A playground ball finds stability in a saddle when the saddle is rotating at the proper speed.
Mechanical analog of a “Paul Trap” particle confinement—a ball is trapped in a time-varying quadrupole gravitational potential. A large saddle shape (attached to a plywood disk) is mounted on a multi-purpose turntable. The saddle shape is essentially a quadrupole gravitational potential. Rotation of this potential subjects the ball to an alternating repulsive and attractive potential, much like the time-varying electric quadrupole potential of a Paul Trap used in trapping single ions or electrons.
The plastic ball used here is about 25 cm in diameter and was purchased at a toy store. The saddle consists of many layers of fiberglass and was hand-made with help from Justin Georgi. The turntable is driven at about 110 rpm with a DC motor. We have observed this ball at this speed remaining stable for over 2 hours.
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Wired Science has an incredible gallery of the Best Microscope Videos of 2012, via Nikon’s video competition. We have a few favorites: This is a Bay Scallop Argopecten irradians. (Those blue things are tiny eyes.) And here’s a beating heart display of a Danio rerio (zebrafish).
The above video shows a Limnias melicerta (a rotifer) at 200x:
This microanimal lives in a self-built tube attached to waterplants. We see the rotifer using fast moving cilia to create a vortex. This enables it to sweep in food particles like algae. Inside the organism we can also see a jaw-like structures that grind the food.
A women walks in the Musée du Louvre, alone. The museum is completely empty. We follow this young woman in her dreamlike journey through the different rooms of the museum, between amazement and beauty, art and poetry.
Further Up Yonder: A Message From ISS To All Humankind by film student Giacomo Sardelli, using images and audio messages courtesy of NASA. The video’s transcript:
As the most forward deployed citizens of the planet at this moment, and the first expedition crew aboard Space Station Alpha, we are well started on our journey of exploration and discovery, building a foothold for men and women who will voyage and live in places far away from our home planet. We are opening a gateway to space for all humankind.
As we orbit the planet every 90 minutes, we see a world without borders and send our wish that all nations will work towards peace and harmony. Our world has changed dramatically, still the ISS is the physical proof that nations can work together in harmony and should promote peace and global cooperation, and rich goals that are simply out of this world.
On this night, we would like to share with all, our good fortune on this space adventure, our wonder and excitement as we gaze on the Earth’s splendor, and our strong sense that the human spirit to do, to explore, to discover has no limit.
Times are hard all over the world, but this is a time when we can all think about being together and treasuring our planet, and we have a pretty nice view of it up here.