Unit 4energy From The Sun

Unit 4

Energy from the Sun (Global System)

Sun: closest star to Earth - directly or indirectly energizes everything on Earth - Sun’s energy (E) sustains life on Earth o 1. plant trap solar E to produce food 6CO2(g)+6H2O(l)---(solar E/ chloroplasts)-C6H12O6(s)+6O2(g) o 2. Fossil fuels are plant remains from millions of years ago o 3. Solar E is trapped by atmospheric CO2 and water vapour makes Earth inhabitable o 4. solar E creates weather Chapter 1: -

Life on Earth began in the oceans single-celled organisms, latermulticellular organisms had to have a way of obtaining E radiant E from Sun cannot be directly used as an E source for organisms organisms need a storable chemical E source organisms developed a way to convert solar E to chemical E organisms that provide for their own needs are called Autotrophs: selfnourishing plants and algae (protists) later, other organisms (orgs) evolved that consumed the autotrophs (getting their chemical E from them), called heterotrophs (obtain E from others) BUT ALL life on Earth depends on autotrophs (Plants and algae) being able to convert solar E to stored chemical E in the form of glucose

Photosynthesis: Photo:light Synthesis: putting together to make larger, more complex substances Def: Process by which green plants and cholophyll containing protists put together CO2 and H2O to from carbohydrates and oxygen On Earth, 3 things became of photosynthesis: 1. Organisms that can take in radiant E and convert it to stored chemical E 2. Oxygen 3. Orgs that have evolved to use stored chemical E

How organisms use stored chemical E = glucose 1. organisms take in (ingest) glucose 2. Chemical reactions in the body of the organism gradually release E into a useable form for cells. This usable form is called ATP a. ATP: Adenosine triphosphate 3. Organisms use E and get rid of wastes The chemical reactions that take place are called Cellular Respiration def: basic life process that releases E stored in food occurs in ALL living organisms, including plants - respiration breaks down larger molecules (ex. Glucose) into smaller molecules - releases E in the process - occurs in the mitochondria of cells of the organisms Photosynthesis and Cellular Respiration are opposite reactions - photosynthesis takes in small molecules and solar E: to produce large compounds - cellular respiration uses the large compunds to release useable E and small molecules as waste ATP CR--6CO2(g)+6H2O(l)leaves6O2(g)+C6H12O6(s) mitochondria sunlight + chlorophyll Types of Systems: System: objects, orgs, processes or things that have some relationships or influence on one another 3 types: 1. Open systems: a. A system that exchanges energy and matter with its surroundings eg. Human Body 2. Closed System a. A system which exchanges energy with its surroundings, but not matter Eg. Greenhouse 3. Isolated System: a. A system in which matter and energy are NOT exchanged with the surroundings - rare, have to b done in labs -eg. Perfectly insulated closed thermos Exchange of matter and energy are controlled by the Law of Conservation of Mass, and the Laws of Thermodynamics

Planet Earth is a closed system - takes in energy from the Sun - no matter exchanged between Earth and space surrounding it on Earth PS and CR are in balance they create an enviro on Earth and are sustained by this enviro (with the addition of solar E) Gaia Hypothesis: Lovelock 1960’s Earth is a single, connected living system that is continually responding and reaction to changes: -life on Earth and the enviro interact - this interaction allows for life to exist and be sustained

Chapter 3: Weather Energy for the Weather Energy from Sun converted in thermal E -warms lithosphere, hhydrosphere and lower atmosphere - causes water to evaporate and air to move - results in weather. Weather: Short term changes in temperature, precipitation, winds, humidity, clouds, storms and air pressure Climate: Long-term general weather trends in certain geographical area. Needs at least a decades weather data to describe an areas climate. Factors determining climate and weather systems: -Location The sun heats unevenly A) air near North and South Pole are cooler, near equator is warmer Latitude: determines the intensity and duration of Solar E B) the higher the altitude, the cooler the air C) air near large bodies of water is more humid, has more precipitation, and has a more moderate temp. - Uneven Earth Heating

A) Earth is round- amount of Solar E stricking it varies, solar radiation strikes at different angles Angle of Incidence: Angle between the ray falling on the surface and the line of the perpendicular to that surface B) different heat capacities between regions Insolation: amount of solar E received by a region of the Earth’s surface surface reflection of Solar E Eg. Snow reflects more Albedo: % of solar radiation that is reflected that is reflected by a surface C) Atmosphere Global Convection Currents- atmosphere trapping inferred radiation= heat -Global Convection Currents A) warm air at equator rises, cooler air from near poles comes down -convection currents cause mixing of cool polar and warm equatorial air masses - moderates global temperature extremes and creates mvmt. around the globe - Rotation of the Earth Coriolis Effect -causes air to move from West to East -forms jet streams -Coriolis effect bends or deflects moving air currents in response to the rotation of the Earth - creates Earth’s prevailing winds Doldrums, trade winds, westerlies, polar easterlies - Warm or Cold Ocean Currents -distribute thermal E more evenly in North/South direction -climate near warm ocean currents usually more moderate and warmer due to the heat from the water

Water- A KEY TO LIFE ON EARTH! The Unique Properties of Water (7) 1. Water has a high surface tension water molecules are attracted to each other, this is called COHESION water molecules are also attracted to molecules of other substances, this is called ADHESION

2.

3.

4.

5.

6.

7.

SURFACE TENSION is a result of cohesion and adhesion at the same time water has a very high surface tension Liquid water has a very large specific heat capacity SHC- the amount of heat it Joules it takes to raise the temp. of a specific mass of a substance by one degree Celsius - the SHC of liquid water is much larger than the specific heat capacity of many other substances. SHC can be calculated using c=Q/m*deltaT c= SHC Q=heat energy T=temp Q=mc delta T Water can exist in more than one state at a time water is constantly changing phases. Each phase change involves an exchange of energy with the surrounding the fact that all 3 phases of water exist in the hydrosphere at the same time has a great influence on life forms and on the atmosphere What has a relatively high melting and boiling points when a substance changes from one phase to another, we call it a phase change, always with energy during a phase change the temperature remains constant as heat enters liquid water at 100oC, it converts liquid water to water vapour. The temperature remains contants Water has a very high heat of fusion is the amount of heat needed to cause the phase change from solid to liquid, or heat lost from liquid to solid very high: Hfus=6.01KJ/mol to calculate: Hfus=Q/n n=mols Water has a very high heat of vaporization amount of hear needed to cause change from liquid to vapour, heat released from vapour to liquid Hvap=40.65KJ/mol to calculate: Hvap=Q/n The density of ice is less then the density of liquid water this allows ice to float on water due to this fact, bottoms of lakes do not freeze in the winter, because the ice has formed on the top and does not expose the lower water to the cold