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In the last physics lesson, the teacher seemed to have to explain the Doppler effect for quite a long time to some people before they understood it. So, being the nice, considerate, thoughtful person I am, I decided out of the goodness of my golden heart to explain the Doppler effect for future reference using animation (actually, I thought it would be a fun thing to do anyway). For those of you who are confused about what the Doppler effect has to do with anything, it's red shift and blue shift. So it is relevant to the lesson.

The Doppler effect (or Doppler shift), named after Austrian physicist Christian Doppler who proposed it in 1842, is the change in frequency of a wave for an observer moving relative to the source of the wave. It is commonly heard when a vehicle sounding a siren or horn approaches, passes, and recedes from an observer. 

Instructor Blaine Greenhalgh explains the doppler effect. Good animation of man walking with a light globe.

"http://yt.cl.nr/gjsMV1MglA4" I stick my hand (momentarily) directly into liquid nitrogen but don't suffer any injuries due to the Leidenfrost effect.

The Cambridge IGCSE Physical Science syllabus helps learners to understand the technological world in which they live, and take an informed interest in science and scientific developments. They learn about the basic principles of Physical Science through a mix of theoretical and practical studies. Learners also develop an understanding of the scientific skills essential for further study at Cambridge International AS and A Level, skills which are useful in everyday life. As they progress, learners gain an understanding of how science is studied and practised, and become aware that the results of scientific research can have both good and bad effects on individuals, communities and the environment.

The evolution of the peppered moth over the last two hundred years has been studied in detail. Originally, the vast majority of peppered moths had light colouration, which effectively camouflaged them against the light-coloured trees and lichens which they rested upon. However, because of widespread pollution during the Industrial Revolution in England, many of the lichens died out, and the trees that peppered moths rested on became blackened by soot, causing most of the light-coloured moths, or typica, to die off from predation. At the same time, the dark-coloured, or melanic, moths, carbonaria, flourished because of their ability to hide on the darkened trees.

" Dim Lights Share a clea.nr URL: Hide Comments, Favorites, Suggested Videos, etc. There is a common perception that weight and mass are basically the same thing. This video aims to tease out the difference between mass and weight by asking people what makes a car difficult to push. The standard answer is that it is difficult to push because it's heavy. But heaviness is a measure of weight, the gravitational pull of the Earth attracting the car to Earth's center. When the car is pushed on a flat road, the force of gravity does not oppose the motion. Instead the resistance felt is an indication of the car's mass which determines its inertia. Inertia is the property of matter that means it tends to resist acceleration - the greater the mass, the less the acceleration for a given amount of force. Subscribe 109 videos 32,519 Like Add to Share Uploaded by 1veritasium on Feb 7, 2011 There is a common perception that weight and mass are basically the same thing. This video aims to tease out the difference between mass and weight by asking people what makes a car difficult to push. The standard answer is that it is difficult to push because it's heavy. But heaviness is a measure of weight, the gravitational pull of the Earth attracting the car to Earth's center. When the car is pushed on a flat road, the force of gravity does not oppose the motion. Instead the resistance felt is an indication of the car's mass which determines its inertia. Inertia is the property of matter that means it tends to resist acceleration - the greater the mass, the less the acceleration for a given amount of force. 320 likes, 14 dislikes Show more Uploader Comments ( 1veritasium ) Actually, it is the friction which is causing difficulty in moving the car. Ideally if there is no friction, whether rolling or sliding, even the slightest of the force would make the car move. You could actually be able to move the car with a push of your little finger if there is no friction at

The scale of the experiment matches the scale of the intellectual leap achieved. A huge apparatus, 27 kilometres in circumference, buried 100 metres below the French-Swiss border near Geneva, accelerated particles in a near-perfect vacuum to speeds just below that of light and measured the effect of their collisions. Minute variations in energy released prove the existence of the Higgs boson, which had been postulated in theory by Peter Higgs in 1964 to explain the mass of elementary particles. Wednesday's discovery, published by two separate groups of researchers working in isolation from each other, can be compared with the discovery of DNA, or Einstein's theory of relativity, or the splitting of the atom. Achievements such as those are like peaks in a mountain range. They draw the world's attention, but really it is the great mass of the range itself that holds the peaks up which has more significance. Without the massive bulk below, the peaks would not reach so high. For science that great mass is a huge amount of lead-up work. The standard model of particle physics is the work of many hundreds of researchers, only one of whom was Professor Higgs. That achievement sits within the millions of achievements of the wider research effort of the whole science community. And that is enclosed, too, within the wider community which understands and supports what science has achieved and can achieve. Read more: http://www.smh.com.au/opinion/editorial/science-gets-a-chance-to-show-the-way-20120706-21mf2.html#ixzz21rjUGfs0