Physical properties of air and water
Ringed seal – a mammal Arctic (black throated) loon – a bird
https://www.ecomare.nl/en/in-depth/reading-material/animals/seals/ringelrob/
http://t0.gstatic.com/licensed-image?q=tbn:ANd9GcTC6-MW35sunvBxrckrP3ED1ZKvtUf_aQEuzcprEGmfFNhquyqhENQg8ILPAJw_j32jkbyDh6k40IBR
How do the physical properties of air and water in respect to viscosity, buoyancy and thermal conductivity affect the energy requirements and demands of these two animals?
Physical properties of air and water
Complete the table to compare animal adaptations to the physical properties of air and water
The mammal: Ringed seal (Pusa hispida)
The bird: Arctic loon (Gavia artica)
Adaptatations
Adaptations
Buoyancy
Viscosity
Thermal conductivity
Specific heat capacity
Physical properties of air and water
Complete the table to compare animal adaptations to the physical properties of air and water
The mammal: Ringed seal (Pusa hispida)
The bird: Arctic loon (Gavia artica)
Adaptatations
Adaptations
Buoyancy
• Floating is difficult because seals are heavy but assisted by the large fat storage (blubber) under the skin which is less dense and makes the seal more buoyant.
*
Big airy feathers make wings very buoyant in air when flying
*
Buoyancy in water is aided by air sacs which can be inflated
and which keep the loon on the surface of water.
*
For diving, air sacs can be compressed
*
Denser, heavier bones than what birds normally have help
with reducing buoyancy to help with diving.
Viscosity
*
Heavy body weight so not much effort is needed when penetrating the viscosity of water.
*
Streamlined bodyshape reduces drag when swimming
*
Flippers to propel themselves forward
*
Powerful muscles in legs help with diving
*
Webbed toes for effective swimming with powerful strokes
*
Torpedo-like body shape (hydrodynamic)
*
In air perfectly sized wings help with uplift because viscosity is
lower
*
Fast flapping of wings helps with keeping loons in air
Thermal conductivity
*
Heat from the seal is easily conducted to water
*
A thick layer of blubber below the skin provides insulation
against the cold temeprature in water and on ice.
*
Thick dense body feathers help to keep the loon waterproof
*
Oil from oil glands in the skin acts as insulator
*
Thick plumage helps against cold air temperatures
Specific heat capacity
*
Water is used as a stable habitat
*
Ice caves can be used as lairs and nesting sites, because ice
insulates from outside temperature
• Water is a stable habitat due to the high specific heat capacity.
Extraplanetary origin of water on Earth
There is a lot of water on Earth – where does it have its origin?
Scientists believe that water sources on Earth are a consequence of asteroid collision, which have taken place in the first few 100 million years after Earth’s formation. These asteriods most likely also contained a lot of water in the form of hydrated minerals.
https://www.bbc.com/news/science-environment-37647049
Extraplanetary origin of water on Earth
Watch this video and answer the questions on your sheet.
https://www.youtube.com/watch?v=vjDnh7zfO98
https://www.sciencefocus.com/space/space-rocks
Extraplanetary origin of water on Earth
For water to stay on Earth (or any planet) after its appearance, it must be at the right temperature, as if the temperature is to high water would evaporate. If it were too low, all the water would freeze. The right temperature is therefore the one which allows water to stay at a liquid zone. The temperature is determined by the distance of a planet away from a star.
Goldilock zone
The habitable zone is often referred to as the Goldilock zone, after the Goldilock fairy tale
Extraterrestrial life and the presence of water
Planets in the Goldilock zone (the habitable zone) often show a presence of water or an atmosphere. However, this relationship does not automatically imply the existence of life.
.... and consequences for organisms
Cohesive forces of water molecules are caused by the hydrogen bonds between them. A single hydrogen bond is a weak intermolecular force of attraction, but the summative force of all hydrogen bonds is very strong.
Each water molecule hydrogen bonds with four others in a tetrahedral arrangement, making water cohesively “stick together”.