A pretty spectacular science experiment: how to make an Incredible Egg Geode.
Your egg geode is formed through a process called sedimentation. The heated alum solution contains suspended particles of alum powder and as the solution cools, these particles of alum begin settling. When the alum particles settle towards the bottom of the beaker or glass, they begin crystallizing. With the alum-covered egg at the bottom, the alum particles from the solution begin attaching themselves to the egg. Covering your egg in alum powder beforehand gives the suspended alum particles a surface to which they can more readily attach themselves. The particles that settle onto the surface of the egg crystallize, and you will also see crystallization on the bottom and sides of the beaker or glass.
This video demonstrates how to tie a Figure 8 knot, one of the Basic 8 knots that lead to a huge catalog of useful tying skills for boating, climbing, scouting, search and rescue, and more.
The Figure 8 is a stopper knot — it prevents the end of a rope sliding through a pulley or it can be used to add security to another knot. It is relatively easy to undo, is preferred to the Overhand Knot, but is not as secure as the Double Overhand.
These videos are from AnimatedKnots.com, where they believe that it’s “Better to know a knot and not need it, than need a knot and not know it.” And don’t forget, safety first!
Photographer Dan Finnerty’s time lapse view of comet Pan-STARRS over Southern California is breath-taking. The colorful sunset and moon setting doesn’t hurt either. Full screen!
The comet is called C/2011 L4 PANSTARRS, and it’s a frozen ball of dirt with a long tail made of debris. PANSTARRS isn’t coming very close to our planet –the closest it gets is 170 million kilometers, more than 400 times the distance between the Earth and the Moon. But the comet’s tail is roughly ten times longer than the Earth is wide, and as it passes through our neighborhood all that ice and dust reflects light, so the comet shines bright in the night sky.
…PANSTARRS will remain in our night sky through the end of the month.
Nasa has this helpful graphic in their ScienceCasts: A Naked-Eye Comet so that you might catch a glimpse before the view grows dim.
via Wired Science.