Thursday 28 February 2013

Why don't Birds on a wire get a shock?

By Rama Kumaraswamy Thoopal; Illustration by Shinod AP

Now how is that possible? The fact is, for a living creature to get a �shock� there has to be a substantial flow of current through the body. However, there is barely any current running through the bird�s body for two reasons. Firstly, the bird not only forms a circuit with the wire, but it also offers a high resistance to current, so the current passes through the wire instead of the bird.

Why don't Birds on a wire get a shock?, 5W&H for kids: 192_1.gif It�s a bit like this, would you prefer going on a smooth road or a road full of potholes? The answer is obvious and just like you, the current prefers taking the easier path. All objects offer some amount of resistance to the flow of current, depending on the material.

This is just one of the reasons why birds don�t get shock, however the more important reason why current does not pass through the bird is, there is barely any, if at all, voltage difference across the bird. Current flow is actually just the flow of minute charged particles that are invisible to the naked eye. These charged particles need an energy input in order for them to get transferred. The amount of energy needed to move the charges from one point to another is measured in terms of the potential difference between the two points.

A bird perched on high-tension wires has both its feet placed firmly on the same wire, so the net potential difference from one end of the bird to the other is, for all purposes, next to nil.

In order for current to flow through the bird, there must be a sizeable difference in voltage across the body. While the potential difference between the wire and Earth may be thousands of volts, the potential difference between the bird's two feet is extremely tiny and so a very small current flows through the bird which can barely be registered.

If the bird were to touch the wire and simultaneously another wire, it would receive a mild shock. On the other hand if it were to touch the wire and some other object connected to the ground, it would receive a deadly shock, the greater the potential difference, the greater is the current flow.

Adjectives - 2

English Idioms & Idiomatic Expressions beginning with "J"

Jack Frost
If everything has frozen in winter, then Jack Frost has visited.
Jack the Lad
A confident and not very serious young man who behaves as he wants to without thinking about other people is a Jack the Lad.
Jack-of-all-trades
A jack-of-all-trades is someone that can do many different jobs.
Jam on your face
If you say that someone has jam on their face, they appear to be caught, embarrassed or found guilty.
Jam tomorrow
(UK) This idiom is used when people promise good things for the future that will never come.
Jane Doe
Jane Doe is a name given to an unidentified female who may be party to legal proceedings, or to an unidentified person in hospital, or dead. John Doe is the male equivalent.
Jekyll and Hyde
Someone who has a Jekyll and Hyde personality has a pleasant and a very unpleasant side to the character.
Jersey justice
(UK) Jersey justice is very severe justice.
Jet set
Very wealthy people who travel around the world to attend parties or functions are the jet set.
Jet-black
To emphasise just how black something is, such as someone's hair, we can call it jet-black.
Job's comforter
Someone who says they want to comfort, but actually discomforts people is a Job's comforter. (Job's is pronounced 'jobes', not 'jobs')
Jobs for the boys
Where people give jobs, contracts, etc, to their friends and associates, these are jobs for the boys.
Jockey for position
If a number of people want the same opportunity and are struggling to emerge as the most likely candidate, they are jockeying for position.
Jog my memory
If you jog someone's memory, you say words that will help someone trying to remember a thought, event, word, phrase, experience, etc.
John Doe
John Doe is a name given to an unidentified male who may be party to legal proceedings, or to an unidentified person in hospital, or dead. Jane Doe is the female equivalent.
John Hancock
(USA) John Hancock means a signature- his signature on the engrossed copy of the Declaration of Independence is very prominent.
John Q Public
(USA) John Q Public is the typical, average person.
Johnny on the spot
A person who is always available; ready, willing, and able to do what needs to be done.('Johnny-on-the-spot' is also used.)
Johnny-come-lately
A Johnny-come-lately is someone who has recently joined something or arrived somewhere, especially when they want to make changes that are not welcome.
Join the club
Said when someone has expressed a desire or opinion, meaning "That viewpoint is not unique to you". It can suggest that the speaker should stop complaining since many others are in the same position. Example: "If this train doesn't come, I'll be late for work!"  "Join the club!"
Joined at the hip
If people are joined at the hip, they are very closely connected and think the same way.
Judge, jury and executioner
If someone is said to be the judge, jury, and executioner, it means they are in charge of every decision made, and they have the power to be rid of whomever they choose.
Juggle frogs
If you are juggling frogs, you are trying to do something very difficult.
Jump down someone's throat
If you jump down someone's throat, you criticise or chastise them severely.
Jump on the bandwagon
If people jump on the bandwagon, they get involved in something that has recently become very popular.
Jump ship
If you leave a company or institution for another because it is doing badly, you are jumping ship.
Jump the broom
To jump the broom is to marry. (Jump over the broom, jump over the broomstick, jump the broomstick are also used.)
Jump the gun
If you jump the gun, you start doing something before the appropriate time.
Jump the shark
Said of a salient point in a television show or other activity at which the popularity thereof begins to wane: The Flintstones jumped the shark when a man from outer space came to visit them. The expression derives from an episode of the television sitcom 'Happy Days' in which Fonzie, clad in leather jacket and on water skis, jumps over a shark. That episode was widely seen as the beginning of the end for the formerly popular series.
Jump the track
Jumping the track is suddenly changing from one plan, activity, idea, etc, to another.
Jump through hoops
If you are prepared to jump through hoops for someone, you are prepared to make great efforts and sacrifices for them.
Jump to a conclusion
If someone jumps to a conclusion, they evaluate or judge something without a sufficient examination of the facts.
Jumping Judas!
An expression of surprise or shock.
Jungle out there
If someone says that it is a jungle out there, they mean that the situation is dangerous and there are no rules.
Jury's out
If the jury's out on an issue, then there is no general agreement or consensus on it.
Just around the corner
If something is just around the corner, then it is expected to happen very soon.
Just as the twig is bent, the tree’s inclined
Things, especially education, that affect and influence us in our childhood shape the kind of adult we turn out to be.  (There are various versions of this, like 'As the twig is bent, the tree's inclined' and 'As the twig is bent, so the tree inclines', 'As the twig is  bent so is the tree inclined')    
Just coming up to
If the time is just coming up to nine o'clock, it means that it will be nine o'clock in a very few seconds. You'll hear them say it on the radio in the morning.
Just deserts
If a bad or evil person gets their just deserts, they get the punishment or suffer the misfortune that it is felt they deserve.
Just for the heck of it
When someone does something just for the heck of it, they do it without a good reason.
Just for the record
If something is said to be just for the record, the person is saying it so that people know but does not necessarily agree with or support it.
Just in the nick of time
If you do something in the nick of time, you just manage to do it just in time, with seconds to spare.
Just off the boat
If someone is just off the boat, they are naive and inexperienced.
Just what the doctor ordered
If something's just what the doctor ordered, it is precisely what is needed.
Justice is blind
Justice is blind means that justice is impartial and objective.

Wednesday 27 February 2013

COMPUTER



Find the words below in the grid.
Words can go horizontally, vertically and diagonally, backwards or forwards.
SCREENCTCGXN
ZZDDTRVFLYYS
TNORCEPASTEO
NWWAEDVMWPMF
KZNONGMARZDT
KXLBNFHOSRNW
YMOYOKGPUFZA
RJAECROTOSJR
OKDKATZLYYEE
MFKMPTDGPPLV
EFMAJEGOPTER
MELKRMCRELIF
© 2005 - www.learn-english-today.com  - software 1-2-3 Word Search Maker™

 
   connect    keyboard    programme
   copy    laptop    save
   download    memory    screen
   file    mouse    software
   folder    paste    type

Padi - Sahabat Selamanya (Lagu Tema Upin & Ipin)

Friday 15 February 2013

CAT WORD SCRAMBLES

Unscramble the first four words in each set of scrambles. Then use the circled letters to unscramble the final word. Some of the words may unscramble into more than one word, but only one word is related to the puzzle.

1. HOUSE CATS

E I K T N T

E L E P S Y

C E H R S T T

A I L T

Answer:

2. HOUSE CATS 2

E M W O S

A K L S S T

A L I T

E H N R T U

Answer:

3. WILD CATS

A C E E H H T

A D E L O P R

I L N O

E G I R T

Answer:

4. CAT BREEDS

A E I N P R S

A M X N

A B E L S

A C M O T T

Answer:







Answers: 1. kitten,sleepy,stretch,tail,kitty litter 2. meows,stalks,tail,hunter,whiskers 3. cheetah,leopard,lion,tiger,panther 4. persian,manx,sable,tomcat,siamese