Interesting experiment to investigate sound from clapping hands

 This is an interesting study into the sound created when we clap our hands. And what's more, this is a potential project setup for research of your own. The technique used was filming the patterns of air coming out from one's clapping hands by using baby powder. If you have access to any level of high-speed video tools, you could study these patterns, and compare them between various shaped objects coming together in a clapping manner. Investigate similarities and differences as functions of shape, size, mass, size of the cavities formed when the two objects come together, and anything else you can think of! If you have 3-D printers, you can design different shaped objects and cavities, and so on. 

Here's a brief video of this technique. 

Interesting binary star simulator, showing eclipsing data

 This looks like a pretty interesting binary star system simulator, with the added twist that it shows the eclipsing consequences of the radiation flux we observe from earth. 

If we see a system more from a side view of the plane the star's orbits are on, at certain times one of the stars blocks or partially blocks the other, resulting in dips in the light intensity we detect. This is a great way to measure the orbital periods, which are also needed to determine the masses of the stars. Pretty cool! 

                                                             From Tychos.info

South Atlantic Magnetic Anomaly being watched

 The Earth's magnetic field is quite complex, and includes global reversals where the north and south magnetic poles flip-flop. While scientists have studied it for centuries, the complexity still holds mysteries about the magnetic field. 

The first thing to note is all magnetism we know of comes from moving electric charges and electric currents. For something like a planet, the question then becomes where are the currents? 

The Earth has a solid inner core, but then a molten iron outer core - that is the key. As my students are well aware, metals are special because they have free electrons moving throughout (the 'electron sea'). Normally these free electrons are moving randomly through the metal. But then, we need to remember that the earth rotates. The rotation causes the molten iron to flow in one direction, and suddenly we have a circular current of electrons, and this contributes to the magnetic field. 

Fluid dynamics is complex and very challenging mathematically. Turbulence happens, and because Earth is spherical, that geometry introduces different rotational velocities in different regions of the molten iron. The complexities of flow and the electric currents that result causes the Earth's magnetic field to be dynamic - it is constantly changing, and on occasion when turbulent regions develop, and sometimes the flow locally can be opposite the main flow, irregularities exist within the global magnetic field. This is likely what is happening in the outer core to cause the South Atlantic Magnetic Anomaly. It has grown over the past few decades, and is a region where the magnetic field has already 'flipped' polarity. At some point, perhaps in the coming centuries, the global field may undergo another reversal, where our compass needles will point opposite where it points today. We'll see how this plays out! 

In science, nature always is harder and more complex than what our textbooks tell us, so there are always magnificent mysteries waiting to be solved! Have some fun and take on one of those mysteries that fascinates you!

                                       From Science Alert, 1/29/25