Sunday, January 11, 2009

Thursday, January 8, 2009

Journey to a Black Hole


It seems a lot of you are very curious about the stars, galaxy and the mysterious black hole, especially when I discussed about the speed of light. Here's an excellent interactive site that you can 'play' with to explore not one but two black holes!


Wednesday, January 7, 2009

$30 = $29?!?!?!



Three men dine in a restaurant. The total bill is $30 and each man hands the waiter $10. Later, the cashier realises that there has been a mistake and the actual bill is $25. The waiter returns the change of $5. Since it's hard to distribute $5 among the three people, the three men decided to give the waiter a $2 tip and each men got back $1 change.

This means that each man has paid $9, making it a total of $27. Including the $2 tip, the 3 men has paid in total $29. But didn't they pay $30 in the first place? Where has that $1 gone to?!?!


Try and explain this. The first correct answer to reach my email will get a small prize!

Update 08 Jan 2009 9:22pm: Thanks for all your participation! After 1 day, one of my Sec 2 student has emailed me with a correct and reasonable explanation. To see her answer, select the blank space below with your mouse cursor.

Well, in the first place if 3 men paid $9, it becomes $27. FROM THE
$27, $2 already has been paid as a tip! Why do we have to then add $2 yet
again!. For example, from the $30 we remove $25, leaving us with $5. that $5 had
$2 as a tip. so we add $2 to $25, isn't that $27? and $27 divided by 3 is $9!
Each man paid $9! So, basically, you all have confused yourselves, by adding
another $2 to $27 when it already has been there, and the remaining $3 was the
change given to them:)

Friday, September 12, 2008

3D drawing software - Google Sketchup


Found this rather interesting (and free) software: Google Sketchup. Interesting because it enables you to draw in 3 dimension as well as manipulate it around to give you views from different angle.


Perfect for those who have trouble visualising 3D trigonometry problems.

Thursday, September 4, 2008

Test your English

Take the test at http://www.helloquizzy.com/tests/the-commonly-confused-words-test.

Here's my result:

Your result for The Commonly Confused Words Test...

Advanced

You scored 93% Beginner, 100% Intermediate, 100% Advanced, and 73%
Expert!

You have an extremely good understanding of beginner, intermediate, and
advanced level commonly confused English words, getting at least 75% of each of
these three levels' questions correct. This is an exceptional score.
Remember, these are commonly confused English words, which means most
people don't use them properly. You got an extremely respectable score.

Thank you so much for taking my test. I hope you enjoyed it!

For the complete Answer Key, visit my blog:
http://shortredhead78.blogspot.com/.

Take The Commonly Confused Words Test at HelloQuizzy

Wednesday, September 3, 2008

A 'simple' maths problem

A teddy bear has a cost price of $18, and a selling price of $21. One day, a young man decided to buy that bear and gave the shopkeeper a $100 dollar bill.

Unfortunately, the shopkeeper do not have $100 change. Hence he went to change the $100 bill into smaller change from a passer-by and gave the change to the young man.

After some time, the passer-by realise the $100 is a fake and demanded his money back from the shopkeeper! The shopkeeper has no choice but to return $100 to the passer-by.

Question: how much exactly did the shopkeeper lost?

Friday, August 29, 2008

Friday, July 11, 2008

Make your own balance toy

I have came across an interesting wooden balance toy, usually found in the markets of Vietnam and Thailand. Unfortunately, I lost mine and this is the only similiar picture I can find online:

However, you could make your own balance toy by simply using a piece of cardboard!



Step 1 - Download the picture (click on it and download the full size).






Step 2 - Print the shape on a piece of carboard and cut out the shape.

Step 3 - Bend at the lines to create this:


There you have it! Now watch as it does a seemingly impossible act by balancing on the tip of a pen.




Questions to ponder:






  1. Is the toy considered stable?


  2. Where do you think is the CG of the toy?


  3. Do you think the toy is able to balance if you do not let the 'wings' droop down?


Ans: (highlight the space below with your cursor)





  1. Yes, because the toy returns to its original position after being tilted.


  2. The C.G. is below the tip (pivot), along the line of gravity pull.


  3. No. This is because moving the wings upwards will cause the C.G. to move upwards, resulting in an unstable equilibrium. I.e. the moments created by the weight of the toy when the C.G. is above the pivot will tend to topple it. When the C.G. is below the pivot, the moments created by the weight will tend to move the toy back to the original position.

Wednesday, July 2, 2008

My posting

I realise I haven't update that I've been posted to Kranji Secondary school. You can find out more from their website: http://www.kranjisec.moe.edu.sg/ A beginning teacher is a very busy person...



Sorry Shuqunites, I did request to go back but I guess Shuqun do not lack Physics teacher. Still, all the best for your 'O's! If you need help just let me know.

Wednesday, June 4, 2008

English Pronunciation

Though I do not teach English and neither is my command of the language strong, just wanna post this here to share. Try it!

Source: http://bertc.com/english.htm


English Pronunciation!?!
If you can pronounce correctly every word in this poem, you will be speaking English better than 90% of the native English speakers in the world. After trying the verses, a Frenchman said he'd prefer six months of hard labour to reading six lines aloud. Try them yourself.


Dearest creature in creation,

Study English pronunciation.
I will teach you in my verse
Sounds like corpse, corps, horse, and worse.
I will keep you, Suzy, busy,
Make your head with heat grow dizzy.
Tear in eye, your dress will tear.
So shall I! Oh hear my prayer.
Just compare heart, beard, and heard,
Dies and diet, lord and word,
Sword and sward, retain and Britain.
(Mind the latter, how it's written.)
Now I surely will not plague you
With such words as plaque and ague.
But be careful how you speak:
Say break and steak, but bleak and streak;
Cloven, oven, how and low,
Script, receipt, show, poem, and toe.
Hear me say, devoid of trickery,
Daughter, laughter, and Terpsichore,
Typhoid, measles, topsails, aisles,
Exiles, similes, and reviles;
Scholar, vicar, and cigar,
Solar, mica, war and far;
One, anemone, Balmoral,
Kitchen, lichen, laundry, laurel;
Gertrude, German, wind and mind,
Scene, Melpomene, mankind.
Billet does not rhyme with ballet,
Bouquet, wallet, mallet, chalet.
Blood and flood are not like food,
Nor is mould like should and would.
Viscous, viscount, load and broad,
Toward, to forward, to reward.
And your pronunciation's OK
When you correctly say croquet,
Rounded, wounded, grieve and sieve,
Friend and fiend, alive and live.
Ivy, privy, famous; clamour
And enamour rhyme with hammer.
River, rival, tomb, bomb, comb,
Doll and roll and some and home.
Stranger does not rhyme with anger,
Neither does devour with clangour.
Souls but foul, haunt but aunt,
Font, front, wont, want, grand, and grant,
Shoes, goes, does. Now first say finger,
And then singer, ginger, linger,
Real, zeal, mauve, gauze, gouge and gauge,
Marriage, foliage, mirage, and age.
Query does not rhyme with very,
Nor does fury sound like bury.
Dost, lost, post and doth, cloth, loth.
Job, nob, bosom, transom, oath.
Though the differences seem little,
We say actual but victual.
Refer does not rhyme with deafer.
Foeffer does, and zephyr, heifer.
Mint, pint, senate and sedate;
Dull, bull, and George ate late.
Scenic, Arabic, Pacific,
Science, conscience, scientific.
Liberty, library, heave and heaven,
Rachel, ache, moustache, eleven.
We say hallowed, but allowed,
People, leopard, towed, but vowed.
Mark the differences, moreover,
Between mover, cover, clover;
Leeches, breeches, wise, precise,
Chalice, but police and lice;
Camel, constable, unstable,
Principle, disciple, label.
Petal, panel, and canal,
Wait, surprise, plait, promise, pal.
Worm and storm, chaise, chaos, chair,
Senator, spectator, mayor.
Tour, but our and succour, four.
Gas, alas, and Arkansas.
Sea, idea, Korea, area,
Psalm, Maria, but malaria.
Youth, south, southern, cleanse and clean.
Doctrine, turpentine, marine.
Compare alien with Italian,
Dandelion and battalion.
Sally with ally, yea, ye,
Eye, I, ay, aye, whey, and key.
Say aver, but ever, fever,
Neither, leisure, skein, deceiver.
Heron, granary, canary.
Crevice and device and aerie.
Face, but preface, not efface.
Phlegm, phlegmatic, ass, glass, bass.
Large, but target, gin, give, verging,
Ought, out, joust and scour, scourging.
Ear, but earn and wear and tear
Do not rhyme with here but ere.
Seven is right, but so is even,
Hyphen, roughen, nephew Stephen,
Monkey, donkey, Turk and jerk,
Ask, grasp, wasp, and cork and work.
Pronunciation (think of Psyche!)
Is a paling stout and spikey?
Won't it make you lose your wits,
Writing groats and saying grits?
It's a dark abyss or tunnel:
Strewn with stones, stowed, solace, gunwale,
Islington and Isle of Wight,
Housewife, verdict and indict.
Finally, which rhymes with enough,
Though, through, plough, or dough, or cough?
Hiccough has the sound of cup.
My advice is to give up!!!

Thursday, April 10, 2008

Error in TYS notes



Thanks to Leslie for this. Can you spot the error?