Chapter Three Reading Journal

Questions:

What main thing can account for the properties of water that make it so conductive to life?
- Hydrogen bonding is responsible for the special qualities that water possesses. Hydrogen bonding is responsible for the adhesion and cohesion of water that makes the transport of water within plants so successful. Hydrogen bonding is also what makes water able to maintain relatively consistent temperatures and keeps it from evaporating as quickly as most liquids. This is also a main reason that water makes such a great solvent.

What is PH?
- PH is an expression that helps us see the concentration of H+ and OH- ions in a substance. The lower the PH the higher the concentration of H+ ions and the higher the PH the more OH- ions are present. The PH scale only ranges from 1-14 because it is based on logarithms. A PH of 7 is neutral.

What is a buffer?
- A buffer is something that is able to balance the PH of a substance. A buffer is able to attach some of the H+ ions to itself as well as adhere OH- ions to itself. Buffers are able to do this by being a substance that has an acidic portion and basic portion balancing the excess of either H+ or OH- ions. Buffers within living things are very important for example the presence of buffers within human blood keeps blood at a PH of 7.4 and prevents it from changing PH quickly.

Facts:
- Water is a polar molecule making it conductive for hydrogen bonding with other water molecules
- Cells are made up of 70-95% water
- Water is able to moderate air temperature by absorbing heat from the air surrounding it and then releasing back into the air at cooler times during the day
- The fact that ice is less dense than water allows marine creatures to survive even when a body of water freezes because it does so only at the top layer
- Water’s ability to be a solvent makes it conductive to life especially within cells





This shows the crystal like structure that water forms when it freezes. The fact that the molecules spread out when frozen makes water less dense in its solid state. This is structure is very important to organisms that live in bodies of water. Since the ice is less dense than the rest of the water it floats to the top allowing life to continue under this top layer of ice if this were not the case winter would kill off creatures that live in bodies of water.

Summary:
Water’s polarity results in hydrogen bonding. The behaviors of hydrogen bonding gives water many of its special properties. Water is so conductive to life because of its ability for cohesion, its control of temperature within cells and in large bodies of water, the crystal structure formed when frozen (explained above), and its many uses as a solvent. Water and other liquids are greatly affected by their PH levels, which are determined by the amount of H+ ions. Industrial pollution creates great risk to the planets health by making the ocean and other bodies of water more acidic.