How long is the cable on this crane? #iteachphysics 🎢

Colored shadows! #iteachphysics 🎢

Water reflecting off of lake water is polarized #iteachphysics 🎢

Here's an air capacitor, an air battery (bike pump), and a switch (valve). You can see the capacitor charging and discharging, and most students agree no air passes through the rubber membrane of the air capacitor. #iteachphysics