My very own simple motor

Although I had learn this in my Secondary school days, this is the first time I tried it. I think it works pretty well :)



Materials:

• coil of insulated wire
• paper clips for support
• magnet
• batteries and wires
• a base to mount everything

Note: you need to strip HALF the insulation at the ends of the wire.

For more info, go to http://www.youtube.com/watch?v=it_Z7NdKgmY

Old but good video - Frames of Reference

May be too complex for some of you but do give them a try and wonder as you sit there and watch the video: are you stationary or are you actually moving at quite a fast speed?

Physics video by UMass Lowell

A great video which I guess is shown to freshman in this university. Credits to Win? Fail? PHYSICS!

Introducing: Prezi - the zooming presenter, presenting simple Electricity

Tired of Powerpoint slides? Frustrated by the limitation of Powerpoint or MSOffice in creating large concept maps?

Introducing Prezi, a different way to present. It surely is interesting for both the presentor and the audience, as the zooming and panning effects just capture your attention much more than the Powerpoint usual fade in-out sequence. What's more, it is a great tool to present concept maps.

Created one based on Electricity. It's still kinda rough around the edges and lacking in content....cos it's not as 'user-friendly' as Powerpoint. Comments welcomed!

Electricity - Introduction and Current Electricity on Prezi

The invisible rod

Two similiar acrylic rods are placed in two different liquid. The one of the right is water, the one on the left is corn syrup. Why couldn't the submerged portion of the rod be seen in the jar on the left?

Game for Physics - 99 Bricks

How often does a teacher encourages you to play games? But here I am, recommending this brilliant online flash game called 99 Bricks.

It's essentially Tetris with a twist: the aim is to build the TALLEST structure! However, the bricks observe the laws of stability, momentum, balance of moments, forces due to weight and centre of gravity etc etc....

Link: http://www.kongregate.com/games/WeirdBeardGames/99-bricks

Spending time on youtube

Despite my busy schedule, I've been spending some time on Youtube. Partly because I'm finding interesting clips to share with my students, partly to find some inspiration for the contestants of the Amazing Science X Challenge (http://www.asxc.com.sg/).

Anyway, here's one that I really like. It's by Steve Spangler, on a popular talkshow by Ellen Degeneres.

Watch the first one here! Go check out his other videos too.!

Brain Teaser

You have 12 pearls. 11 of them are real, and 1 of them is fake. They all look/feel/everything EXACTLY the same, the only difference between the real and fake ones is their density.

You are given a balance scale (one of those old school scales that compare weights. You can weigh/compare the pearls three (3) times. Describe how you would:

1) determine the fake pearl

2) determine whether the fake pearl is more or less dense than the real pearls.

Post your answer in the comments!

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.

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!

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:

Materials
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


Dimensions
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)

Pre-Competition

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

Results
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.... :)

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.


By mrguay

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

Trust me ;)

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:

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!

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:

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.

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

Objective
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!

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

Requirements:

• 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! :)

Java Applet to show Principle of Conservation of Energy

Quite a no. of students are interested in getting this applet, hence I'm posting the link here:

http://phet.colorado.edu/simulations/sims.php?sim=Energy_Skate_Park

It's totally free. Try it!

Total Internal Reflection

A rather good video from Harvard, showing a professor explaining total internal reflection. Enjoy!

Singapore Paper Plane Challenge

Free on 15th March? Have plenty of unwanted A4-size paper?

Contribute to a Singapore World Record! Fold as many Nakamura Lock paper airplane and head down to Singapore Science Centre on 15th March 2009. For more information, go to the official website: http://www.science.edu.sg/ssc/ibrowse.jsp?artid=8572&type=19&root=0&parent=0&cat=470

Watch a video on how to fold this paper airplane.

Video - Moments and an application in daily life

Don't mind the dirty fingers. Enjoy.