There is no way that the House bill to prevent federal funding to NPR will get past the Senate, let alone the president's veto, but it is still an interesting discussion. We should be able to question, and have the chance to justify, the funding of anything with our tax dollars.
In case you didn't listen to the podcast (GO LISTEN TO THE PODCAST!) they start by defining public radio as a "public good". There are two criteria for something to be considered a public good:
It must be non-excludable - there is no way to stop people from using it.
It must be non-rivalrous - its use by one person does not prevent its simultaneous use by another person.
Other common goods include roads, national defense, police, and so many other things that we take for granted. Not all public goods, however, are actually "good". One of their guests uses the facetious example of a stink bomb as a public good. There's no way you can prevent someone from enjoying the odor, and any number of people can enjoy the odor at the same time. The decision to use tax dollars to fund public goods has to be based on what we value as a community.
Their conclusion is, well, inconclusive. On the one hand NPR could probably get along without federal funding. I know that if NPR lost funding and couldn't find it elsewhere I would do my part by increasing my monetary support of my local station, and I think there are many other listeners and underwriters who would do the same thing. Local stations in areas with smaller populations might suffer, however, and that would be a shame.
On the other hand, if federal funding remains, or, dare I say it, increases, there's no doubt that they will continue to report interesting, objective stories that you can't hear anywhere else. Like this recent report by NPR and ProPublica about the military's diagnosis, treatment, and tracking of traumatic brain injuries (or lack thereof), which has resulted in the Army reevaluating its policy and practices regarding Purple Hearts for victims of concussion injuries.
I certainly hope that NPR stays on the air. I don't know how I would get through my commute without it.
Today we built a very important part of the cloud chamber apparatus: the magnetometer. This instrument will allow us to measure the strength of the magnetic field on the surface of our plate where the cosmic rays will be detected.
It's important to know the strength of the magnetic field so that we can calculate the momentum of the particles. The greater the magnetic field strength, the more the charged particles will curve.
The construction of this apparatus required a lot of soldering, at least for someone who has never soldered before, like me. Not to toot my own horn too much, but I think I did a pretty darn good job. Decide for yourself:
The magnetometer has a Hall Effect Sensor which has current running through it. The sensor is attached to a voltmeter, and when the sensor is inside a magnetic field the voltage changes, depending on the direction of the magnetic field. A change in 1 mV in the voltage is equal to 1 guass. The difference be the normal voltage and the experimental voltage gives you the magnetic field strength. I found the max field strength near the center of the magnet to be about 740 gauss (the Earth's magnetic field is about 0.5 guass).
We had a picnic lunch outside the physics building, and when we came back in we were ready to cool down our chambers for the first time. I didn't put enough alcohol in the ice box or in the reservoir in the tank, so I didn't see anything at first, but when I fixed those problems I started to see some tracks.
I wonder if a lot of the particles are being blocked because we are in the basement of a large building. Maybe when I take it home or use it at school we will get more tracks.
Someone decided we needed a radioactive source so we would be able to see a lot of tracks. We used the calibration source of a geiger counter to shoot gamma rays into one of the chambers. Here's what it looked like:
In that clip you should see the "cloud" which looks like fog or rain. If you look carefully you will see wisps in the cloud, which is caused when a cosmic ray ionizes the alcohol.
This isn't my chamber, but they are all basically the same. This video was shot at 720p, and I wish it could be a little clearer, so the next time I'll try 1080p, and probably 720p at 60fps after that.
Yesterday we didn't do much building at QuarkNet. On Tuesday there weren't enough supplies for each of us to build two alcohol reservoirs, so many of us spent a few minutes in the morning building or second reservoir.
The magnets arrived yesterday, and after lunch we installed them. Each magnet is about 6 cm by 12 cm, and I am pretty sure Helio said they are about 500 gauss. It was a simple install. They had brackets already made and holes already drillled. All we had to do was add a little silicone adhesive to help hold it in place and screw the bracket to the underside of the plate. See?
This magnet will create a magnetic field (duh) in the alcohol fog, which will cause the charged particles to travel in a curved path. Negative particles will curve on way, and positive particles will curve the other way. The amount that the particles curve depend on the mass of the particle, so by studying the particles path we will be able to calculate the momentum of the particle.
The rest of yesterday was taken up by a very interesting lecture by Helio, and a Q&A session in the afternoon. Helio's lecture was great. He is a soft spoken man, with a good sense of humor, and he is incredibly knowledgeable. Better still, he is good at explaining things and is very patient. We learned a lot about particle physics, which is my favorite aspect of physics.
Today we are going to build the magnetic field sensors, and I really hope we'll get to make some clouds today. I saw someone bring in some dry ice, so that's promising.
Today at QuarkNet we built a reservoir for the alcohol. One of the teachers who has been involved with QuarkNet for a while had the PVC already cut for us, we just needed to assemble it. The reservoir has magnets on each end, which will be attracted to magnets on the outside of the tank. The magnets are offset a little, so that as the tank is turned upside down the top of the reservoir always points up. This is going to make it incredibly easy to load alcohol into the chamber.
Here's the reservoir:
There's felt inside which will increase the surface area of the alcohol to aid in its evaporation.
After lunch we assembled the light strip that we'll use to illuminate the fog, making the tracks easier to see. Another QuarkNet veteran prepared the wood and provided us with excellent instructions. We had to do a little wiring and soldering, but it was pretty easy.
Here's the light strip:
and illuminated:
Added to the setup from yesterday we have:
Tomorrow we'll build sensors to measure the magnetic field on the surface of the plate. I guess we'll also add the magnets. Maybe we'll even be able to make some clouds.
I'm participating in QuarkNet 2010 this week at Stony Brook University. QuarkNet is a workshop they have been running since 1999 (I think) for high school physics and chemistry teacher, and pre-service teacher as well. This year each participant is building a cloud chamber which we'll use to measure the momentum of cosmic rays.
I took class at Stony Brook while I was a grad student there with the same professor who is running this workshop, Helio Takai, and in that class we were working to improve a previous cloud chamber design. It was a really fun class (for which there were no assignments or homework) but there was only one cloud chamber. In this workshop we are each building one, and we get to bring them back to our schools for demonstrations next year.
Here's the basics about how the cloud chamber works:
A metal plate is placed above a styrofoam cooler filled with dry ice and alcohol. Metal feet/legs extend down from the plate into the solution to conduct heat out of the plate. On top of the plate is an upside down fish tank, with a reservoir of alcohol in the top of it. There is a temperature gradient between the cold metal plate and the top of the fish tank at room temperature, which causes the alcohol to evaporate and then condense in a layer about an inch think at the plate.
This "cloud" is supersaturated, and when cosmic rays (electrons, positrons, protons) pass through the fog you can see their trail. A magnet is added under the metal plate to create a magnetic field, which affects the path of the charged particles that pass through the cloud. By filming the cloud chamber in operation for a while we will be able to extract frames during which an interesting event happened and calculate the momentum of the particle.
I always figured that if God did exist, and if he was a reasonable God (a lot to ask, I know), that I'd be okay because I try to be a good person, for no other reason than I think it's the right thing to do.
People are not going to like this, but something has to be done.
The price of gas has to increase. We can wait for the supply to diminish to the point that the market raises the price, or the government can levy higher taxes to manipulate the price at the pump. Gas should be at least $5 per gallon. The money raised by taxes can go to support R&D for alternative energy sources, and the higher cost of travel will encourage people to conserve by buying fuel efficient cars, car pooling, taking public transportation, walking/cycling more, or by simply traveling less.
Encourage the production of more nuclear power plants now that the moratorium is over. Nuclear energy is not the long term solution, but it is a major step in achieving oil/coal independence. There are so many reasons to build new nuclear plants:
The moratorium didn’t shut down old plants, so now we have 104 nuclear power plants operating in this country that are at least 30 years old.
New nuclear technologies have been developed that are more efficient than old technology. This means that the energy they produce is cheaper.
Safety is the biggest concern of opponents of nuclear power. New nuclear technologies are safer than the ones currently in use.
The storage of spent nuclear fuel is not as dangerous as people make it out to be. Read Richard Muller’s book “Physics for Future Presidents” for more information.
In America, more people have died working in the coal industry this year than have ever died working in the nuclear power industry.
Three Mile Island was a success, not a failure. Of course things might go wrong; people make mistakes and equipment malfunctions. That’s why there are so many backup systems and safety measures in place. The events at Three Mile Island showed us that those systems work.
Public and private sectors both need to invest in wind and solar energy. My money is on solar energy, but current technology is very expensive and minimally efficient. Over the next 50-100 years, solar cells will get cheaper and more efficient, and we will either incorporate them into structure we already have (solar shingles for instance) or build large solar farms, or both. After the initial investment this energy is essentially free, requiring fees only to maintain equipment and eventually replace it. No burning of fossil fuels, no storing or nuclear waste, just cheap, clean electricity.
All of these steps need to be taken in order for us to have the energy we need. If we choose to start now, the process will be less painful. If we wait, times are going to be tough. Some countries are already on step two, so if we want America to be an important player in the energy market a hundred years from now we have to start playing catch up. I think we can do it if we stop letting politics get in the way of things that really need to get done. I fear this might be too much to ask for.
