"Anti-helium" at The Tonight Show

Everyone knows the effect of helium gas. Who hasn't inhaled a party balloon and had fun talking like Donald Duck? Kids today are at least familiar with this phenomenon.

At Jay Leno a couple of months ago, Josh Duhamel demonstrated the behaviour of a different gas heavier than the components of air. He described it as "anti-helium", the correct name is SF 6 (Sulfur Hexafluoride). This is a nice demonstration at science shows. The gas is harmless to people (in moderate doses), but harms the ozone layer. So please consider the risks for the environment if you wish to use this demo.

Make a glowing tomato

I just saw this amazing video made by The Shooting Eggs Production, and I can't wait to try it for myself. It does not look like a fake to me. It requires three household chemicals, match phosphorus, bleach and hydrogen peroxide. The chemicals have to be strong, though (according to a comment to the video), so take care with your hands and your eyes if you want to give it a go.

Dig a hole to China, or?

It is a known fact that if you dig a hole straight down, you will end up in China. It is something we have learnt as children all over the western world, I believe. Without the hard labour, and not considering the melted magma you have to fight when crossing the core of earth, you can check this fact with this cool application made by Stienman/Micro Basics.
Considering that 70 % of the earth surface is covered with oceans, it might not come as a surprise that you will find it hard to hit land wherever you start digging. Only small parts of the landmasses are placed opposite land, like the southern part of South America and South-East Asia. If you start digging from Tromsø, where I live, you would end up midsea between South America, Australia and Antarctica. Very far from China! So who started this myth, anyway?