It was truly a very fascinating night, and not to mention, COLD.
For the first time in my life I really saw the moon with my own eyes, the craters, mountains and the bright spots of light reflecting back from it. Nonetheless, not only did we get the opportunity to see the moon, but we also saw the two planets Neptune and Saturn. To add to this, we also were able to spot out the Wild Duck, The Big Dipper, Vega, Polaris and not to forget the moving clusters of stars that rotate around our galaxy. It was very exciting and I most definitely learned a lot about the different constellations and stars.
Friday 28 September 2012
Hot Air Balloon
What can one create with
recycled straws, tape, candles and a ginormous plastic bag? A hot air balloon
of course! Once again, the class begins to work and construct a structure that
is made solely of ordinary materials at home. This time, it is required that we
make a hot air balloon rise 5 cm for 20 seconds (or 0.20s). Was it really
possible?
Our Basic Idea
The idea behind our hot air
balloon was to make sure that no heat escaped from the balloon except from the
hole at the bottom the base (which was purposely cut there). We hoped that if
there was a lot of heat trapped in the inside the balloon would rise for sure. We used the top part of the structure from Egg Lander attempt 2 and carried out our plan.
Results
10 seconds after lighting
the candles, it was apparent that our hot air balloon was not going to work.
For one, the bag was beginning to melt! We did not even think that maybe the
bag would be too close (and small) and the flames from the candle would have a
drastically negative effect on the structure. Also, we used a lot of tape and
cardboard paper. This added unnecessary weight and this was also another factor
as to why the balloon did not work.
Egg Lander, attempt 2
So,
everyone deserves second chances right? It was round 2 for our egg landers
to transport the egg to the bottom of a two storey fall safely. Were the results
positive?
Results
Our
second attempt at the egg lander mission was a great success! Our idea was to
place the egg in between an hour glass shaped structure. This ensured three
very important things: security of the egg, when the contraption lands, it will
fall on either side and most importantly, no straws were touching the egg
directly. In my first egg lander, the egg was loose and came off the structure just
before hitting the ground. I wanted to make sure this did not happen and so
this time the egg was 100% secure. Next, in the previous egg lander, the
structure dropped in the exact opposite direction from what we wanted. Thus,
the idea behind the hour glass is to make sure it can land on either side
safely. Finally, after the major emphasis on “egg should not have direct contact with straws” (which by the way
was true for my last lander as well) we once again decided to not allow the egg
to touch the straws. Furthermore, we attached 3 extra straws to edge of the self-called
“top” of the egg lander because this would slow down the speed of the lander as
it dropped.
Sunday 16 September 2012
Egg Lander
Dropping eggs off a two storey high building may sound like a lot of fun, but when it has to be dropped without any cracks, well, this becomes a whole new story.
Our design
The design we came up with
consisted of a tetrahedral elevated over a large, sturdy square base. This was
an excellent idea because when the lander is dropped, the air would just pass
through the base, and when landing, the large base will take the impact leaving
the egg intact. The idea of the pyramid was to cover the egg from all four sides, and we even placed the egg in a capsule and stuffed it with tiny straws;
making sure the egg was secure. With all these ideas that seemed so practical,
we were sure that the egg lander would work…but we were wrong.
Results
A split second after Eric threw
the egg, everyone knew something was incorrect. For one, the entire structure
had turned upside down. This was a serious issue because we had intended for it
to land on the base, but now the structure was going to land “egg first”, splat,
onto the cement below. Another reason why this action basically declared the
egg as a goner is because we never placed a lid on our capsule that the egg sat
in. This is because we never had thought that the structure would turn around.
Now, the big question that
resides is: why? Why did our challenge go horribly wrong? Well I believe there
are three possible reasons for that. First of all, the impact was much greater
than anyone expected. We miscalculated how fast the egg would accelerate and
how strong the impact would actually be because even though we had extra straws
left over we did not use them. Those straws could have been used to save the
egg (and our dignity) by allowing it to share the shock factor and adding
weight to the bottom. Secondly, the placement of the egg was completely wrong.
In the structure, we placed the egg towards the middle of the tetrahedral. By
doing this, we did not realize how much weight we had added to the top of the
structure, which caused it to turn the opposite direction. Lastly, a flaw in
the design led to the destruction of the egg. For example, when making the
elevated pyramid, we attached the top point by simply taping the ends together.
We had forgotten the physics behind the structure because if we had made the
top point longer, the impact would have been distributed among the straws and
the egg would obtain less of a disturbance. Furthermore, we needed to better
protect the sides if our tetrahedral in order to minimize the shock factor.
Changes and Modifications
For a better and more successful
egg dropper, I would make three substantial changes. The first one would be
that I would adjust the top point of the pyramid and make it longer. This would
decrease the shock factor and the egg could have a better chance of surviving. Secondly,
I would attach the egg itself lower into the structure. I would change it so
that the egg is at the bottom of the pyramid to the middle of the base
structure. This would ensure that the structure does not flip over as most of
the weight would be at the bottom. Lastly, I would add further support and
protection to the base of the structure. Adding more weight to the bottom and
ensuring the straws share the impact and not the egg.
Subscribe to:
Posts (Atom)