Tuesday, November 17, 2009

Combine Science (Physics) vs Pure Physics

This is a question from this year's (2009) O-Level Physics (i.e. pure physics)

And this is a similiar question in 2009's O-Level Science Physics

The difference is not in the content nor the depth of knowledge required but the answering skills and the level of understanding for both the content as well as the question.

Wednesday, October 21, 2009

Sec 2 Exp Physics - "Global Culling Blade"

Top score: 46/50.

Total 69 failures (28%)

As mentioned before, the EOY paper will be tough, and there is no other way about it because we need the results for streaming.

So students who haven't been paying much attention in class or following through the assignments timely will find the paper very hard to handle. Even conscientious students may struggle, due to the limited time (1 hr) and the very narrow margin for any error or slight doubts in your Physics concepts.

I mention this before: "If you simply study the notes we gave you and go for a Physics test, you will FAIL." There's some element of practice but mainly you need to question the theory and truly understand just what the hell this equation/law/rule is talking about.

My last piece of advice is to NOT forget all the Physics you have learnt in Sec 2, because they will be tested again in Sec 3! Regardless if you're in a Pure Physics class or a Combined Science class...

All the best! Enjoy your break...while you can!

Sunday, September 13, 2009

Bridge Challenge @ Ngee Ann 2009

Kranji Sec sent 2 teams of 8 students to take part in the Bridge Challenge 2009 organised by Ngee Ann Polytechnic. The aim was to build the strongest and lightest bridge within 6 hours, using bamboo skewers, vaguard sheet, limited string and glue.

These are the rules of the competition:

On Day 1of the competition, every team will be given the
following materials for their use:

8” Satay sticks (Pack of 180 sticks) - 5 packs
Ball string - 2 m
630 x 510 mm Vanguard sheet - 2 pcs
A4 paper - 2 pcs
4” x 5/16” Glue sticks (Pack of 12 sticks) - 1 pack

The bridge must span across two supports placed 600 mm apart (the width of each bridge support is 50 mm). The bridge may span straight from one support to the other. The width of the bridge must be at least 150 mm throughout the entire span. There is no limit to the height of bridge.

Judging Criteria
- Strength factor [Failure Load/(weight of bridge +
penalty weight)] 50%
- Design (Structural concept) 15%
- Construction (Workmanship) 15%
- Aesthetics & Innovation (Profile, shape and etc) 15%
- Fact Sheet 5%

The participants

Team 1:
  1. Yow Kai En (3B)
  2. Foo Chuan Ri (3A)
  3. Grayson Chang Fanyao (3D)
  4. Jasmend Yow (3F)

Team 2:
  1. Yap Hong Yi Desmond (3A)
  2. Ng Shao Hui (3B)
  3. Tham Chin Siong (3B)
  4. Quek Hong Wei (3A)


We started preparing only after Common Test. I foolishly thought with 3 weeks, it should be more than sufficient to prepare for the competition.

Unfortunately, I was rudely surprised at the slow pace of work the teams are producing.

Hence I went to research and build a bridge prototype (which they are suppose to do...) to give them something to base on and to benchmark against their miserable effort. Credit of the design goes to Garret Bridges (http://www.garrettsbridges.com/design/trussdesign). So I spent half a day and created this:

Team 2 decided to follow my design with some modifications. It was strong and sturdy but was also very heavy.

Team 1 will use the design based on previous bridge competition that Kranji took part in. The design was very light but the load that it can handle is questionable...

Day 1

Both teams started at 1030 am....

and ended at 430 pm. The 6 hours might sound like a long time but both teams only barely manage to finish on time.

I heaved a huge sigh of relief...

Here the some designs from other schools:

and of course the 2 bridges from Kranji!

Day 2 - Judging

The bridges are loaded at the centre as shown. Loading will stop when the bridge breaks or the maximum load of 30 kg is reached.

In addition, the participants need to explain their design concept to the judges themselves.

Some videos of the loading for our 2 bridges. The jerkiness is due to youtube...:

Team 1

Team 2

Here's a summary of the results of all the bridges at the challenge:

So how did Kranji fare?

Remember, it's not the based on the absolute load but the load factor, which is calculated by the load supported by the bridge divided by the mass of the bridge. E.g. for Team 1, their score is

Team 1 load factor: 10000 / 170 = 58.8

This score actually places them among the top 5! And they went on to win the Merit award!

Team 2 was the highlight of the competition (almost everyone wants to take a look at the Kranji bridge) because it's the only bridge that supported the maximum load of 30 kg. However, they lost in terms of load factor to Pasir Ris Crest which manage to support 16 kg with their bridge that has a mass of only 190 g.... Still, a very good job by Team 2 and they clinched the 2nd place - Silver Award!

Congratulations to all participants! Hopefully you enjoyed and more importantly learned something from this experience. I know I did.... :)

Sunday, September 6, 2009

September holiday! You're joking right?!?!

Just like Mario, there's no resting until the final level. So stop staring at your PC and go do some revision!

Source: http://wigflip.com/thankyoumario/

Monday, August 31, 2009

Teacher's Day 2009

A great big THANK YOU to all my students!

So what did I get for Teacher's Day? Well, the usual foodstuff...



So which gifts do I really prefer? Well, ask any teacher and I think you will get the same answer - we love to see you write/draw stuff to us! So thanks once again for all the cards and artwork!

Happy Teacher's Day to all of you!

Sunday, August 23, 2009

Sec 2 Exp Sci(Phy) Common Test 2 results summary

I did say it will be an easy paper, so now all of you can 'trust' my words.

The good news: most of you have done wonderfully, with half the class attaining A1s.

Image Hosted by ImageShack.us
By mrguay

The bad news: I'm setting you EOY paper, and it will be tough. Much much tougher.

Trust me ;)

Saturday, August 22, 2009

Mr Guay's Science Video Contest - Results

1st Prize goes to Edmund's (2E) video on Electrical Safety!

2nd prize goes to Daryl's (2F) video on Refraction and Rainbow!

And 3rd prize goes to Edmund (2E) again for his Lemon Battery video:

Tuesday, August 18, 2009

Play a game + revise at the same time?!?!

Play a game of "Who Wants To Be A Millionaire" and revise the topic on Current Electricity and Resistance!

Click here to play: Who Wants to be a Millionaire - Current Electricity and Resistance by mrguay

You can even create your own customised game from this website!

National Day Photos

Saturday, August 8, 2009

National Day 2009

It was nice to see most of us coming to school in red. But what struck me the most today is how enthusiastically everyone sing together when the teachers played the NDP songs.

So here are some of my favorite NDP songs in order, ending with my most favorite at the end of the post.

But I must thank http://www.sha.tc/singapore/ndp-songs for the inspiration and some of the links.

10. One People, One Nation, One Singapore (1990)
An oldie but you can't deny it's catchy and easy to sing. Lack a bit of emotion though.

9. Where I belong by Tanya Chua (2001)
Not too bad but just lack that little magic. And the tune is not that catchy.

8. Stand up for Singapore! (1985)
The first song written especially to commemorate National Day! (before that, we only have 'Chan Mali Chan' and '相信我吧! 新加坡!') Upbeat and catchy but too many politaically correct words inside. And right now, Singapore have come far enough that 'standing up' is no longer enough... the people have to do more than that!

7. Count on me Singapore (1986)
One of the songs that sometime I mistaken it for 'We are Singapore'. Soothing tune, easy lyrics, catchy chorus. But slightly corny and 'fake', yeah?

6. Home by Kit Chan (1998)
A bit melancholic (sad) and a bit slow but otherwise beautifully written. Can't say it's a song for high spirits but if you're one of those listening to this while stationed overseas, I bet tears will roll.

5. Things so Singapore by Ann Hussein (2009)
The unofficial song that had gained internet popularity in this year 2009 NDP. It's nice, but not really a 'group singing' song. I mean, you can't imagine the whole National Stadium echoing with this song, isn't it?

4. What do you see by Electrico (2009)
The first song by a Singaporean band that made it big (relatively in the local scene). The lyrics is meaningful and the tune is nice, just not perfect. It just lack that little something, a climax to the song maybe? The song begins with a question, and at the end, I'm still asking myself what do I see...

3. My Island Home by Kaira Gong (2006)
Erm...disregarding the fact that I actually know the singer in person (briefly, in NUS), I feel that this song has one of the most changes in terms of mood and tempo. Started slow and gentle, and finally crashing with a strong "I believe!" at the chorus, before settling down again.

And hearing Kaira (or Shi Jia) sing live, right in front of you without any mics or instrument, is way much better than what you hear from the CDs.

2. We are Singapore (1987-1988)

This is my most favorite NDP song before the invasion of pop singers and even poppier songs. Still, even after 23 years, you can't deny you actually prefer to sing the National Pledge rather than recite it, just like how they did it in this song.

Extremely easy to sing, lyrics are very easy to remember. Grand and yet not too sombre. Not too slow and yet not too fast like a dance music, I truly believe this is a real gem of a song. And they like it so much that this song was used for 2 years! If you haven't hear this song before, you must give it a try.

1. We will get there by Stefanie Sun (2002)
Besides that fact that I am quite a supporter of Stefanie Sun, I really like the tune of this song. The strong rhythm by the bass sets a good intro, with a gradual increase in instrument and finally peaking at the chorus. Part rock, part pop, which is what I like!

Lyrics wise I prefer the chinese version but I think the arrangement is wonderful and with Stefanie's unique voice, it's actually one of the few NDP songs that can be 'sold' as a top pick pop song.

Thursday, July 30, 2009

An old but good video on Electricity

As we embark on the new topic of Electricity, here's quite an interesting video that I found. It can be downloaded freely at http://www.archive.org/details/principles_of_electricity or from my sharing folder: http://www.4shared.com/file/121710609/7af86584/principles_of_electricity_512kb.html.

What's interesting about this video is that it's made in 1945 by a country that first entered the Nuclear Age.

For those that can't wait, you can watch it from youtube too but in 2 parts:

Thursday, June 25, 2009

Thank you 2F!

Thank you for this wonderful wedding gift!

Monday, May 25, 2009

Interclass DOTA friendly match

As requested by some of you (and I secretly wanted to do this anyway...), presenting....


Go to the forum so that I/we can plan the game schedule. Registration required for forum access, so please use a valid email address.

Update 11 Jun 2009:

Thanks for supporting the interclass games. Now back to your holiday assignment! :)

Tuesday, May 19, 2009

Mr Guay’s Science Video Contest

For the June holidays, I decided to organise a Science Video Contest! All my current students (Sec 2 - Sec 4) may apply.

To foster and cultivate the spirit of learning and self-discovery; to stimulate creativity and enhance the learning experience of Science.

Create a short video that is related to Science (preferably but not restricted to Physics).

Let your creativity flow! There’s no restriction to the format or style of video. It could be a video of you demonstrating an experiment, a magic trick, an illusion. Or it could be a collection of video clips/pictures that is related to the topic you are showing. It can even be a MTV, a comical skit or a cartoon, as long as it is related to Science!

1st: $50 voucher
2nd: $30 voucher
3rd: $10 voucher

  • Individual or group effort. Multiple entries allowed.
  • Clear explanation on the scientific principles. Explanation can be done in the video OR offline (e.g. a writeup or report).
  • Sources of information or materials used must be clearly cited
  • Allow your video to be uploaded to youtube for sharing/viewing
  • No restriction on video format, length, music used etc.
  • Judges decision is final.
  • Judging based on content (40%), creativity (30%), explanation (20%) and quality of video (10%)
  • Date of submission: 10 Jul 2009
  • Register by 29 May 2009. Registration is free!

Here are some examples from youtube:

Mr Guay’s videos:

  1. Moments: http://www.youtube.com/watch?v=2hr7LlEOv48
  2. Mirror size and distance: http://www.youtube.com/watch?v=WEV8LNn0szI
  3. Egg in a bottle: http://www.youtube.com/watch?v=_KA1d0voy74
  4. Fun with electrical fuse: http://www.youtube.com/watch?v=70arPvsHKkk

Examples from other users:

  1. Build an electric motor: http://www.youtube.com/watch?v=it_Z7NdKgmY
  2. Crushing can experiment: http://www.youtube.com/watch?v=QVayky_b-6U
  3. Floating tea bag: http://www.youtube.com/watch?v=TbkEfYohXTA
  4. Siphon: http://www.youtube.com/watch?v=O3F9hx5CjPY
  5. Boiling with ice: http://www.youtube.com/watch?v=XTJZZY1a0XE
  6. Magic balloon: http://www.youtube.com/watch?v=ucD8_y7VdvM
  7. Cartesian diver: http://www.youtube.com/watch?v=JGo7ECXCNgs
  8. Rolling back up incline: http://www.youtube.com/watch?v=D7bXHP9OmVo
  9. Static attraction: http://www.youtube.com/watch?v=WZPkCOySCWc

Sign up now! :)