Cannons

A cannon is any piece of artillery that uses gunpowder or other usually explosive-based propellants to launch a projectile.
 

A Cannon is a device that uses an energy source (usually gunpowder) to launch an object in a projectile motion.

• A friction primer is used to ignite the black powder that is in the tube. The friction primer consists of a hollow tube that fits into the vent hole. At its top there is an opening through which a serrated wire can be inserted. The wire has a loop on it through which a lanyard, or rope, is attached.

  When it is time to fire the cannon the rope on the friction primer is pulled. The serrated wire creates enough heat from friction to ignite the black powder that is in the primer tube. This fire ignites the black powder in the breech. The explosion that results from the breech powder being ignited propels the projectile out the end of the tube.

Newtons Lab results

"In theory"

Thus far every hands-on creation I've conceptualized has failed dismally. Because despite every speculation that it would work "in theory", i'm gradually begun to realize that things are different in practice.

Today's challenge was a tower made out of three pieces of paper and about 50cm of masking tape. We were told to build the tallest structure we could. So we came up with the idea of a "cootie catcher" as the base and through ~rigorous~ testing we realized that we can maximize the height of the rolled up news paper if we cut one sheet of our square news paper into 4 separate squares and then fold it diagonally. But as we assembled our structure we realized we did not have nearly enough tape to tape the long stick of newspaper through the center of our cootie catcher, and in fact, the cootie catcher did not weight enough to be the center of gravity, hence our dismal failure.


"in theory" it seemed like a fool-proof plan.
i should just seek a career in janitorial studies or smth////

haiku;

Things are much better
in theoretical form.
Things like time travel. 

Tall Architecture

The tallest structure in the world is the Burj Khalifa. It is in Dubai and its height is 828 meters.   

You can see that the base of the tower is significantly bigger than the top of the structure and it gradually gets smaller as the structure gets higher.
The architects did this on purpose so that the center of gravity of the structure would be on the bottom so that it would stand, since that is where most of the weight resides.

Another projectile motion case

Some people asked me about #9 so here it is