BIOL 2140 Lecture Notes - Lecture 2: Viscosity, Heat Capacity, Tonicity
Document Summary
Pure water becomes a solid below 0 degrees celsius and vapor above 100 degrees celsius. When water contains dissolved compounds, such as salts, it"s freezing temperature drops below 0 degrees celsius. Water has a high specific heat; which is the energy required to raise water temperature by 1-degree celsius. This makes water resistant to changing states; helps prevent water bodies from freezing solid during the winter. Water is at its highest density at 4 degrees celsius. Above and below 4 degrees celsius, the density of water decreases. Ice is less dense than liquid water, so it floats on the surface. As a result, the lower layers of lakes and ponds are typically ice freeing during winter. Some body tissues are more dense than water (ex. Organisms have developed many adaptations to cope with their tendencies to sink or float. Viscosity: the thickness of a fluid that causes objects to encounter resistance as they move through it.
