Hot Air Balloon..... number 2!

After hot Air balloon number one miserably failed, everyone got their heads together and strategized for a new and improved idea. Since the groups were switched around, everyone began with a fresh mind and idea. In my group, we decided that we wanted to ensure that the base had the least amount of weight. This was our main focus. 

Our Idea

We intended on using a full sized bag so then the most amount of air could be trapped and since the base weighed very little (or so we assumed) the hot air balloon would rise! One of the problems we faced was that since our base was constructed with wire, we didn't have a place where we could stick on the candles. We brainstormed a bit but finally decided to add a few straws to the bottom of the structure. On this we would stick in the candles. This added a little bit of weight to the bottom, but we didn't consider it to make much of a difference as our bag was really big. 

Results

The hot air balloon did..... not work! I'ts possible that it didn't work because the weight was too much, or because there was a lot of wind that day and the candles kept blowing out or both! 

Star Gazing

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.

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.

In the end, the structure fell swiftly to the ground (while making impressive helicopter-like rotations) and all was well.    

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.