Pop Can Cannon Designs

After researching various exploits of boys and what they did in their spare time back in the day, I have compiled a list of possible designs for making a pop can cannon.

Materials:

• 5 cans (minimum 3 cans for the cannon part, and 2 for support)
• Duct tape to hold them together
• Ethanol for ignition
• A pair of Styrofoam cups as ammunition
• Nail and hammer

Design Notes

• Many of the people who wrote about their experiences with making pop can cannons back in the day insist that they used tin cans, and one source even says that aluminum cans would lead to an explosion and a "face full of aluminum shrapnel". Other (probably younger) sources use soda pop cans, or steel cans such as the kind that contain vegetables or soup or juice

• Although one source uses masking tape as an option to hold the cans together, most sources say duct tape or electrical tape
• All sources use lighter fluid (butane) as the ignition, but we are using (must use) ethanol
• All the sources leave the bottom on the bottom can, through which a hole is made for getting the ethanol into the cannon. However, some sources cut all the tops and bottoms off the rest of the cans. Others say to leave in half the bottom of the first can and half the top of the third can as well. Still more involve cutting out like triangles from the third can (the one with the entire bottom and the hole) so that one end of the can looks like a star or cross

• They also all involve shaking the cannon, but I don't know whether the cannon is shaken before the ammo is put in or after... 
• launch angle
• Pictures from: http://www.spudfiles.com/forums/old-school-tin-can-cannon-t14208.html , http://t3.gstatic.com/images?q=tbn:ANd9GcRy6ueQD4GvrnM3BHSyGUUu1YiHPVX_HrpC_gaFK3oKjx-fpH8a , http://t1.gstatic.com/images?q=tbn:ANd9GcSUO-6jGB8lA0JJxmqphPDfycPlrjR6l5Q7erzkTOTZoSFlT3Isrw

Newspaper Tower

This is our newspaper tower.

My, Tannya's and Angeline's spirals :]

The materials we could use were 4 sheets of the Toronto Star and maybe a little more than a meter of tape. And we only had 30 minutes.

Ours was probably the fastest made (it took like 10 minutes), and we thought 6 feet would be tall enough...we were wrong. :( Ah well.

Why did we design our newspaper tower this way? 
We originally wanted to make a triangular prism, but decided that a design such as that of a camera tripod would be better and would conserve more newspaper: a tripod doesn't need base supports to stand up. Part of the reason why our design could stand so well no matter where it was moved was that our base was not rigidly supported, so it could adjust to different parts of the floor. Our design was very simple and required very little tape, so we used the rest for extra height (hence the 20 cm-long tape extension on the top that Mr. Chung later squished).

So whole and healthy before it got squished...also note the flag with a :D and spiral that Patrick was so proud of. 

What physics concepts did we apply?
Mainly we applied concepts that I remember learning from grade 7 science (some of the few things I retained from that class) : that triangles are the strongest of all shapes (if we built supports, they would have been triangular) because any forces applied to a point of atriangle are distributed down its sides, making it really good at withstanding pressure. Another concept that everyone applied was that the base of the tower should be bigger/wider than the top, such as that of a pyramid. Structures with bases like these are more stable because the wider base brings the center of gravity of the structure closer to the ground. This makes it less likely to fall over.

My Favourite Skyscrapers

Hmm...even though this blog is supposed to be about my favourite skyscrapers, I'm not sure I have any...I mean, it's not the same as having a favourite colour or book. Oh well. I'll do my best. 

The first skyscraper that I liked was the extremely tall Burj Khalifa in Dubai at over 828 metres tall. Incredible. It is the tallest skyscraper in the world, the tallest free-standing structure in the world (recently beating out the CN Tower), has the tallest elevator service and the longest travel distance in an elevator in the world...and many more. The entire building stands on a concrete mat multiple metres thick, and it's spiralling design "confuses" wind: as the building's shape changes, wind cannot get organized around it, so the spiral minimizes the effects of wind. 

Another one of the tallest skyscrapers that I liked was Taipei 101. It stands 509 m tall, as well as being 5 stories deep, and was built to resemble a pagoda. Taipei 101 contains an 800-ton pendulum to reduce swaying and can withstand severe earthquakes and typhoons. It is flexible enough to handle strong winds but must remain rigid enough to protect the people and structures inside it. Because Taipei 101 is so tall, it contains additional features like 380 "piles" driven straight into the ground, making it very stable. This stability was tested when it was being built in March 2002, when a 6.8 magnitude earthquake hit Taipei and the building itself was not structurally damaged. 

(This picture has a nice physics reference as well  :] )

Although the Bahrain World Trade Center in Manama, Bahrain, is not one of the tallest skyscrapers out there, it caught my attention because of its eco-friendliness. The BWTC is the first large-scale skyscraper to incorporate wind power into its structure, with 3 wind turbines attached to bridges in between the two sail shapes of the building. The sail shapes help to funnel wind and increase the efficiency of the turbines, which generate enough to satisfy about 13% of the tower's energy needs. 

And finishing off with two buildings in Bangkok, Thailand both designed by architect Sumet Jumsai that I like because I think they're cute :]

 Here is the Elephant Building:

And here is the Robot Building: 

Well...that's all for today. :]

Sources: http://www.burjkhalifa.ae, http://benayah.com/wp-content/uploads/2011/05/Burj-Khalifa-Dubai-full-view-a19794057.jpg, http://offtrackplanet.com/featured/the-10-coolest-skyscrapers-around-the-world/, http://upload.wikimedia.org/wikipedia/commons/6/62/E_equals_m_plus_c_square_at_Taipei101.jpg, http://inhabitat.com/bahrain-world-trade-center-has-wind-turbines/, https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_jSpJ959GGoY4NBreqm_hQaUn3Qb7EPRKyX_xvy0n8vxnt6QyRwctazJDQv-Wvn-RadPOVU9g6sYXs2mC0W8npavH6o6z_cNuxrIIH9k0HA034ANT34nK9hfOR8UoDpAOdvVINIlmNw3t/s1600/Bahrain+world+trade+center.jpg, http://www.cnngo.com/explorations/life/20-most-iconic-skyscrapers-343149?page=0,13, http://i.cdn.cnngo.com/sites/default/files/imagecache/inline_image_400x267/2011/09/22/Bangkok-elephant-building-.jpg, http://offtrackplanet.com/wp-content/uploads/2011/02/robo.jpg

Blogging Projectile Motion Homework

We had to blog our homework again...this time it was pg. 113 #22, #23, and #30. They're all about throwing/launching/falling things...

This question was about a bullet being shot horizontally from a gun...I can't really draw guns. Ah well. I realized the answer was wrong because I forgot to square root 4/9.8 ...so the right answer for time is 0.64s, and the right velocity is 207.6 m/s. I decided to blog the picture for this question anyway...the method is correct. 

I liked this question because it involved tennis :]. Unfortunately I made the same mistake that I did for the previous question: I forgot to to square root 5/9.8. The right answer for distance is 31.7 m. :/

This question was about a "lovesick lad" throwing a rock at his girlfriend (it contained a love note and she had a baseball glove, but still. Why didn't they just use email?). Yes! I got this question right. I assumed up was the positive direction, so acceleration (gravity) is negative.