Happy Summer Solstice

How would you like to watch the summer solstice sunrise or sunset at Stonehenge?

The solstices are the two days when the sun is the furthest north or south from the celestial equator. The full path that the sun takes over the year is the analemma. The solstices are the furthest north and south points on the analemma.

Stonehenge is one of the most well known monuments. The ring of standing stones was built between 3000 BCE and 2000 BCE. This English Heritage website is doing/has done livestreams of sunrise and sunset from the site.

Scientists view atomic bonds breaking and forming

Scientists in the UK and Germany have viewed individual metal atoms making and breaking bonds. They used carbon nanotubes as a scaffold to hold the atoms in place. This is with individual rhenium atoms. You can see the distance between the atoms grow and shrink depending on the environment. It looks like this type of microscopy will become important in chemistry.

Which falls faster, feathers or a bowling ball?

Of course, here on Earth, it’s the bowling ball. But why?

The answer is air resistance. Those darn air particles slow down the low mass feathers. They try to slow down the high mass bowling ball, but have little effect. So the feathers take longer to fall.

But what if you could remove those pesky air particles? Well, they did this on one of the later Apollo missions, but you can also do this on Earth. If you have the right equipment. Fortunately, NASA does.

Which way is down?

This seems like a very simple question. But as this video from vsauce shows, it’s anything but. This goes into things way past my middle school classroom, including general relativity, spacetime, and geodesics. Things are simplified in middle school, and it’s still a difficult thing for kids to get. More below the video.

In middle school we’re more interested in the Newtonian view rather than the spacetime view. For us, down is towards the center of the Earth. It’s the same for people on the other side of the Earth (say in Australia (I’m in New Jersey, USA)). For them, down is still towards the center of the Earth, but that’s in a different direction. My down and their down point in close to opposite directions. That’s because the concept of “down” is a local direction, not a universal one. My down is different from the down of my friend who lives in New Zeeland. This can be a difficult thing for 13 year olds to understand. It helps to show it on a globe, with little stick figures drawn on a folded up sticky notes.