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A Nice Visual Illusion

Phillip Alvelda — Wed, 03 Oct 2007 17:19:00 +0000

No, this one is not animated. All the motion is happening in your head. If you don’t believe me, try covering most of the image with your hand or a piece of paper and only looking at a small part. You will see that no individual part of the image moves at all. It is only when you try to see the whole image that you notice motion.

So can any of you tell me how this works?

A Great Spinning Optical Illusion

Phillip Alvelda — Wed, 27 Jun 2007 08:45:00 +0000

If you look at the spinning girl’s silhouette below, you will think it is spinning clockwise, probably. When you check her shadow below, momentarily the spinning direction changes in your mind, and now the girl is spinning counter-clockwise. It can be quite hard at the beginning to notice switch of the spinning direction, but eventually you’ll manage.

Atmospheric Optics

Phillip Alvelda — Fri, 01 Dec 2006 12:27:00 +0000

I stumbled upon a very cool site this morning from the UK called Atmospheric Optics. The site is comprised of an extensive series of images and explanations (some of the best I have ever seen) for the most common optical phenomena that result from various atmospheric conditions.

Rainbows, halos, shadows, ice crystals, and sunsets all figure prominently. Do check it out if you have even a passing interest in physics or even if you just like pretty sunsets. Here’s a sample on the directory page for the Rainbow Section.