Podcasts: Another way to reach students!

While trying to decide what to do with my blog this week, I was also stewing over how tedious it is to teach a lesson over and over, when I realized, why not kill two birds with one stone?  Why not talk about using pod casts as a way to reach students who can't quite get it in the classroom?  Now, not to say that I don't enjoy teaching a lesson multiple times...  I currently teach the same concepts five times a day to my various eighth grade science classes.  I'm actually referring to when students are absent and need help understanding complex concepts taught in class, or auditory learner who need a little more time to absorb a lesson than others.  This past year, I had to explain how to balance chemical equations to six different students on six different occasions, not including the five times I taught it to my five different classes.  If there was a way that I could find a way to instruct my students without having to go hoarse or lose time in the process, wouldn't that be a fantastic use of technology?

I think that next year, I'll try to create pod casts for the most complex lessons so that students who are absent, or students who don't quite get it the first time can listen to it as many times as they'd like.  Perhaps this will save me time, and allow students to get the material whether they are present or not.

With that, I created my first podcast for the lesson I plan to teach tomorrow: "What is nuclear fission and nuclear fusion?"  In it, I address the learning standards that students will "explain the difference between fusion and fission, based on the energy changes" (P8C3, P8C4), and they will also "explain that in nuclear reactions, massive amounts of energy in the form of heat is generated."  (P8C3, P8C4)

http://podcastmachine.com/podcasts/13354/episodes/68338

Below is the transcript for the following podcast:

What is the difference between nuclear fission and nuclear fusion?

The topic we will be addressing in today’s podcast will address the main differences between nuclear fission and nuclear fusion.  You might be wondering to yourself, aren’t they the same thing?  If not, what is the difference and why are they important?

Nuclear energy refers to the energy that is stored inside the nucleus of an atom.  This energy can only be released during the processes of nuclear fission or nuclear fusion.  Both types of reactions release energy that can be converted into usable forms like light, heat and electricity.  Both can be used in nuclear weapons, but that’s about where their similarities end. 

Nuclear fission is when a massive atom splits into two or more smaller atoms.  This process does not occur naturally, but we humans have seemed to make it happen.  In 1934, physicist Enrico Fermi proved that atoms could be split through fission, and that some of the sub-atomic particles released as the atoms broke apart turned into energy.  This proved Albert Einstein’s theory that a particle traveling at the speed of light actually did equal pure energy.  You might know this concept better as the formula E=mc².  Later, as tensions around the world escalated around the 1940’s and 1950’s, scientists took the technology of fission further to develop nuclear weapons. 

In fission, the nucleus of an atom is struck by a colliding proton or neutron, and the nucleus breaks apart into smaller pieces.  These highly radioactive pieces go flying off in every direction, striking other nuclei, thus creating a chain reaction.  The entire process occurs quite quickly, lasting only a fraction of a second.   Now, not every atom will split when it is hit with a colliding sub-atomic particle though.  In order for an element to undergo fission, the atom’s nucleus must be larger than the element iron.  The reason for this is that elements smaller than iron are generally more stable, and are unlikely to split apart when hit, if they are even hit in the first place.  But I digress.  If the reactions are not controlled, and are left to split as quickly as they can, an atomic bomb has been created.  When the reactions are carefully controlled, however, they can be used to safely generate electricity that powers entire cities. 

In a nuclear power plant, fission of Uranium-235 isotopes is regulated by control rods that prevent the reactions from going out of control.  The number of reactions determines the amount of heat energy that is produced, and without them, the plant might suffer a nuclear meltdown.  The heat energy that is produced through the process of nuclear fission is then used to boil water in the core of a reactor that eventually spins a turbine, thus generating usable electricity.  

For atoms that are smaller than the element iron (those that will not split), they might undergo the process of nuclear fusion.  This is the process of fusing two or more nuclei together to form a larger atom.  Fusion requires atoms that are smaller than the element iron, because any element bigger than iron would become too large and therefore too unstable to stick together once the nuclei collided.

As the nuclei of atom fuses together, an ENORMOUS amount of energy is released.   The amount of energy released is actually 3-4 times greater than that released during fission.  Because of this, scientists have been working for over 60 years to try and control nuclear fusion with the goal of generating usable electricity.  Unfortunately, they have not yet found a way to create self-sustaining nuclear fusion here on Earth.  What they have managed to do, however, is to perfect the Hydrogen bomb.  In an H-bomb, two hydrogen isotopes fuse together, releasing 17.6 Megaelectron Volts of energy.  While this in itself is not a ton, the process altogether is promising because it generates 10 times the amount of energy actually needed to start the reaction.  The reason why so much energy is needed to start it is because the nucleus of an atom has a positive charge.  When it gets close to another nucleus, they repel.  You need a lot of heat and a lot of speed to make these particles collide and stick, but the reward is worth it.  In nature, nuclear fusion is the power behind our sun and other stars.  Inside them, hydrogen atoms fuse together to create helium and other heavier elements, which burn brightly, emitting energy in the form of electromagnetic waves that we can use here on Earth.  Finally, the process of fusion creates less radioactive waste than nuclear fission does, making it a potentially safer energy source in the long run. 

Well, that’s it for today’s lesson on the differences between fission and fusion.  Hopefully you’ve learned a lot, but here are the most important things you should remember:

1. Fission is the breaking down of a large atom, while fusion is the joining of two or more smaller ones.
2. Fission does not occur naturally, while fusion is what powers the sun and other stars.
3. Both are in nuclear weapons, but fusion produces 3-4 times as much power as fission.

Until next time, this is Mrs. Hallman saying good night, and happy learning!