Chemical Bonding Is Just As Complex As Human Bonding.

It's been a while since I last posted because my mocks finished and I didn't think I'd have any more revision to do. But then I got my Science results, and with the exception of Physics (which I did the most revision for), I was really disappointed. So I need to work on bringing Biology and Chemistry up to scratch.

This is a chemistry post, concentrating on the different ways atoms bond, and there might be a little bit later on Carbon Nanotubes. This post isn't going to be like before with the endless facts and figures. It's going to a be a bit more talkative, more readable and relate-able.

So, there are two different types of atom bonding that I need to know for the exam. One is Ionic and the other is Covalent. I can remember the differences by remembering the ionic bonding causes ions to be made, and covalent bonding means two together, like COhabitation means two people living together.

Okay, so ionic bonding. In ionic bonding, the atoms want to gain a full outer shell. Atoms on the left side of the periodic table only have one or two electrons, so they'll want to get rid of them, for example. When these atoms lose or gain electrons, they're called ions. These ions are then attracted to other atoms/ions with opposite charges to their own.

EG - Sodium (Na) and Chlorine (Cl)

Now I need to talk about the properties of these ionic bonds, but there's a lot to remember, so I'm going to try and liken it with stuff I understand.

These ionic bonds are strong and produce huge ionic structures, like a friendship is strong and produces lots of memories. Also like a friendship, ionic bonds don't melt easily because they're so tough. This means they have high melting and boiling points. But, when the ions do roam free, such as when dissolved in water or molten, they can conduct electricity (kinda like when a friendship breaks and rumours and secrets start being spread).

Example of ionic bonds are salt (which is in the shape of a cuboid, like all ionic structures), and dissolved lithium in batteries.

Okay, now on to covalent bonds. Covalent bonds occur when two atoms decide to share electrons, kind of like a cheating boyfriend (for lack of better example). Sharing a boyfriend causes both girls to feel that they have a loyal boyfriend, and in covalent bonds, the atoms feel they have a full outer shell.

For every covalent bond (or cheating boyfriend), there's one extra electron for each atom (or one extra problem for each girl).

Examples of covalent bonds are -

Hydrogen (H2)...

And Ammonia (NH3) ...

That's all I have to know on bonding, so here is some info on carbon nanotubes.

A carbon nanotube is like rolled up graphite.

- It conducts electricity

- It's 10 000 times smaller than a human hair.

- Crystals can be grown inside it.

- They may replace wires in the future.

My next post will probably be on the reactivity series :)

John Galliano, You Are My Idol.

Woo an interesting post at last.

This one's on Textiles :)

Okay, so my mock is tomorrow, and I have to learn the following things -

• Analysing products (good and bad features, usability, quality of fabric and why the fabric was chosen)
• The importance of design spec
• Batch (10-1000) and mass (1000+) production
• Recycling (6 R's and labels)
• Info on John Galliano
• Evaluation (on going and summing-up)
• Testing products
• Mood boards and inspiration
• Primary and secondary research

How to rack up the points on design -

• Brush up on graphical skills (proportion, shape, dimension, multiple views, line quality and colour-way)
• Construction processes and design features
• Ergonomic features
• Innovation
• Fabrics

Seams - open, french, double stitched, overlocked

Shaping - darts (single/double point), tucks, gathers, elasticated, drawings, castings

Fastenings - zips (open/closed), velcro, straps, buckles, buttons, buttonholes

Finishing to edges - hems, facings, piping, binding (show magnification)

Sleeves - cap, short, elbow, 3/4 length, bracelet, long, raglan, set in, gathered,

Collars - eton, shirt, peter pan, tailored, round neck

Pockets - tab, welt, box pleat, gathered

Fabrics - stretch jersey/polyester/cotton, textured breathable polyester, proofed cotton, brushed cotton

I'm actually about to kill myself coz I'm so bored.

Have to go read the text book, so I might post again laterssss :)

This Blog Is An Electrical Device.

This post was supposed to be entirely on electricity, but I missed out a bit on car safety last time, so here it is -

Stopping distance = thinking distance + braking distance

Internal factors that effect thinking -

• pets
• kids
• phones
• smoking
• eating
• drinking
• radio
• beautifying
• reading

External factors that effect thinking -

• idiots in other cars
• hot models
• illness
• drugs
• alcohol
• caffine
• physical inabilities
• animals

Other factors - AGE

Factors that effect breaking distance -

• quality of brakes
• tires (width and grip)
• road surface (stoney/smooth)
• grass / mud / sand
• ice / snow / surface water / wind / other weather factors)

Okay, and now on to electricity -

Current - is the flow of electrons around a circuit

Voltage - is the push driving the electrons

Resistance - is something slowing down the current

Ammeter - is something that measures the current (Amps/A, resistance = voltage/current)

Electrons flow the opposite way to a conventional current because they're negatively charged and flow from negative to positive.

The current in a series circuit is the same at every point, whilst the current in a parallel circuit is divided up.

If a bulb is added to a circuit, both bulbs will get dimmer (providing they're the same watt).

Ammeters are always connected to a circuit in series, whilst a voltmeter is connected in parallel.

Resistance can be calculated using Ohm's law -

Resistance (Ohms) = Voltage (V) / Current (I)

Resistance is also shown using current-voltage graphs

Think wires have more resistance than think ones. If you halve the cross section of a wire, the resistance doubles because there's half as much space for the electrons to move.

Different materials also have different resistance, for example, a nichrome wire has more resistance than a copper one of the same size because the atoms in nichrome hold the electrons tighter then copper.

LDR - is a light dependant resistor. The more light that falls on it, the less resistance there is.

Thermistor - is temperature sensitive. As the temperature increases, the resistance decreases.

PLUGS!

There's my plug diagram ^

When wiring a plug, you must -

• not have extra wire poking out of the pin block
• screw it down fully
• make sure no excess wire will be pinched when the lid is put down
• make sure the cable grip has a tight grip on the cable

Earth wires - are always used in appliances with a metal case. If a fault develops and the live wire touches the metal case, a surge in the current does down the earth wire, causing the fuse to blow. This makes the appliance insulated.

Live wires - alternate between high positive and high negative voltage and an average of about 250V.

Neutral wires - are always at 0V.

Fuses - are designed for safety. If a fault develops, a large current flows through the the fuse and causes it to melt. This breaks the circuit and protects the appliance and user.

Power = Voltage x Current

(W = V x I)

MCB - is a a miniature circuit breaker, aka a resettable fuse that you can turn back on after a power surge.

RCD - is a radical current device, which looks at what goes in and out of an appliance and can detect when an appliance is using too much current.

WHOOOOP.

That's all the work I've done on Physics, which is lucky because I have my exam tomorrow.

Big Up The Jamaican Accent.

This post is Biology. I dislike it very much coz I have a mock on it tomorrow and a real GCSE in January. But hey, revision's gotta be done.

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Enzymessss! -

• proteins
• biological scissors
• used to cultivate insulin
• have an optimun temperature of 37C (and denature when the temp rises too high)
• a higher concentration = a higher rate of reaction
• has to be the correct shape to fit its substrate

Diffusion - the movement from an area of high concentration to low concentration (down a concentration gradient)

Concentration - the larger the difference between the concentration of molecules, the faster it will diffuse

Temperature - the higher the temp, the faster it will diffuse

Pressure - the higher the pressure, the faster it will diffuse

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Cell membrane - is selectively permeable

OSMOSIS (and Jamaican accent) - the diffusion of water molecules from an area of high to low concentration

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Aerobic respiration --

Glucose + Oxygen > Carbon Dioxide + Water (+ Energy)

Anaerobic respiration -

Glucose > Carbon Dioxide + Ethanol (+ Energy)

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The digestive system - is a long muscular tube in which enzymes speed up (catalyse) the breakdown of large insoluble molecules (eg. fats, proteins, starch) into smaller soluble molecules so that they can pass through the wall of the small intestine and into the bloodstream.

Amylase - breaks down starch (into glucose)

Protease - breaks down proteins (into amino acids)

Lipase - breaks down fats and glycerol

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Photosynthesis -

Carbon Dioxide + Water > Glucose + Oxygen

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Food chainsss -

Producers - plants that make their own food using light energy

Herbivores - animals that only eat plants

Carnivores - animals that only eat other animals

Omnivores - animals that eat plants AND other animals

Predator - an animal that hunts other animals

Prey - an animal that is hunted by other animals

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The Carbon Cycleee

Carbon enters the atmosphere from - combustion in factories, respiration in plants, photosynthesis in plants and the decay of animals.

Carbon enters the earth from - the decay of dead animals and plants (eg. sedimentation).

Cardon enters animals from - consumption.

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Harming the Earth --

Eutrophication - fertilisers in water, which leads to growth of plankton and stops light entering water sources, which kills water animals

Biodiversity - a wide range of different species living in one habitat

Hole in Ozone layer - unstable ozone is being harmed by water vapour, CFC (spray cans) and emissions

Greenhouse effect - earth warming due to increasing Carbon Dioxide in atmosphere

Bioaccumulation - chemicals being passed along food chain (think leaf, worm and robin)

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Intensive food production -

Advantages in Agriculture -

• genetically uniform
• reliable
• large quantities
• no land waste
• predicted yield
• resistance to disease
• predicted need for fertiliser

Disadvantages in Agriculture -

• unnatural ecosystem
• easy to wipe out with disease
• no control over unwanted pests
• eutrophication

Advantages in Husbandry -

• large production
• no land waste
• efficient
• cheap food

Disadvantages in Husbandry -

• animals have bad life
• disease
• suffering (crippled chickens)
• bad food quality
• bioaccumilation

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Bovine Tuberculosis (bTB)

bTB - is a very serious disease among cattle in Britain

Can be controlled by - vaccination, testing badgers, checking cattle when sold, controlling cattle movement more and culling infected herds

Whoop. That's Biology sorted, only Chemistry to worry about now :)

This Brain Works Faster Than The Speed Of Light.

Physics again, so here are a couple of formulas I need to learn for Speed, Distance and Acceleration -

speed = distance travelled / time taken

acceleration = change in speed / time taken to change speed

(acceleration = (final speed - start speed) / time taken

If distance is measured in metres(m) and the time in seconds(s) then speed is measured in metres per second (m/s)

Acceleration (or deceleration) is caused by an unbalanced force, such as legs on a bike.

Velocity - is almost the same thing as speed, except is is a vector quantity. Velocity has a direction as well as a size. Eg - if a car is travelling at a constant speed in a straight line, then it has a constant velocity. But if it turns a corner, its velocity changes even though the speed remains constant. Similarly, a car travelling in the opposite direction has a negative velocity.

Terminal Velocity - is the fastest an object can move when all forces are working upon it (Eg. when a person jumps out of a plane, and then again when they fully open their parachute).

Kinetic Energy ---

KE = 0.5 x M x V

(J = 0.5 x Kg x (m/s)^2)

Any object that moves has kinetic energy.

Forces!!

Resultant force = Mass x Acceleration

Weight = mass x force of gravity (neutons, N)

Mass = how much of something there is (Kg)

1Kg - 10N

Work = force x distance

When a force moves an object, energy is transferred and work is done.

Change in potential energy = mass x gravitationl field strength x change in height

Or

Change in potential energy = weight x change in height

Hallelujah!! So glad that's over, but might have to post again laters :)

Gonna Give Einstein A Run For His Money In My Physics Exam. Not.

This could be a long post, so I'm just gonna get on with it.

Radioactivity --

Alpha (a) -

• two neutrons, two protons (helium)
• big, heavy, slow moving
• don't penetrate very well (stops at paper and skin)
• strongly ionising
• bent by electric and magnetic fields
• used in smoke alarms (because it's not dangerous to humans on the outside)

Beta (B) -

• one electron
• quite fast and small
• penetrate moderately before colliding and ionising moderately
• stops at aluminium
• bent strongly by magnetic and a electric fields
• used for thickness control (paper and rollers)

Gamma (y) -

• a wave
• penetrates a long way
• stopped by lead
• weakly ionising (passes through instead of collides)
• used for power generation
• used for checking welds
• used to sterilise stuff in hospitals

Problems with radioactivity -

• can cause cancer
• can cause mutations
• can be used for terrorism
• no where safe to store waste radioactivity

Half life

• radioactivity decreases over time, but never reaches zero. Half life is the time it takes for half of the atoms to decay.
• eg - 1000 atoms > 100 atoms... 1000/2 = 500... 500/2 = 250... 250/2 = 62.5... 4 x 2 = 8 hours / 4 half lives

Background radiation -

• is naturally all around us (but is no danger to our health)
• comes from the air, our food, building materials, rocks under our feet, space (cosmic rays) and human activity (nuclear explosions and waste)
• proportions are - 51% radon and thoron gas, 14% rocks, 12% medical x-rays, 12% food, 10% cosmic rays, 1% nuclear industry
• measured in Becquerel (Bq)
• 1 Bq = one nucleus decay per second

That's everything I have on radiation. It's a hell of a lot, and I still have Distance, Speed, Acceleration, Velocity, Forces, Car Safety and Electricity to get through. By Thursday.

Argh, wish me luck.

Obama In The White House. Take That, KKK.

No, I'm not being racist. This is History revision.

The Slave Trade - Britons sold goods in Africa and were given rival blacks in return. Blacks were sold in America, in return for goods which went to the UK.

Jim Crow Laws - segregated people. Had separate facilities. Black salaries, transport and supplies were inferior, high schools for blacks were rare, people weren't paid until the harvest came in, overcrowded homes, couldn't vote, had to pay to vote or pass a reading test (blacks could do neither).

The Harlem Renaissance - some talented black musicians in the North achieved success, such as Billy Holiday and Louis Armstrong. But, they could rarely perform for blacks.

The KKK - Set up in 1865 and wanted to continue white supremacy. Lynched everyone, tarred and feathers, raped girls and castrated boys.

The NAACP (National Association for the Advancement of Coloured People - wanted to improve the quality of life for blacks by defending blacks in court, published a magazine called Crisis and campaigned to get the vote for blacks.

The Depression - hit blacks hard, very little help for them until the second phase of the New Deal was introduced, which involved Alphabet Agencies and allowed blacks to work in local or state offices.

WWII As A Turning Point - Intelligent blacks joined the Tuskegee Airmen and had a taste for life in Europe where they were treated as equals. Returned to their own countries and were still treated badly, so wanted to make a change. Government couldn't fight against racism when it was happening in its own country.

That's all I've covered on race issues in the USA, so I'm hoping that's all I'll need for the exam :)

I might post later with some nerdy sciencey stuff, not sure yet though!

Yn Fy Marn I, Cymraeg Yn Dwp.

I have my Welsh Reading and Writing Exam tomorrow. I'm not sure what I can type here, so I'm gonna put some basic word sentences and hope I remember the rest :)

Hoffwn i - I would like (no n/yn)

Hoffwn i fod yn - I would like to be

Yn y byd - In the world of

ddisgybl - pupil

ddiddorol - interesting

profiad gwaith - work experience

teimlo'n - feeling

baswn - I would

gallwn - I could

lle - where

megis - such as

felly - so

hefyd - also

delio gyda chwsmeriad - dealing with customers

berffaith i mi - perfect for me

arholiad(au) - exam(s)

ysmygu - smoking

yfed - drinking

cyffuriau - drugs

gormod - too much

mae'n achosi cancr - it causes cancer

gaeth - addicted

rhai pobl - some people

cymryd (cyffuriau) - take (drugs)

penwythnos diwethaf - last weekend

A dyma pedwar paragraffau defnyddiol -

Gwaith rhan amser - Yn fy marn i, rydw i'n meddwl bod gwaith rhan amser ym Ffantasteg. Mae fy frindiau yn gweithiau yn y siop gyda ei mam. Mae hi'n hoffi gwaith yn y siop, felly rydw i eisiau swydd hefyd. Hoffwn i weithio yn y byd arian yn y dyfodol, felly rydw i'n edrych am swydd mewn swyddfa neu gyda cyfrifydd.

Partion - Rydw i'n caru partion! Mae fy frindiay yn hoffi gwisg ffansi a dawnsio. Yn fy marn i, mae partion yn hwyl, ond mae rhaid pobl yn dwp. Nhw weithiau cymrydd cyffuriau ac yfed gormod o alcohol. Yn fy marn i, mae yfed tipyn bach o alcohol yn iawn, ond mae gormod o alcohol ddim yn dda.

Chwaraeon - Rydw i'm meddwl bod chwaraeon yn iawn achos mae'n hwyl. Rydw i'n caru chwarae pel-rwyd ac dwly ar gwylio bechgen chwarae rygbi! Mae fy mrawd yn mwynhau chwarae pel-droed ac yn mae'n chwarae am Gaerdydd. Ond, dydw i ddim yn cytuno gyda fy mrawd achos rydw i'n teimlo'n wedi blino ar ol chwaraeon.

Ffasiwn - Rydw i'n cary ffasiwn! Mae llawer o 'Vogue' gyda fi ac rydw i eisiau bag Chanel achos fy hoff dylunydd ydy Karl Lagerfield. Ond, dydy Jodi ddim yn cytuno achos mae hi'n caru Louis Vuitton.

Whooop.

That took longer than expected, but I'm proud of my revision tonight.

English Literature and Welsh Listening was fine today, and I also have RS tomorrow, which was be fineeeee :)