a1.1.6 - physical properties of water Flashcards
define physical property
a measurable behavior or characteristic of matter that exists without the matter reacting or interacting with other things
list physical properties of water that are consequential for animals in aquatic habitats
- buoyancy
- viscosity
- thermal conductivity
- specific heat capacity
outline the cause and effect of buoyancy
cause:
- an upward force applied to an object that is immersed in a fluid
effect:
- if the buotant force of the fluid is greater than the object’s weight, the object will float
outline the cause and effect of viscosity
cause:
- the amount of friction the molecules of a liquid experience as they flow over each other
effect:
- a thick fluid is more viscous and a thin fluid is less viscous
compare viscosity of air to water to blood
- air < water < blood
- molecules in air have little friction as they flow over each other, so air is not viscous
- molecules in water can form hydrogen bonds with each other, increasing the friction and viscosity
- cells and dissolved solutes in blood cause even more friction as the blood flows, increasing viscosity
define thermal conductivity
a measure of a material’s ability to move heat across a temperature gradient
compare less conductive to more conductive materials
less conductive:
- heat slowly moves through the material
- better at insulation and preventing heat loss
more conductive:
- heat rapidly moves through the material
- better for absorbing and transferring heat
outline a consequence to life of the thermal conductivity of air and water.
marine mammals are exposed to both air and water. the animal will lose more body heat to the environment when in water than in air because water rapidly absorbs and removes heat from the body. as a result, these animals have large layers of blubber which insulate their body heat sources (muscles) from the environmental. fat is less conductive of thermal energy than water, so the animal is able to retain more body heat than it would be able to without the blubber.
define specific heat capacity
the quantity of heat needed to raise the temperature of a chemical per unit mass
describe why water has a high specific heat capacity
water’s high heat capacity is caused by its numerous hydrogen bonds. each individual “bond” is weak, but there are so many of them that collectively a lot of energy must be added to break them all.
state two benefits to life of the high specific heat capacity of water.
as a result of its high specific heat capacity, water heats up or cools down very slowly. this provides for a stable internal environment and habitat of living things.
outline a benefit to life of water’s high specific heat capacity.
because living body’s contain a lot of water, body temperature is slow to fluctuate when environmental temperatures change. water’s high specific heat capacity helps body temperature rise and fall slowly when external temperatures becomes very hot or cold.
compare the physical properties of water to those of air
water:
- greater buoyant force
- greater viscosity
- greater thermal conduction
- greater specific heat capacity
air:
- lower buoyant force
- lower viscosity
- lower thermal conduction
- lower specific heat capacity
describe how the black-throated loon (Gavia arctica) interacts with the physical properties of water in their habitat.
buoyancy in water allows the bird to stay afloat without expending a lot of energy, however when flying through air the bird must expend energy to stay aloft. air is not viscous, so the loon can easily move through it when flying. the loon doesn’t lose as much body heat to the air because air has low thermal conductivity. however, because the air has a low specific heat, its temperature changes as rapidly.
describe how the ringed seal (Pusa hispida) interacts with the physical properties of water in their habitat.
buoyancy in water allows the seal to stay afloat without expending a lot of energy. however, the water is viscous, so the seal has adaptations for streamlining as it swims through it. water has a greater thermal conductivity than air, so the seal needs to insulate itself with blubber to maintain body temperatures. however, because the water has a high specific heat, the temperature of the water does not change as rapidly as the air around it, providing habitat stability for the seal.
