How many lectures and seminars have you attended that sounded a lot like this one?

Visualizing π in motion.

One of the harder concepts I grappled with when I was a kid was pi. Where on earth did that number come from? Now, we know the answer to that, but a very good way of visualizing it has surfaced on Wikipedia. In essence, it's an animation of a circle rolling out once. If you measure how many diameters the roll covers on the ground, you get pi.

This is the classic basic chemistry experiment: a (very!) small piece of sodium is dropped into a water beaker. The violent reaction causes the sodium to ignite and whizz on the surface of the water. The reaction is very exothermic, meaning it releases a lot of heat, and produces sodium hydroxide, which makes the water turn alkaline. This is a dangerous experiment if done wrong.

So post World War II, the USA had a few tons of sodium to dispose of. How did they do it? By dumping it in batches into a lake. The lake was already alkaline, so not (too) much harm there. But the beauty of this is the demonstration of just how violent the reaction between sodium and water is: it's explosive, even if the water is icy cold. With this little intro, I leave you with the video below:

Technorati Tags: science experiments

Moon Experiment

One of the most famous science experiemnts attributed to Galileo, was him going up the tower of Pisa and dropping two balls of different masses from a height. The experiment was meant to show that the balls reached the ground at the same time - i.e., irrespective of their differing masses.

Earlier this month, someone posted the NASA video of this experiment done on the moon. It's a very cool short clip of what really happens when you take away the effects of air resistance from this experiment. David Scott and Jim Irwin conducted the experiment on the Moon during their Apollo 15 mission.

I've embedded the video below, and you can download the original source from NASA's website.

Technorati Tags: Galileo, NASA, video

This is a great video by the one and only David Attenborough about how crows in Japan have devised a clever way to eat nuts, a food that they naturally wouldn't be able to eat otherwise.

Technorati Tags: video, crows, nuts, David Attenborough

Note: This is an experiment in putting videos on blogSci.com. I would love to hear your comments/feedback about this. Thanks!