Get hypnotized by this wave pendulum … seriously, I can’t look away.
A wave pendulum like this is built of equally weighted objects suspended by different (and carefully calculated) lengths of string. Released simultaneously, their differing periods (frequencies of oscillation) cause them to form a “wave” image together that cycles through all possible patterns.
It’s mind-boggling. Looking for a science fair project? This would be a great one.
(via Citadel Physics)
Classical mechanics works!
When you drill 364 meters (1194 feet) down into Antarctic ice, taking out a cylindrical section called an ice core, you can find out about the Earth’s temperature and carbon dioxide levels from over 20,000 years ago. Information is held within the oxygen atoms in the ice and the air bubbles that formed within it.
Measuring ice cores is an effective form of time travel for scientists like the British Antarctic Survey team, who are studying how the Earth’s climate is changing. And Antarctica is full of untapped information:
Antarctica is thought to have been covered by ice for over 30 million years. So far, scientists have drilled ice cores stretching back 800,000 years, and they are now working to extend their records back to 1.4 million years ago.
Metastability: dynamics matters!
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.