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Transcript of Chemistry
Cell Wall- Only plant cells, bacteria, fungi, and some algae have a cell wall. The cell wall is a rigid frame around the cell that provides strength, protection, and support.
Smooth endoplasmic reticulum- Smooth endoplasmic reticulum is associated with the production of fats and oils. Smooth endoplasmic reticulum does not have an ribosomes.
Ribosomes- Ribosomes are small, dense looking organelles that may be attatched to the rough endoplasmic retuculum or free in the cytoplasm. Ribosomes are the sites where proteins are assembled.
Nucleolus- In the nuclei,(control centre of the organelle) It also contains a small denser area which is called the Nucleolus.
Cell Membrane- The cell membrane forms a protective barrier around the cell. The cell membrane is made up of a double layer of lipids (a fat molecule that doesn't dissolve in water) The cell membrane is designed to allow different substances to move through it. Moving substances across the cell is called diffusion.
Cytoplasm- All cells contain cytoplasm. It is a jelly like substance that fills the cell and surrounds the organelles. Cytoplasm contains the nutrients required by the cell to carry on its life process.
Nucleus- The nucleus is the control centre organelle of the cell. It controls all the activities in a cell, including growth and reproduction.
Vacuoles and Vesicles- Vacuoles and Vesicles are membrane bound organelles what store nutrients, waste and other substances used by the cell. in plant cells, the central vacuole stores water for the cell.
Mitochondria- All cells require a source of energy; the organelles known as mitochondria supply the energy. Mitochondria are the power house of the cell. Reactions occur in these organelles to convert the chemical energy in sugar energy the cell can use.
Lysosomes- Lysosomes are organelles where digestion takes place. They are small organelles that are filled with enzymes. An enzyme is a protein that can speed up cbemical reactions in the cell. Lysosomes also break down reactions in the cell. Lysosomes aso break down invading bacteria and damaged cell organelles. They work as a clean system in the cell.
Golgi Apparatus- The golgi apparatus recieves proteins. From the endoplasmic reticulum, The function of the Golgi apparatus is to modify, sort and package these proteins for delivery throughout the cell or outside the cell.
Rough endoplasmic retticulum- The endoplasmic reticulum is an organelle that is made of a series of interconnected small fubes that carry materials through the cell. Rough endoplasmic retticulum is associated with making proteins.
Different Organelles in Plant and Animal Cells
Important Cellular Mechanisms
Formula for Magnification
Every cell has a cell membrane- this membrane forms a protective barrier around the ell and is designed to carry out a very important cellular mechanism- the process of allowing different substances to move through the cell membrane to enter, or exit the cell!
One such process for moving substances across the cell membrane is called diffusion. Diffusion depends on the concentration of the substance on both sides of the cell membrane.
Concentration is the amount of dissoved particles of a substance, called solutes, in a solution is the concentration.
When a substance is present in different concentrations on either side of the cell membrane, the particles will diffuse, or move, from an area of high concentration to an area of low concentration.
Magnification can be found by multiplying the objective lens with the ocular lens.
Given- magnification of objecive lens 100x
Given- magnification of ocular lens 10x
Analysis and Solution- Multiply the magnification of the objective lens with the ocular lens to get total magnification
(100x)(10x) = 1000x
Paraphrase- Therefore, the total magnification is 1000x
The Cell Cycle Terms
Cell Cycle- Through careful observation, scientists have identified a repeating cycle of events in the life of a cell. This cycle of events is called the cell cycle. During much of the cell cycle, the cell grows and prepares for cell division.
Interphase- The cell is in interphase when it is preparing for cell divison.
Mitosis- Cell division involves packaging the genetic information in the nucleus into two equal portions; this process is called the mitosis. Cells use mitosis in the process of growth and repair.
Chromosomes- Evert cell contains chromosomes. Each chromosome is a long piece of coiled DNA and proteins. The number of chromosomes in each cell differs between chromosomes. e.g Horses have 64 chromosomes, hermit crabs have 254 and humans have 46; 23 matching
Sister Chromatids- Before cell division can occur, each chromosome is copied. The chromosome consists of two identical copies, called sister chromatids. When the cells divide, one chromatid goes to each of the new cells.
First Growth Phase (G1)- This phase is a period of growth for the cell. During this phase, the cell also produces new proteins and organelles. If the cell is healthy and conditions are favourable, the cell moves to the next phase.
Synthesis Phase (S)- During this phase, the cell makes (synthesizes) an entire copy of the DNA of the cell. Key proteins that are associated with chromosomes are also produced during this phase.
Second Growth Phase (G2)- Once the DNA has been copies, the cell moves into second growth phase. During this phase, the cell produces the organelles and structures needed for cell division. This phase is the shortest of the phases of interphase.
Cytokinesis- During the last phase known as the telophase, the cell divides the cytoplasm into two portions. The process of splitting the cytoplasm is known as cytokinesis. For animal cells, the cell membrane pinches inward, eventually splitting one cell into two cells. For plant cells, the cell plate forms the cell wall and inner plasma membrane in each of the new cels. At the end, they go back into interphase conditions. The cycle is then repeated.
Apoptosis- A cell also dies as a normal part of the functioning of healthy multicelluar organisms. They regulated, or controlled cell death is called Apoptosis. Apoptosis is the death of cells that are no longer useful.
Phases of Mitosis
Cell Division and Cancer
Cell division is essential for all life, and cell divison is essential for cell growth and cell repair and replacement, and cells of multicellular organisms all undergo cell growth and ell division at different, yet "controlled rates".
However, when a cells divide "uncontrolably" they are called cancer cells.
- Cancer cells develop when a change occurs in the cell that affects how the cell divides.
- When a cell's DNA is changed, it is known as mutation.
- Some viruses and evironmental agents, such as ultraviolet radiation, or cigarette smoke, can cause cell mutations.
- Some cancer causing mutations are inherited.
- normal cells usually life for about 50 to 60 cell divisions, while cancer cells can seem to be immortal.
- A normal cell will undergo apoptosis if it is damaged genetically, whereas cancer cell will continue to divide.
Comparing Normal Cells with Cancer Cells
- Make exact copies of themselves through mitosis
- Reproduce for about 50-60 cell divisions
-Stick together to form masses of cells as appropriate
-Self destruct when too old or too damaged
- Make exact copies of themselves through mitosis
- Do not stop reproducing
- Do not stick to other cells
- Behave independently
- May move to another location of the body
Specialization and Stem Cells
Every cell in your body originally came from a small group of stem cells. A stem cell is initially an unspecialized cell. However, these stem cells are capable of becoming any cell- including nerve cells, blood cells, or muscle cells- in the human body.
There are two types of animal stem cells: Embryonic stem cells, and Adult stem cells
Embryonic Stem Cells:
-Found in almost all parts of embryos
-Can undergo differentiation and become any kind of tissue or organ
Adult Stem Cells:
- Adult stem cells are found in only certain locations in adults
-Adult stem cells can become only a certain kind of tissue or organ
-Most adult stem cells are involved in the replacement of damaged tissue. For example, adult stem cells are found i skin, bood, and neutral tissue.
Meristematic Stem Cells
Plant stem cells are called meristematic cells.
- They are found in the growing tips of roots and stems.
- Also found i a layer of the stem knows as the cambium.
- Are active throughout the life of the plant- they continually produce new cells of various types.
-lines body cavities and outer surface of body
-forms glands that produce hormones and enzymes
-supports and protects structres
-fills empty space
-allows for movement
-responds to stimuli
-transmits and stores information
-unspecialized tissue capable of dividing by mitosis
-found in several locations in the plant
-forms the protective outer covering
-allows the exchange of materials and gases into and out of the plant
-in the stem: provides strength and support
-in the roots: stores food and water
-in the leaves: where photosynthesis occurs
-moves substances from the roots to the leaves
-transports sugars from the leaves to other parts of the plant
Main Animal Organs
Skin- The skin protects the inner cells from damage, acts as a defense against disease organisms, insulates, releases heat and excretes bodily wastes.
Lung- Your lungs allow you to breathe in oxygen and breathe out carbon dioxide.
Heart- The heart is a muscular pump that supplies blood to all parts of the body.
Organs of Digestion
Mouth- Your mouth takes in food and begins digestion. The mouth is lined with epithelial tissue.
Esophagus- Once the food enters your body, it travels from the mouth down a tube called the esophagus. The food moves along the esophagus because of the rhythmic constriction and relaxation of the smooth muscles that line the esophagus.
Stomach- Further down the canal, food enters the stomach, which is made of epithelial, connective, nervous and muscle tissues. The stomach churns good and makes it with dijestive juices and enzymes.
Liver- The liver is the second largest organ, the skin is larger and heavier the liver performs many essential functions to digestion, metabolism, immunity and the storage of nutrients in the body.
Pancreas- The pancreas is located in the abdomen. It plays an essential role in converting the food we eat into fuel for the body's cells.
Intestines- The digested nutrients and undigested waste products move into the small and large intestines which are areas of chemical digestion and removal of wastes.
Rectum and anus- Solid wastes are stored in the rectum and exit the body through the anus.
Main Animal Organ Systems
Mouth, esophagus, stomach, pancreas, gallbladder, liver, intestines, rectum
nose, mouth, trachea, lungs, bronchi, bronchioles, alveoli, diaphragm
Heart, blood vessels, blood
Brain, nerves, and spinal cord
-absorption of nutrients
-elimination of solid wastes
-exchange of gases
-transpiration of materials (such as oxygen, nutrients, hormones, and wastes) within body
-controls body functions
-coordinates responses and activities
Medical Imaging Technologies
How does it work? The X ray is high energy radiation that can easily penetrate materials such as skin and tissues but cannot penetrate metals and bone. A radiograph is produced when x rays pass through the body to produce an image. Since x rays are absorbed by dense structures such as bone, the bones appear whiter than other structures. Radiography are used to check for cancer and to diagnose problems in the cardiovascular and respiratory sustain. A mammogram uses x rays to check breast tissue for the presence of cancer.
The x ray is the most common form of medical imaging. It cannot easily penetrate metals and bone. Radiologists view the radiograph either as a photographic film or on a computer screen. A radiologist is a doctor who has been trained to diagnose diseases or problems by recognizing abnormalities in the radiograph. Radiographs are also used by dentists to check for cavities in your teeth. Using X-rays are usually quick and painless, however, if the x ray is at a high energy radiation, it could cause mutations in your DNA. Therefore, when undergoing an x-ray, a lead apron may be used because x rays can not penetrate certain thickness of lead. A chest radiograph are for finding abnormalities in the lungs and show the size of the heart and blood vessels.
X- Ray Fluoroscopy
How does it work? Fluoroscopy is a new technique that uses a continuous beam of x rays to produce images that how movement of organs, such as the stomach, intestines, and colon, in the body. Fluoroscopy is also used to study the blood vessels of the heart and brain.
The patient may be required to ingest a contrast liquid, such as barium or iodine, to help the doctors the organ clearly. The image of the blood vessels is called an angiogram. In a coronary angiogram, a specialized dye is injected into an artery in the groin. This dye enables doctors to visualize the blood flow. The angiogram shows any narrowing of the arteries. A cerebral angiogram shows any blockages in the blood vessels.
X- Ray Radiotherapy
In addition to using c rays to see structures in the body, x rays are also used to treat cancer. This type of therapy is known as radiotherapy. the x rays damage the DNA and either kill the cancer cells or prevent them from multiplying. during radiotherapy, a beam of x rays is directed at a tumor so that there is minimal damage to healthy normal cells.
Radiotherapy may be combined with other forms of cancer therapy, including surgery and chemotherapy
How does it work? Ultrasound images uses high frequency sound waves to produce images of body tissues and organs. Ultrasound is used to study soft tissue and major organs i the body. ultrasound is also used in the diagnosis of heart problems. an echocardiogram is used to find out if there is any abnormalities in the heart or blood vessels that could lead to problem, such as stroke.
A device called the transducer produces the sound waves. a transducer is placed on the skin. Sound waves enter the body and reflect back the reflection makes an image. Since images come out blurred by the presence of hair, or gas, the ultrasound is not recommended for imaging the intestinal area. It is not recommended for imaging bone because the waves cannot penetrate through bone ultrasound is also used when guiding a needle for when performing needle biopsy for tissue. Abnormal over 35 needs to be checked for down syndrome, cystic fibrosis ad spina bifida.
Computed Assisted Tomography
Computed tomography (CT) or sometimes known as computer assisted tomography (AT) involves using X ray equipment to form three dimensional image from a series of images at different angles of the body.
The CAT is most frequently used to diagnose cancer, abnormalities of the skeletal system, and vascular diseases. CT can be used to image bone soft tissue and blood vessels at the same time. Usually this test will be used in emergency times because it is quick,painless and detailed.
Magnetic Resonance Imaging (MRI)
MRIs are powerful magnets and radioactive to produce detailed images of the body. MRIs are useful for imaging the structure and function of the brain, heart and liver, soft tissues and the inside of bones it is also used to diagnose forms of cancer, brain diseases and cardiovascular conditions/ An MRI machine is about the size of a car and looks like a hollow cylinder. An open MRI machines open on all sides which allows a patient to be less confined when testing.
The body is made up of water, which contain hydrogen atoms. MRIs have magnets that will interact with the hydrogen atoms. The combination of radio frequencies make it possible for a specialized computer to generate an image. Open MRI permits easier testing for people who are disabled or overly anxious.
Pros and Cons of a Refracting Telescope
- simple design leads to easy usability
-good for terrestrial viewing
-great for lunar, planetary and binary star gazing
-needs very little to no maintenance
-should last a lifetime
-tend to work best in poor seeing conditions
-best quality kind out of most telescopes
-usually has small apertures
-not very practical
-good quality telescopes charge by unit of aperture so very expensive$$$
-although the image is clear, it is still possible to capture unwanted colour fringes and objects in view
-tend to lack quality for photography use
-size and weight, as aperture increases so does the weight and size
-an ok refracting telescope is already pricey
-if you're serious and you want a good refracting telescope you have to be rich
Use of Electromagnetic Spectrum
Sources of Light
Non- Luminous Objects: Objects that do not emit their own light Ex. Moon
Luminous Objects: Objects which produce the light they give off Ex. Sun, firefly
Chemical Potential Energy: A source which converts chemical energy stored within molecules into light energy. this is often called chemiluminescence. Ex. Cool lights, living organisms which use chemicals in their bodies can also produce light this is called bioluminescence and is a form of chemical energy.
Heat Energy: A source which converts heat energy within objects bruning to Produce light. this is called incandescence and produces a great deal of heat. Ex. A candle, incandescent light bulb.
Electrical energy: A source which converts electrical energy to light energy. Usually, if you pass electricity through a gas you can get light energy. Ex. Lightning, neon lights. This can also be associated with heat energy incandescence from above, fluorescence and phosphorescence.
Nuclear Potential Energy: A source which converts energy stored within the nucleus of atoms into light energy through fission and fusion. Ex, atomic bomb
Sources of Visible Light
Incandescent- Incandescent light that is produced by an object, such as metal, that is at a very high temperature
Fluorescent- Fluorescent light is light emitted by some substances when they are exposed to electromagnetic radiation.
Phosphorescent- Phosphorescence is the ability to store energy from a source for light and then emit it slowly over a long period.
Chemiluminescence- Chemiluminescence is light produced from a chemical reaction without a rise in temperature.
Triboluminescence- Producing light from friction is triboluminescence. Some crystals can be made to grow up simply by rubbing them together or crushing them.
Electric Discharge- An electric Discharge is a method for producing light in which an electric current passes through the air or another gas such as neon.
Light- Emitting Diode (LED)- The process of transforming electrical energy directly into light energy is called electroluminescence.
OLEDs- An organic light emitting display is a light source made of several extremely think layers of organic molecules that use an electric current to produce light.
Plasma displays- In a plasma display, each colour is a tiny fluorescent light in which an electrical signal causes a gas, such as neon to release ultraviolet radiation.
Liquid Crystal displays- In a liquid display, a whitelight such as a fluorescent light or light emitting diode shines behind a liquid crystal
Properties of Light
Rectilinear Propagation- This is the tendency for light to travel in straight lines especially in a homogeneous transparent medium. (unlike sound or other energy waves, light doesn't always need a medium to travel. for example, light travels in the vaccum of space, but for our purposes we will say it is traveling in something).
In general, light travels in straight lines until it strikes something. The properties of that something determines what will happen to the light. materials can be classified according to how light interacts with it.
Transparent: Transparent materials transmit light freely- light passes right through it- ex glass
Translucent: Translucent materials transmit some light, absorb and reflect some light therefore, you cannot quite see right through it.
Opaque: Opaque materials absorb and reflect all light (ex. a blackboard)
Ray model of Light: Because light generally travels inn straight lines, we often represent these in diagrams by a straight arrow and we call them rays, the arrow points in the direction the light is traveling away from its source, and the more rays, the brighter the object appears.
Because light travels in a straight line and really cannot bend around objects, a shadow is formed when an opaque object blocks the light travel. the area where light is blocked is called a shadow. the darkest part of the shadow is called an umbra, the lighter part of the shadow is called penumbra.
Light not only allows us to see objects, some optical devices (light devices- like mirrors and camera) allow us to create a likeness of the object. These are called IMAGES.
There are four main characteristics that describe images:
Size: The image can be smaller, larger or the same as the object. Magnification is the measure of how much larger or smaller an image is compared to the object itself
Orientation or Attitude: The image can be upright or inverted in comparison to the object.
Location: In front of the mirror or in the back of the mirror. This can be used to determine the TYPE of image.
Type: The type and location of an image are related. The type of image often depends on its location. A real image is the image that can be seen on a screen, in front of a mirror. It is a virtual image if the image can only be seen by looking at or through the optical device. The image is behind the mirror.
Mirrors which are simply portions of the surface of a polished sphere are used in our daily lives.for example car Side mirrors are curved mirrors. like plane mirrors, curved mirrors obey the laws of reflection. however, when parallel light rays strike a curved mirror, each ray of light will reflect at a slightly different position. All of these rays eventually meet at a common point either in front of the mirror, or virtually, behind the mirror.
Ray Diagram for Concave Diagram
drawing a concave mirror diagram:
-The first ray of a concave mirror ray diagram travels from a point on the object parallel to the principal axis. any ray that is parallel to the principle axis will reflect through the focal point on a converging mirror.
-The second ray travels from a point on the object toward the focal point. any ray that [passes through the focal point on a converging mirror will be reflected back parallel to the principal axis.
-Draw the real image where the rays intersect.
drawing a convex mirror ray diagram:
- The first ray of a convex mirror ray diagram travels from a point on the object parallel to the principal axis. any ray that is parallel to the principal axis will appear to have originated from the focal point on a diverging mirror.
-The second ray travels from a point on the object toward the focal point. any ray that is directed at the focal point on a diverging mirror will be reflected back parallel to the principal axis.
-Draw the virtual image where the rays appear to intersect.
The angles of the refracted light rays are usually measured from the normal, drawn at 90° to the surface where the light ray crosses between the two media. When light travels from air, with a low refractive index, into water, with a higher refractive index, it bends toward the normal. When light travels from a denser (higher refractive index) medium into a less optically dense (lower refractive index) medium, it bends away from the normal.
Total Internal Reflection
When a light ray traveling from a more optically dense material to a less dense material enters at a large angle, the ray bends away from the normal so much that the light does not actually escape the first medium. This means that the angle of refraction is greater than 90 degrees, and we call this phenomenon- Total internal reflection. the light is being reflected back into the dense material.
The critical angle- at a certain incident angle, called the critical angle, the refracted angle is exactly 90degrees and therefore follows a path along the surface of the media boundary. even though the light refracts, it does not leave the first medium and is trapped.
If the angle of incidence is increased beyond the critical angle, tHE angle is then totally reflected back. this is phenomenon is used in a variety of optical devices and most importantly in fibre optic devices which carry your internet signal to your house.
Converging lens- a lens that is thickest in the middle.
Diverging lens- a lens that is thickest at the ends.
Principal axis- a line passing through the center of the surface of a lens.
Axis of symmetry- an imaginary line drawn through the optical centre perpendicular to both surfaces.
Focal length- is the distance from the axis of symmetry to the principal focus measured along the principle focus.
Optical centre- the centre of the optical lens.
matter- matter is anything that has mass and takes up space (has volume).
physical property- a physical property is a property that describes the physical property appearance and composition of a substance.
chemic property- a chemical property is a property that describes the ability of a substance to change into a new substance or substances.
pure substance- a pure substance is made up of only one kind of matter and has a unique set of properties such as a colour, hardness, melting point and conductivity.
element- an element is a substance that cannot be broken down into any simpler substance by chemical means. Iron, oxygen, and neon are examples of elements.
compound- a compound is a substance that is made from two or more elements that are combined together chemically. For example, methane (CH4) is a compound containing the elements carbon and hydrogen.
mixture- a mixture is a combination of pure substances. the proportions of the pure substances in a mixture that can vary, so the properties of the mixture vary as well.
homogeneous mixture- a homogeneous mixture is a mixture that looks the same throughout and the separate components are not visible. Solutions are homogeneous mixtures.
heterogeneous mixture- a heterogeneous mixture is one in which different parts of the mixture are visible.
suspension- in a suspension, a cloudy mixture is formed in which tiny particles of one substance are held within another substance.
mechanical mixture- a mechanical mixture may contain several solids combined together, such as in a chocolate chip cookie.
atomic theory- atomic theory is the study of the nature of atoms and how atoms combine to form all types of matter.
protons- protons have a positive charge of 1+.
electrons- electrons have a negative charge of 1-.
neutrons- neutrons are neutral.
nucleus- inside an atom, protons and neutrons are in a tiny central core called the nucleus.
shells- Surrounding the nucleus and more than 10 000 times larger than it, are a series of cloud-like energy levels called shells.
bohr diagram- A bohr diagram is an illustration of an atom that shows the arrangement and number of electrons in each shell.
valence shell- the outermost shell of an atom.
valence electrons- the electrons in the valence shell of an atom.
periods- the horizontal rows of the periodic table
families/ groups- the vertical columns in the periodic table.
metals- metals are elements with the following properties: they are good conductors of heat and electricity, they are ductile and malleable, they are shiny and usually silver coloured and all but one are solids at room temperature. Mercury is liquid at room temperature.
non-metals- non metals are elements that share these properties: they are not metals, and they generally are poor conductors of heat and electricity. At room temperature, some non- metals are solids, some are gases, and one, bromine, is liquid.
metalloids- metalloids are elements with properties intermediate between the properties of non metals and metals.
alkali metals- soft, silver-grey metals that react easily with water and with oxygen in the air. Note that hydrogen is not an alkali metal.
alkaline earth metals- silver-grey metals that are harder and less reactive than group 2 metals. A reactive atom combines easily with other atoms.
halogens- coloured non-metals that are very reactive.
nobles gases -non metals that are colourless, ouderless gases and very unreactive. An unreactive atom does not combine easily with other atoms.
atomic number- the atomic number is the number of protons in an atom of an element.
atomic mass- the atomic mass of an element is a measure of the average mass of an atom of that element.
ion- an ion is an atom or group of atoms with a negative charge or a positive charge.
Type of Reaction
law of conservation of mass
The Law of Conservation of Mass states that matter can be changed from one form into another, mixtures can be separated or made, and pure substances can be decomposed, but the total amount of mass remains constant. This only applies to a closed reaction. If it is open, substances escape by evapouration etc.
Use prefixes for two non metals.
use roman numerals for elements with more than one charge
An acid is a substance that has a pH less than 7 when it is in aqueous solution. The more acidic a substance is, the lower the pH.
A base is a substance that has a pH greater than 7 when it is in aqueous solution. The more basic a substance is, the higher the pH.
Thousands of years ago in Asia and Europe, early chemists tried to classify the substances they found in nature. One property they used was taste. This property accurately distinguished acids from bases: acids taste sour, while bases taste bitter. Tasting unknown substances is not safe, and you should never taste an unknown substance to identify it or its properties.
An acid-base indicator is any substance that changes colour in the presence of an acid or a base. The most widely known acid-base indicator is litmus. Litmus is a plant extract and can be blue or red (pink). Litmus paper is made from blue or red litmus dried onto strips of filter paper. Red litmus paper turns blue when it is dipped into a basic solution. Blue litmus paper turns red when it is dipped in an acidic solution. Neither litmus paper changes colour in a neutral solution. Figure 5.6 shows a memory aid for remembering these colour changes.
A universal indicator is a mixture of chemicals that changes colour through a wide range of pH values. Paper strips called pH paper are embedded with a universal indicator. When pH paper is dipped in a solution, one or more of these indicators will change colour. You can then determine the pH of the solution by comparing the colour of the dipped strip with a standard colour chart. An even more precise way of determining pH is to use a pH meter.
Weather and Climate
Weather refers specifically to the environmental conditions that
occur at a particular place at a particular time. These include temperature,
air pressure, cloud cover, and precipitation. The morning weather
forecast may predict sunny, warm conditions, while the afternoon
forecast for the same area may call for increasing cloud cover overnight
and the possibility of precipitation.
Climate is the average weather
conditions that occur in a region over a long period of time, usually a
minimum of 30 years. The description of the climate of a region includes
average monthly temperatures and precipitation, average wind speed
and direction, and a variety of other data. Climate is studied by
climatologists, who also understand meteorology.
The climate of an area is affected by many factors. The four main
• the air masses that flow over the area
• the area’s nearness to large bodies of water
Defining and Describing our Biosphere
The atmosphere is the layer of gases that extends outward about 300 km from the surface of Earth. The major gases found in this mixture are nitrogen and oxygen. Other gases found in trace amounts are argon, carbon dioxide, neon, helium, methane, and krypton. Water vapour is also a gas found in the atmosphere, but since levels of water
vapour (humidity) can vary greatly, water vapour will be considered part of the hydrosphere in this book. Water vapour, oxygen, and carbon dioxide are essential for life.
The lithosphere is the solid portion of Earth that floats on the semifluid portion of the mantle. The lithosphere is home to many micro-organisms, plants, and animals, including humans. It is the outer surface of Earth (its crust) plus the solid part of the upper mantle. It extends downward from Earth’s surface and varies in thickness from as little as 5 km thick beneath parts of the oceans to as deep as 100 km beneath the continents. A few metres at the surface of the lithosphere
are warmed by the incoming energy from the Sun. The rest is warmed mainly by the decay of radioactive elements in the lithosphere and mantle.
The hydrosphere includes all of the water on Earth. About 97 percent of this water is salt water in Earth’s oceans. The other 3 percent is fresh water and includes liquid water, such as in groundwater, lakes, and streams, and frozen water, such as the ice in snow and glaciers.
The biosphere is the relatively thin layer of Earth that has conditions suitable for supporting life. It is composed of all the living things on Earth and the physical environment that supports them. Other planets in our solar system do not appear capable of supporting life as we know it.
Insolation is the amount of solar radiation received by a region of Earth’s surface. Insolation depends on latitude, which is the distance of any place on Earth from the equator, shown on a globe by a series of lines drawn around it parallel to the equator. The equator is at 0° latitude,
and the North Pole is at 90° latitude. Toronto is at latitude 43°40' (“minutes”) N (north of the equator). Insolation also depends on specific characteristics of the lithosphere, atmosphere, and hydrosphere
in that region.
Earth is a warm, habitable planet because Earth’s surface and the atmosphere absorb incoming insolation. However, not all the incoming solar radiation is absorbed. Some is reflected out to space, and some is re-emitted as thermal energy by Earth’s surface and atmosphere. Net radiation budget is the difference between the amount of incoming radiation and the amount of outgoing radiation.
Radiation is the emission of energy as waves. When radiant energy encounters particles of matter, it may be reflected or absorbed.
Conduction is the transfer of thermal energy through direct contact between the particles of a substance, without moving the particles to a new location.
Convection is the transfer of thermal energy through the movement of particles from one location to another.
The Coriolis effect is the deflection of any
object from a straight-line path by the rotation of Earth.
You found out that the natural greenhouse effect keeps our planet warm by absorbing some of the infrared radiation from Earth’s surface. The natural greenhouse effect is due mainly to the presence in our atmosphere of water vapour, with other naturally occurring greenhouse gases, such as carbon dioxide, methane, and nitrous oxide, also playing a role. However, these gases are also produced by human activities, such as industry, electricity generation, transportation, and agriculture
Global warming potential is a measure of the ability of a gas to trap thermal energy in the atmosphere over a specified time. Water vapour is not included in the global
warming potential classification because its concentration varies with
temperature. Climatologists have given carbon dioxide a rating of 1, and
other greenhouse gases are rated relative to carbon dioxide. The
persistence of each gas is also given. Persistence is the length of time
the gas remains in the atmosphere. Gases that persist longer can absorb
thermal energy over a longer period of time. Persistence of carbon
dioxide is not defined because it depends on the amount emitted and
carbon dioxide has a variety of sinks.
Carbon source- any process that releases carbon dioxide into the atmosphere
Carbon Sink- Any process that takes carbon dioxide from the atmosphere and stores it.
anthropogenic greenhouse effect- is
the enhancement of the natural greenhouse effect
due to human activities.