## Posted tagged ‘Physics’

### A Shocking Lesson

March 14, 2010

Static electricity is an electrifying experience! Sometimes, when you come in contact with a piece of metal, you can receive an electric shock, particularly if you are wearing rubber shoes (like sneakers or runners). Why?

Well, the reason is that you are storing an unbalanced charge. If you remember from our previous studies of the atom, most atoms have no net charge; they have the same number of protons as electrons, and thus have an overall charge of zero. How do you get an excess of charge? Well, that means you have more or less electrons than protons (you can’t gain more protons without changing your nuclear structure, so you must gain or lose electrons.)  and thus you are charge imbalanced. As soon as you touch (or even come close enough that a spark can jump to) another object, the charge will move so that it is more evenly balanced across the two objects. This is called static discharge and can be quite painful! In fact, the average human body can store approximately 3.5 kV of static charge!

### Want some salt with your Fission Chips?

February 28, 2010

Nuclear Fission is an amazing process. With a fuel that is inert (even enriched uranium won’t burn in a flame), the input of a single neutron can cause the release of more energy than tonnes of explosive.

How does a single neutron do this? A single neutron initiates a reaction which causes the release of more neutrons, each of which can initiate further reactions. This process is called  a chain reaction, as the individual events in the reaction are caused by previous events.

You can envision a chain reaction as a snowball rolling down a mountain, picking up more and more snow until an avalanche is unleashed.  You can model how a single change can cause a cascading sequence of events by playing this game (Can you beat my top score of 1170? Provide a screen shot if you expect me to believe you!).

So what does a chain reaction look like? Well, because of the size of the particles involved, the speed and energy of the reactions, we can’t actually see the individual events (fissions). If you want to see what it looks like, check the Tsar Bomba update on the Boomology post. We can theorise what they look like from what we know how they work, and we have various simulations:

### Boomology – The science behind nuclear explosions (updated with Tsar Bomba!) (updated again!)

February 16, 2010

The world was changed forever in 1945. The Manhattan project tested the first ever “atomic bombs” and the power that was contained in the nucleus was unleashed. The first ever atomic bomb blast was a test called Trinity, detonated on July 16th in New Mexico, USA.

It was called “The Bomb” and its effects still change the world today. The “nuclear powers” of the world are those nations that have (or are suspected to have) nuclear weapons. Ever since the first military detonation (Hiroshima), the nations of the world have sought to prevent the further spread of this deadly technology. Depending on who you consult, you will get explanations ranging from desire to maintain the nuclear nations’ political power through to altruism to remove the risk by destroying all nuclear weapons. The total nuclear arsenal of all nations is more than enough to destroy all life on earth many times over. Despite this danger, some argue that the nuclear bomb technology has been the greatest force for peace in modern history; that without it many more conventional (non-nuclear) wars would have been fought, or that World War two may have continued for many more years, resulting in even more loss of life.

### Don’t get active, GET RADIOACTIVE

February 11, 2010

When “people” talk about radiation, it is almost always with concern. Whether it is “radiation from mobile phones/towers”  to “a bite from a radioactive spider” to “radiation from microwaves” the concern is always there. But what is radiation exactly?

Well if you use google and type in “define: radiation” the first response is:

Energy that is radiated or transmitted in the form of rays or waves or particles

So, for example, any object that gives off heat (a form of energy) is radiating! This means that you are a source of radiation!

But that’s not what we are talking about in this unit – we are specifically talking about nuclear radiation, which according to movies apparently causes things to glow green and possibly develop superpowers (exposing yourself to radiation to try and become Wolverine is not recommended!)

But this is not the way nuclear radiation actually works (suprise suprise, movies have gotten it wrong again. And again. And again! Maybe they should just give up…). Amazingly enough, after just two weeks of Physics, you know more about radiation than 90% of the Earth’s population!

Here is a slideshow that covers more than what you need to know (up to slide 34 is the end of the current topic)