|One of the Hershey Park rides a group was presenting on|
All morning in physics today groups did their presentations on their Hershey Park ride and their exponential experiments. We were supposed to keep it down to 15 minutes total, but most groups took about half an hour, so a few groups didn't get to go and will have to present on Friday. My group is one of the ones that didn't go--we were the next group on the list when Bill and Craig stopped the presentations to move on to our guest lecturer.
|The paths a beam of light would travel, as influenced by gravity|
Our guest lecturer was Mark Trodden, a particle cosmologist (oxymoron, right?). He talked about how cosmology, on the largest scale, is actually closely related to particle physics, on the smallest scale. He has recently been studying dark matter, which composes 22% of the universe and can only be detected through its gravitational effect, and believes that it is actually composed of particles based on the way it interacts in collisions between galaxies. Because these particles are theorized to interact with about the force of the weak force, though they are more massive than protons, they are called Weakly Interacting Massive Particles, or WIMPs. He also talked about how we can use the Doppler Effect on light (redshifting) to determine how fast a distant object, like a galaxy, is moving away from us. From this, cosmologists have determined that the universe is actually expanding in every direction--this acceleration is not well understood, so we say it is caused by "dark energy," which makes up 74% of the universe.
After lunch we continued working in our interest groups. My group collected all the rest of the data we needed (and got a beautiful graph, too--somewhat unusual in experimental work). Tomorrow, the last day before we present, we will work to put it all together in a presentation that we will explain on Friday. After class, I was walking out of the physics building and was accosted by an absolutely enormous wasp of some sort. It was about four centimeters (an inch and a half for you silly people out there who still don't use the metric system) long and had a wingspan about the same distance.