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How to Have a Lucid Dream

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Lucid dreaming is a state in which you know you are dreaming, and can control the dream. While it's difficult to get started (I'm still working on it), the notion of influencing your own dreams is tantalizing. There are plenty of resources on the web to get you started: How to Have a Lucid Dream is a good overview. Dream Views is a well-designed source of information and tutorials. Wikipedia has a page on lucid dreaming as well.

If you're not interested in working on your own lucid dreams, you might watch The Science of Sleep for Michel Gondry's take on dreaming.

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Watch How to Make a Compass
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Let's say the mega-earthquake comes and you're stranded with just some MacGyver-style bits and bobs. If you've got a magnet and a little knowledge, you can make a compass that reliably points north. Below, check out a vintage segment from Curiosity Show explaining how to do it—and a bit on the science of why compasses work.

In the clip below, presenter Deane Hutton shows three methods involving a mirror, cork, a pin, a drinking straw, and a circular magnet (in different combinations). There's something for everyone!

Incidentally, one of the key issues in making a compass is knowing which end of a magnet points north and which points south. One YouTuber asked how to determine this, if it's not already marked—as might be the case in a survival situation. Decades after the clip aired, Hutton chimed in via YouTube comments to answer:

Wait till the Sun is about to set. Stand with your right shoulder toward the setting Sun. You are now facing South. Suspend the magnet and let it swing freely. When the magnet stops swinging, the end pointing South is the South Pole of the magnet. Deane.

Science is cool. Anyway, enjoy:

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Watch How To Make a Self-Starting Siphon Using Bendy Straws
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In this vintage video segment from Curiosity Show, we learn about self-starting siphons. These things start a flow of water without the user having to squeeze a pump or suck on a tube, which is a distinct benefit.

In the segment, we also observe the limitations of self-starting siphons. Because the act of submersion starts the flow, we're limited to siphoning water out of very full vessels. But still, this could be useful for a home aquarium, which is one of a thousand scenarios in which you don't want to use a mouth-primed siphon.

The best part of the segment is when presenter Rob Morrison shows how to make your own self-starting siphon. File this under "Handy stuff you can do with bendy straws." Tune in and enjoy this simple physics demo:

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