmers during a drought or the appearance of your lawn when you've forgotten to water for a few days during July. Such situations demonstrate that our need for water commands our attention in many ways.
Water is vital to life of all kinds.
On a biological level , water is used to transport materials into and out of our cells. Look back over the background information for air. Our lungs must be wet in order for oxygen to be taken out of the air and into our bloodstream. Water is also used to remove waste from the cells of our body. The importance of water for life is demonstrated by the fact that humans can do without food for several weeks, but we could not survive without water for more than a few days.