ELECTRICITY

-All matter is made of atoms
-In the nucleus are positively charge protons and neutral neutrons
-Surrounding are negatively charged electrons
-Usually, no. electrons = no. protons
-More protons than electrons = positively charged
-More electrons than protons = negatively charged
-Equal pos and neg charge = neutral or uncharged

Static Electricity:

-charge = addition or removal of ELECTRONS (unlike protons, they are not held together and so can be easily moved)
Static electricity is due to the buildup of charge in some objects by:
1. Friction: neutral to neutral: Rub plastic with wool--> electrons move from wool to plastic --> wool is positively charged having lost electrons, plastic is negatively charged having gained electrons
2. Contact: charged to neutral: neutral substance gains or loses electrons
-Static electricity can leak slowly through substances such as rubber or air

3 LAWS:
-Unlike charges ATTRACT
-Like charges REPEL
-Charged objects ATTRACT uncharged objects*
Note: The larger the charge difference, the stronger the attraction/repulsion
*eg. Neg rod near neutral paper, pos from paper is attracted to surface closest to the rod, if strong enough, paper may be pulled to rod due to attraction
Other examples:
-wiping surfaces with a cloth leaves electric charge which attracts light, neutral dust particles
-TV and computer screens also attract dust when in use
-Walk on a carpet, friction gives electric charge
-Small electric shock when charges move very quickly to/from your body
-Moving car shares electric charge with passengers, shock as charge moves to the ground via body
-Lightning occurs when movement of particles within a cloud causes the top to be positively charged and bottom to be negatively charged, when the neg builds up it moves to ground or other clouds as a spark of lightning

-An electric field is the area around a charged object

THE ELECTROSCOPE:
-Positive charges DO NOT move
Situation 1: Neg rod, neg repelled down, leaf diverges because negatives are now all at the bottom and like charges repel
Situation 2: Pos rod, neg attracted to the top, leaf diverges because only pos is left at the bottom and like charges repel
Situation 3: Pos rod, neg attracted to top, pos rod touches, neg jumps onto the rod, rod taken away, leaf diverges because only pos is left on the electroscope and like charges repel
Situation 4: After situation 3, finger touches electroscope, pos attracts neg from your finger, electrons jump to electroscope, leaf goes back to original state (this is earthing)

Circuits and Currents:

-For a globe to light up, the circuit must be complete
-A closed switch will complete the circuit
-An open switch will make the circuit incomplete
-A complete electrical circuit is a continuous pathway where electricity can flow
-Power supply: provides electrical energy, battery or power point
-Load: electrical energy is changed into other forms of energy, globe
-Conducting path: allows electrical energy to flow around the circuit, wires
-Current: measure of how much electrical charge passes through a point in the circuit in one second or rate of flow of charge, amperes or amps or A
-Voltage (aka potential difference): energy carried by the charge or amount of energy contained in electrons flowing in an electric circuit, unit is volt



SERIES OR PARALLEL:
-Series: all components are connected in a single path so there is only one path for electrons to flow
-the more light bulbs, the dimmer all the lights will be (with 3 in a series, each gets one third of total voltage)
-if one goes out, they will all go out
-it doesn’t matter which globe goes out
-Parallel: there is more than one continuous path for the electrons to flow
-with more light bulbs, the brightness is still the same as having just one (each globe uses the full voltage of the battery)
-if one goes out, others are unaffected
-it (obviously) does not matter which one goes out

USING A MULTIMETER:
To measure current (in amperes, A) we use the multimeter as an ammeter connected in series
To measure voltage (in volts, V) we use the multimeter as a voltmeter connected in parallel
-Below, the ammeter would replace one globe in series circuit 2, the voltmeter would replace one globe in the parallel circuit



CONDUCTORS AND INSULATORS
The size of the electric current depends on resistance.
-little resistance = large current
-materials with little resistance = conductors = most metals
-materials with a lot of resistance = insulators = many nonmetals such as air, rubber
-filaments, in heating elements, have some resistance causing charge to release energy in the form of heat as it tries to get through
Note: Current is measured in A (amperes) or mA (milliamperes). 1000mA=1A

BATTERIES
-a battery is made of two or more cells, although it more often refers to a single cells (eg the things we put in torches)
-A cell has two electrodes and a substance for electric charge to flow through (electrolyte)
-when two electrodes are joined by a conducting path, a chemical reaction releases charge and allows current to flow
-dry cells are filled with a paste of chemicals
General purpose dry cell:
-electrodes are a central carbon rod on pos terminal and zinc case touching the neg terminal
-reaction between zinc and paste = charge allowing current to flow
-separating layer stop reaction while battery is not in use

-Alkaline cells allow greater electric current to flow
-ideal for heavy-duty torches, digital cameras

-Mercury cells have a steadier voltage than dry cells
-ideal for hearing aids, watches, calculators

LEMON/GRAPEFRUIT BATTERY
-Lemon/grapefruit with 2 metals, wires and an LED
-We know it works because the LED lights up
-The more fruit connected in series, the higher the electric current
-The electrode = the two metals
-Electrolyte = acid in the lemon/grapefruit juice

-Lead dioxide car batteries and nickel-cadmium mobile phone batteries are rechargeable
-A battery charger can be used to reverse the reaction that causes electric current to flow

:D

Nevermind, i found the fish. But still please feed.

:'(

I think a fish died. There were 7. Please feed

Geography Quiz

Climate Change Revision:

Greenhouse effect is entirely natural:
-Greenhouse gases, esp. water vapour, form part of Earth’s atmosphere
-Gases allow sun’s energy to enter atmosphere
-Energy radiated back, some trapped, some radiates into space

Enhanced greenhouse effect, result of human activities:
1. Solar heat, incoming solar radiation passes through atmosphere, warming land and sea
2. Heat trap, with more co2, more heat is trapped
-CFC’s, cause thinning of ozone layer
-Deforestation, produces co2
-Fossil fuels, releases large amounts of carbon
-Nitrous Oxide, from nitrogen-based fertilizers and fuel
-Vehicles, exhaust is source of heat-trapping gases
-Methane, from people and animals
-Oceans, unable to absorb as much co2 as is produced, increased temperature reduces this ability

Enhanced greenhouse effect
-->increased average global temperature and sea surface temperature
-->sea levels rise, changed ocean circulation, changed atmospheric circulation
-->Leads to climate change
-->Affects coastal areas, weather, agriculture, human health, ecosystems/habitat

Factors causing climate change:
-The increase of fossil fuels; coal, oil and natural gases contain carbon which is released when burnt. 20billion tonnes of co2 produced annually, 10billion reach the atmosphere, the rest absorbed by plants and oceans
-Deforestation; Clearing, burning and decay of vegetation release co2 that is stored in trees into the atmosphere. Also, reduction in vegetation means there are fewer plants to absorb/store co2
-Increase in methane production; Agricultural production where herbivorous animals such as cattle and sheep release methane, as well as rice paddies and other forms of irrigated agriculture. Land fill, forest fires and extraction of coal or gas also contribute.
-Increase in nitrous oxides; fossil fuel burning, motor vehicles and nitrogen-based fertilizers in agriculture are all responsible.
-Chlorofluorocarbons; once used in devices such as fridges, aircon, plastic foam and aerosol cans, they have been phased out since 1989 but once released, last for up to 100 years in the atmosphere.
-Increase in water vapour; indirectly, atmosphere warms through increase of other gases, and so temperature rises, evaporation increased and thus water vapour levels increase

INCREASE IN HUMAN POPULATION, NEED TO FEED PEOPLE, INCREASING MODERNISATION OF SOCIETY

Global warming: increased will be distributed unevenly across the world, differences between land and sea temperatures, changes in physical process affecting climate
Thermohaline circulation: Aka the great conveyer belt, it is the movement of ocean water powered by differences in salinity and temperatures. Air in the atmosphere is constantly moving as different parts of the globe receive different amounts of heat from the sun.

Global warming alters ocean circulation and heating, thus air above also moves differently resulting in shifts of the existing climatic belt
Sea level rise:
1. When water warms it expands, causing sea level rise
2. Warmer temperatures melt polar ice caps and mountain glaciers, adding to sea level

Impacts on weather:
Weather is driven by heat from the sun, causing circulation in the atmosphere and hydrologic cycle. Additional heat speeds up the system, increasing movement of air and water
1. Rainfall; Atmosphere is able to hold more water vapour, thus some places will be drier and others will be wetter. In general, dry places will become drier, wet places wetter. Flooding, landslides, and drought will increase.
2. Storms; tropical cyclones need warm water to form, thus temperature increase will increase distribution and intensity of these storms.
3. Heat waves; more extreme temperatures occurring due to climate change, affecting people crops, livestock, fish and wildlife. Wildfire risks also increase.

Impacts on coastal areas:
-islands submerged, increased flooding damage to crops and buildings meaning food production is decreased and money spent on protection, fresh water contaminated by saltwater

Impact on ecosystems and habitats:
-species forced to migrate, others that cannot adapt will become extinct, some habitats such as coral reefs destroyed by warmer conditions, water temperatures rise killing organisms and affecting food chains and ecosystems, migrating/distant species incur flow-on impacts

Impacts on agriculture:
-some plants unable to grow in increased temperatures, weeds, insects and plant diseases will expand, soil moisture changes may increase/decrease which kill plants that are unable to adapt, and increased co2 should increase photosynthesis and stimulate plant growth

Impacts on human health:
-freshwater shortage due to contamination, increasing drought, water quality affected so diseases such as cholera spread, range of diseases carried by vectors increase, more extreme natural disasters cause death more air contaminants from expanding deserts affect those with respiratory conditions.

Combating global warming:
-global policies such as Montreal protocol of 1987 and Kyoto Protocol of 1997 reducing emissions
-carbon taxes, energy-efficient technology, incentives for business to reduce, education, public awareness, renewable energy, reforestation, incentives to individuals, setting targets
-have energy-efficient homes, plant trees, reduce consumption (plastics, cans), use public transport locally grown food, bikes and walking car that suits needs, encourage government

EATING TO LIVE

EATING TO LIVE

Atoms (may not be in test, but it’s in my notes):
All substances are made of particles called atoms
Elements: composed of one type of atom
Compound: when 2 or more different elements are chemically bonded
Molecule: separate units of 2 or more molecules (eg. Water molecules)
Mixture: 2 or more elements are found together but not chemically bonded

We eat for:

-energy
-health
-nutrients: vitamins, minerals, fats, fibre/roughage, protein, carbs, water
-life
-growth and recovery
-to function properly
-warmth
-fun
All living organisms require energy; in animals cellular respiration supplies this
Oxygen + glucose = carbon dioxide + water + energy

Digestion:



a: salivary glands – Makes saliva containing enzymes which break down starch
b: liver – makes bile which breaks down fats, controls blood sugar, destroys poisons and stores vitamin A, D and iron
c: gall bladder – bile is stored here, which breaks down fats into small droplets so that lipases can access them
d: bile duct – tube that carries bile from gall bladder to duodenum
e: duodenum – site of digestion for carbs, fats and proteins, short part of small intestine connecting to stomach
f: appendix: kind of useless, may help fight some diseases
g: anus: faeces passes through
h: rectum: final part of large intestine, faeces storage
i: large intestine: absorbs water, vitamins and minerals from undigested material which passes through
j: small intestine: digestion of fats carbs and proteins; foods and liquids are broken down into nutrients which are absorbed into bloodstream
k: pancreas – makes alkaline pancreatic juice to neutralise stomach acids and enzymes
l: stomach – hydrochloric acid and muscle movement mixes food with gastric juice to break down protein.
m: diaphragm*
n: oesophagus – carries food from mouth to stomach using peristalsis (involuntary muscle contractions)
o: trachea*
p: mouth - food and saliva mixed, teeth for mechanical digestion
q: nasal passage*
r: pyloric sphincter – band of muscle that regulates movement of food out of the stomach
caecum: in plant-eating mammals it breaks down cellulose which is found in plant cell walls
ileum: last section of small intestine, absorbs nutrients
*m, o, and q are probably not needed

Process of digestion:

-food enters the mouth where it is chewed with teeth and mixed with saliva to break down starch
-travels down the oesophagus to the stomach
-stomach churns food, hydrochloric acid kills germs and allows enzymes to work
-food travels to the first part of the small intestine, the duodenum. Food mixes with bile from the gall bladder and pancreatic juices with enzymes from the pancreas. Carbs fats and proteins are digested. Minerals are absorbed
-food goes through small intestine; nutrients absorbed into bloodstream
-indigestible food continues to large intestine; water, vitamins and minerals are absorbed. Faeces is formed
-Faeces stored in rectum
-Passes through anus

Mechanical and Chemical digestion:

Mechanical: physically breaks down food into smaller pieces. (chewing with your teeth, stomach churning)
-3 types of teeth; incisors for biting and cutting, canines for tearing and grasping, molars/premolars for grinding and crushing
Chemical: where chemicals in your body react with the food which change the substances in food into simpler chemicals that can be absorbed into you blood (amylase in saliva, protease, lipase)


Enzymes:

-Assist chemical digestion by increasing rate of reactions
-The smaller an object is, the higher its volume to surface area ration becomes
-In digestion, this means smaller food particles are more exposed to digestive chemicals and enzymes
-Made of protein
-If enzymes become overheated they become denatured so they can’t work
-Substance being broken down is the substrate
-Resulting substance is the product
-Are specific for jobs they do
-Amylases: break down carbs (eg starch) into glucose
Produced by pancreas and small intestine
-Lipases: break down fats/oils into fatty acids and glycerol
Salivary glands, pancreas, small intestine
-Proteases (such as pepsin): break down protein into amino acids
Stomach, pancreas and small intestine
-Hydrochloric acid: kill bacteria and help produce acidic conditions for enzymes to work
Produced in stomach

Carbohydrates:

-rice, pasta, bread, cereal, oats, potato
-energy source
-extra energy stored as starch in plants, glycogen in animals
-cellulose in plant walls=fibre/roughage to maintain cholesterol and glucose levels and keeps food moving along the digestive system
-building blocks are glucose
-in fruit = fructose
-in milk = lactose
-normal sugar = sucrose
-starch, occurs in plant cells as grains. Each grain is surrounded by a membrane which comes apart when cooked

Proteins:

-meat, poultry, fish, eggs, dairy, nuts, lentils, beans soy, wheat
-molecules are enzymes, antibodies (defending the body), structural such as keratin and hormones
-major function – growth and repair
-made of chains of amino acids
-some amino acids must be eaten, others produced by the body

Fats:

-butter, lard, dripping, oil, margarine, nuts, fried food
-Animal fats become liquid when heated, plant fats usually liquid at room temperature
-energy
-in mammals, stored under skin for warmth and organ protection
-building blocks are fatty acids and glycerol
-saturated fats: maximum amount of hydrogen possible, they increase cholesterol and risk of heart disease. Animal fats are saturated.
-polyunsaturated fats: contain considerably less hydrogen than maximum amount. Plant oils contain high proportion of polyunsaturated fats which reduce cholesterol.


Nutrient tests:

Reagent Nutrient
Sugar Diastix
Starch Iodine
Protein Sodium hydroxide + copper sulphate
Fat Brown paper
Water None, this was used as a control for comparison

Some definitions:

Ulcer: a break in the mucus lining of the stomach
Quantitative: Deals with numbers and measurable information such as lengths, weights, ages time
Qualitative: Deals with descriptions and can be observed but not measured, such as colours, tastes or opinions
Emulsify: separate (mechanical digestion); bile emulsifies lipids like fats so that it has a larger surface area
Denatured: cannot go back to original state so cannot function
Carnivores: eat meat
Herbivores: eat plant material (will have a larger caecum)
Omnivores: eat plants and meat (may have larger caecum)
Insectivores: feed on insects
Insulin: turns excess glucose to glycogen for storage

I will update tomorrow night, tell me if i missed anything, you've probably been in more lessons than I have :)

Hello,

Just a hint; the fish will not die if you overfeed them (glares at certain people, hint hint)

ihearthorses

Hi Everyone,

What a fantastic test week people seem to have this week! :)

More importantly, THESE REVISION SHEETS ARE NO LONGER FREE.

You MUST feed the fish on the right to use them, or they will eat you (the fish, not the revision sheets)

Nah, jks, but please do feed them

From
ihearthorses