2 Soda and Density Differences DEMO Will the diet soda sink or float? Will the regular soda sink or float?WHY!?!?
3 The Physics of waterSeawater’s chemical reactions affect how life functions in the oceans.Water properties not only affect life processes of marine organisms and their survival, but also humans in the ocean as well (divers)
4 1) Heat and Heat Capacity Heat: kinetic energy in random movement, or vibration, of atoms and molecules in a substanceFaster molecules = more heatBased on the speed of vibration and quantity of these molecules (total heat energy)
5 Temperature: measures how fast the molecules vibrate Two most common temperature systems are Celsius and Fahrenheit.Celsius most used in science because it measures water’s physical properties
6 Heat Capacity: amount of heat energy required to raise a given amount of substance by a given temperature.-Measure by: 1 gram substance to raise 1⁰C-expressed by the number of calories needed-Water has highest heat capacity; takes longer; water can absorb more or less heat with little temperature changeThis effects Earth’s climate and weather.
7 2) Water Temperature and Density Water cools, becomes denser. 39.8⁰C = max densityBelow this, water freezes where it becomes less denseIce does not form all at once at the freezing point; continuously crystallizes until all liquid is solid which produces:Non-sensible heat: change in heat energy that cannot be sensed with a thermometer.Latent heat of fusion: non-sensible heat lost when water goes from liquid to solid stateSensible heat: can actually sense in a thermometer
8 3) Latent Heat of Vaporization The heat required to vaporize a substanceIt takes more heat to vaporize water than to freeze it WHY?Because when water freezes only some of the hydrogen bonds break.When it vaporizes, all the hydrogen bonds must break, which requires more energy
9 4) Thermal Inertia Tendency of water to resist temperature change Thermal equilibrium: water cools at about the same rate as it heatsImportant to life because:Seawater is the global thermostat; prevents major temperature swings (drastic in night and day summer and winter)Without thermal inertia, many of the organisms on Earth could not be able to survive the drastic temp changes that occur each night.
10 5) Ocean Water DensitySeawater density varies with salinity and temperature-causes seawater to stratify: form layersDense water is heavy and sinks below less dense layers. 3 density layers:1) Surface zone: 2% of the oceans volume; Extends from top to about 100 m2) Thermocline: separates surface zone from the deep zone. Only temperature or salinity to exist. 18% of the oceans volume.3) Deep zones: lies below the thermocline. Very stable region of cold water starting deeper than 1,000 m; shallower in polar regions; zone makes up about 80% of ocean’s volume.
11 How water Physics Affect Marine Life 1) LightWater scatters and absorbs light. When light reaches the water’s surface, some light penetrates, but, depending on the sun’s angle, much may simply reflect back out of the water.Light reflects off light-colored suspended particles.Dark colored particles and algae absorb some lightWater molecules absorb the energy, converting light into heatWater absorbs colors at the red end of the spectrum more easily than at the blue end
12 Two zones with respect to light penetration Photic Zone: where light reaches. Has two subzones:- Euphotic Zone: upper shallow portion where most biological production occurs.- Dysphotic Zone: where light reaches, but not enough for photosynthetic life2) Aphotic Zone: makes up the vast majority of oceans. Light does not reach and only fraction of organisms live here
13 2) Temperature: -Marine organisms live in a much less challenging environment with respect to temperature range ectotherm: organism’s internal temp changes with seawater temp (cold-blooded) endotherm: organisms internal temp varies, but remains warmer then the surrounding water Homeotherm: internal temp relatively stable. (warm-blooded) (marine mammals and birds) -Temperature affects metabolism: high temp= more energy releasing chemical processes -Metabolic rate remains the same regardless of external temperature allowing them to live in a variety of habitats
14 3) SoundTravels through warm water faster than cool, but travels faster in deep water due to pressure.Sound bounces off suspended particles, water layers, the bottom and other obstacles.Sound travels much farther thru water than light does.Sound is eventually absorbed by water as heatMarine animals use echolocation: enables them to sense an object’s size, density, distance, and position underwater.
15 4) Pressure -Hydrostatic pressure: pressure exerted by water; i. e 4) Pressure -Hydrostatic pressure: pressure exerted by water; i.e. the weight of water. - at 10 m hydrostatic pressure is equal to atmospheric pressure - at 10 meters: total pressure is 2 bar- 1 bar atmospheric pressure and 1 bar from hydrostatic pressure - A marine organism living at 10 m experiences twice the pressure present at sea level. Pressure increases 1 bar for each additional 10 m - HYDROSTATIC PRESSURE DOESN’T AFFECT MARINE ORGANISMS BECAUSE IT IS THE SAME INSIDE THE ORGANISM AS IT IS OUTSIDE. (pressure does not crush or harm marine organisms!)
16 5) Size and Volume:Increase size=Increase volumeHigh surface to volume ratio is important for cell function.Bigger cell= lower surface to volume ratio, which means that there is less relative area through which to exchange gases, nutrients, and waste.6) BuoyancyArchimedes' Principle: an object immersed in a gas or liquid is buoyed up by a force equal to the weight of the gas or liquid displaced.This means that marine organisms don’t have to spend a lot of energy balancing their own weight.Allows some organisms to exist simply by drifting and never coming in contact with the bottom
17 7) Movement and Drag -Marine organisms avoid sinking by hairs, spines, etc. increasing their drag and help them resist sinking. Some have buoyancy adaptations . -Some organisms need to overcome drag. To do this: move or swim slowly, excrete mucus so they can “slip” through water, or have a shape that reduces drag (streamlining) 8) Currents -Drifting provides several advantages: -Disperses organisms into new habitats, ensuring survival -Take organisms into nutrient rich areas, reducing competition for resources.
18 Daily Quiz #2Explain three (3) physical properties of water and how they affect marine life.SoundPressureLightDensityTemperature