Lesson 3.01 Properties of Water

• Introduction
• Learn
• Try It
• Task

Introduction

In Unit 2, you learned about factors that limit a population's ability to grow. One of the major factors that limits an ecosystem's carrying capacity and controls a population's ability to grow is the amount of available water.

Just like food, water is essential for life to exist on Earth. All organisms rely on water to help carry out physiological processeslife processes. In some organisms, water makes up 90% of their body. The human body consists up to 60% water. In newborns, it is about 78%.

Water serves many essential functions in humans, such as

• building material for cells;
• regulating internal body temperature;
• transporting nutrients;
• assisting in flushing waste from the body;
• acting as a shock absorber for the brain, spinal cord, and fetuses
• forming saliva which helps with digestion;
• lubricating joints.

Read The water in you from the USGS Water Science School for more information.

The average human can only go about three hours without water compared to several weeks without food.

Without water, life on Earth would not exist. It is important that organisms have access to pollution-free freshwater. In this lesson, you will explore the properties of water and how these properties make water essential for all life.