1 – 2 sentences why each of the following unique properties of water is important to living things

Water is the universal solvent:

Water is less dense as a solid than as a liquid

Water molecules are attracted to one another (cohesion)

Water molecules are attracted to other substances (adhesion)

1. Water being the universal solvent is important for living things because it allows for various essential molecules and ions to dissolve in water, facilitating biochemical reactions and transporting nutrients and waste products within organisms.

To understand this concept, it is important to know that water is a polar molecule, meaning it has a partial positive charge on one end and a partial negative charge on the other end. This polarity allows water to interact with charged or polar molecules, breaking them apart and surrounding the individual molecules with water molecules, dissolving them in the process.

2. The property of water being less dense as a solid than as a liquid is critical for living things because it allows ice to float on water bodies. This prevents complete freezing of bodies of water and enables life to survive beneath the ice during cold seasons.

To grasp why water expands when it freezes, knowledge of the structure of water is necessary. Normally, water molecules are constantly moving and forming and breaking weak hydrogen bonds with one another. However, when water cools and freezes, the molecules form a highly ordered arrangement, with each water molecule forming stable and rigid hydrogen bonds with four neighboring water molecules. This spacing creates a hexagonal lattice structure, causing ice to be less dense and float on top of liquid water.

3. Cohesion, which is the attraction between water molecules, is vital for living things as it enables water to be transported against gravity in plants, assists in the movement of blood in animals, and allows small insects to walk on water surfaces.

Understanding cohesion requires the knowledge that water molecules are attracted to each other due to their partial positive and negative charges. These attractions create hydrogen bonds between adjacent water molecules, forming a continuous network throughout the substance. This cohesive property gives water a high surface tension, allowing it to form droplets, resist external forces, and move upwards in narrow spaces due to capillary action.

4. Adhesion, the attraction of water molecules to other substances, is important for living things because it enables water to stick to surfaces and facilitates capillary action, helping plants draw water from their roots and distribute it to their leaves.

Adhesion occurs due to water's polar nature and its ability to form hydrogen bonds. When water comes into contact with a surface, such as a plant cell wall or a glass tube, the water molecules are attracted to the molecules of the surface, leading to adhesion. This property allows water to "climb" upwards through narrow channels, against the force of gravity, aiding in the transport of water and nutrients in plants.