## Archive for August 2008

### Poster boy!

August 27, 2008

Well, we finished the project on posters and all of you should be receiving you posters back shortly. One person however did not submit a poster, but did do the following:

Excellent Effort! (direct link to file)

And a link to a previous post that talks about colour and the E-M spectrum

See you in class!

### Rockin' Roller Coaster Physics

August 17, 2008

Energy is an unusual concept in physics. Physics defines energy as the ability to do Work. Hyperphysics explains the concept of Energy as a “currency” of work:

Energy is the capacity to do work; You must have energy to do work, it is like the currency for performing work. To do 100J of work, you must expend 100J of energy.

Energy can be in many types – there is the energy of movement (Kinetic Energy), and energy of sound (Sound Energy), Light Energy, Heat Energy, Electric Energy and so on. There is another type of Energy, Potential Energy. This is “Energy waiting to happen”, or stored energy. Some examples of this are Gravitational Potential Energy and Elastic Potential Energy.

What do we mean by Potential Energy (Stored Energy or “Energy waiting to Happen”)? Well the best answer to that involves a concept called Conservation of Energy, which states:

Energy in a closed system can neither be created nor destroyed, it merely changes forms.

This is actually a complicated concept. It does not mean that objects cannot lose a type of energy, i.e. objects cannot lose kinetic energy, but that if they do lose one type of energy they must gain another type of energy. For example, an object shot upwards gradually slows down (thus losing kinetic energy), but as it does, it gains gravitational potential energy – it has energy ‘stored’ by its position above the surface. If it were to be stopped at the maximum height (for example by sticking to a ceiling), it could later fall, and thus gain kinetic energy again. The kinetic energy it had was “stored” until it began to fall again.

### She Cells Sea Cells?

August 2, 2008

Cells are the fundamental structural unit of almost all life. There are some forms of life such as viruses (virii) and other so-called “non-cellular” life, but everything else is based on and formed from cells. This is called “Cell Theory”.

1. All organisms are made up of one or more cells
2. Cells are the fundamental structural unit of life
3. All cells come from pre-existing cells

This is the “Classical Theory”. The modern theory is somewhat more complex, but we will not be studying that as part of this unit. The eventual focus of this unit is the genetic factors affecting inheritance, and when we have time, Evolution. In order to understand these complex ideas we will be building up from the basic structure of cells, through cell division, DNA structure,introductory protein synthesis and thus to genetic expression.

The first thing you must learn is the structure of a standard eukaryotic cell, with the names, functions and locations of the various organelles. The website “Cells Alive” will help you study and learn this information.

The next thing is cell division – the processes of mitosis and meiosis. I reccommend the following site as an excellent animation of the phases and operations occuring during these processes; John Kyrk’s Animations.

And finally, some rap:

See you in Class!