Monday 26 September 2011

DIY Atomic bomb?

A Swedish man named Richard Handl was arrested in late July for "trying to split atoms in his kitchen," as several media outlets put it. According to Handl's blog, the 31-year-old chemistry hobbyist obtained samples of radium, americium and uranium and was trying to set up a makeshift nuclear reactor on his stove.
Handl apparently didn't know that his DIY activity was illegal. He wasn't caught until he sent a question to Sweden's Radiation Authority and was answered in the form of a police visit.

Kent Hansen, professor emeritus of nuclear science and engineering at the Massachusetts Institute of Technology, thinks not. "My guess is that this is a tempest in a teapot," Hansen said, referring to the media storm surrounding Handl's arrest rather than what the Swede may have been brewing on his stovetop.
First off, Handl didn't have the right raw materials, according to Tom Ewing, a nuclear scientist at Argonne National Laboratory, outside Chicago. "As best I can tell … he only possessed minute amounts of radioactive materials: radium from old watch hands (from antique devices purchased on eBay) used in the old days to make dials 'glow' at night, americium used in trace amounts as an ionizing source in ordinary smoke detectors you buy at hardware stores, and depleted uranium (who knows where he obtained this)," Ewing said by email.

None of those were going to work. Radium doesn't fission, or split when bombarded with neutrons. To make americium work, you need a complex nuclear reactor, and depleted uranium contains scant amounts of the right variety for nuclear fission: U-235.
The vast majority of uranium in nature is another kind, U-238. "To make a reactor you have to separate out U-235 from U-238, but to do that you need something the size of centrifuges or fusion points," MIT's Hansen told Life's Little Mysteries. "These are enormous industrial facilities. There's no way someone could do it in their kitchen."

Ewing pointed out that the difficulty in enriching uranium is why so few nations have the ability to make fuel reactors. "Not a thing that you can do in your kitchen!" he wrote.
In short, Handl probably didn't have the right materials to set off a fission reaction. But what if he — or you — did? How could you get them to react?

Let's pretend you have access to pure U-235. "To make it fission, you need neutrons," Hansen said. Because your kitchen doesn't include a nuclear reactor, which uses something called a moderator to bring neutrons into contact with uranium, your only option is to pack together a critical mass of the stuff.
"You could bring together enough nuclear material to make a critical mass so that the neutrons from fission would produce more fission and sustain the reaction," Hansen said. "To do that you need a sphere of pure U-235 a foot across."

So just pack a wok full of U-235. It'll cook on its own.

There's one little problem: "If anyone had that much and tried to bring it together, they would kill themselves," Hansen said. "It will fizzle, not make an explosion, but it will produce enough radiation to kill you."

The above article is taken from Life's Little Mysteries. 

STD slides

https://docs.google.com/leaf?id=0B61FLI2_Iqx0ZjM4NmI3ZTYtYjQxMy00ODNkLThiYmUtNTY2ZWY3MjI3MjE3&hl=en_US

Wednesday 14 September 2011

Very Important!

Here are the links to the first parts of the videos of "Black Rain White Light" and "Barefoot Gen".

Apologies for the lack of time in class to show you all the videos, but please do view all parts in your own time. You can search for the links for the rest of the video on the right side.

Black Rain White Light
http://www.youtube.com/watch?v=PqEcJZ43Tik

Barefoot Gen
http://www.youtube.com/watch?v=sCK4arVflHE&feature=related

Monday 12 September 2011

Welcome back

To a new (and very short) semester!

This week we are starting on the Atomic bomb (no, not making it). Before you present your projects, we will be viewing the movie "Fat Man and Little Boy".

The following PDF is an article written by Richard Feynman, who is a physicist and was part of the team of the Manhattan Project.
http://calteches.library.caltech.edu/3090/1/FeynmanLosAlamos.pdf

Good luck for the project.

Monday 5 September 2011

Something interesting on the Manhattan Project

Ever wondered what "The Mahatten Project" was about?

The following website links directly to the people involved in the project
http://intergate.cccoe.k12.ca.us/abomb/responsible.htm. Are you able to guess what the Manhattan project just by viewing this page?

Do navigate the website to gain more info - would probably help immensely in your a-bomb project!

A very big THANK YOU

Hi guys,

Thank you very much for a wonderful teacher's day in RI. It's been a great pleasure seeing your appreciation for the teachers who have taught you, and a very huge encouragement!

Special thanks to the boys who have given me presents; your gestures meant enormously to me.

Meanwhile, have a great holiday, and I am looking forward to seeing all of you already :)

Friday 26 August 2011

Life Science Slides - GE link fixed

Central Dogma
https://docs.google.com/leaf?id=0B61FLI2_Iqx0YzZmYzgzYzQtNmU2MS00ZTk0LWFkNTYtYzAwYzVhYTQzZDY3&hl=en_US

Transcription Video


Translation Video


There are also many other good animations out there - do take a look at some of them.

The following video shows DNA replication - the next part of the Life Science topic we will be covering in the next lesson.



Genetic Engineering Slides
https://docs.google.com/leaf?id=0B61FLI2_Iqx0NjgxNDk5ODctODM0ZS00NWY1LThlYzgtMjRhMDExYzA0M2Zh&sort=name&layout=list&num=50

Wednesday 24 August 2011

ATOMIC BOMB Project - link fixed

Hi guys,

I know you have all been waiting for this. Sorry for deseminating this only now, but don't worry, there is definitely ample time, and all factors will be taken into consideration when grading. Further details will be explained in class next week, and I will be giving you some time to come together in your groups to discuss.

https://docs.google.com/leaf?id=0B61FLI2_Iqx0ZWU4ZDRiYTEtMGRhZC00ZTdhLWFlNmUtZjkyYmE1ZTQ3YTI5&sort=name&layout=list&num=50

The other relevant learner outcomes and worksheets on atomic bomb after-effects will be given out during Term 4. If you can, go borrow and watch the movie "Fat Man and Little Boy".

Good luck for the assignment!

Wednesday 17 August 2011

Survey on Teaching and Learning of Science

Hi all,

This last term of teaching you have been eventful, and I have learnt a lot from you boys. Now that we are coming to the end of the term, I would like to have your feedback on your science lessons so that I can understand your learning needs better, and improve on my teaching.

Please complete the survey in your own time at the following website: https://spreadsheets.google.com/spreadsheet/viewform?formkey=dGsyRVZHNDZ1UXBJYVJZemFLcjZfdkE6MQ.

The last date of completion of the survey is 31 August 2011.

Thank you very much for being my students this term - I've enjoyed my time with all of you :)