Physics Experiments: Hydrodynamic Levitation

A really fun phenomenon that Simon learned from the Veritasium channel, based upon the Coanda effect. Simon later went on to repeat this experiment several times, even in the cold fountain at the park – anything for science!


Physics Experiments: Light and trapped inside the water stream

Another take at our light trapping experiment, this time using a red laser pointer. We punched a hole in the plastic bottle and filled the bottle with water. As the water flows through the hole, the trick is to point directly at the hole through the bottle. This makes the photons enter the water stream and they can no longer leave it, getting reflected inside the stream and traveling along with it, so no longer in a straight line. This is exactly the way fiber optic cable works.

Simon gave me a whole lecture the other day about how fiber optic cable transmits binary data like a morse code, with long light flashes for ones and short flashes for zeros. (“And underwater robots fix them!”) He explained ASCII, the way to encode English letters and special characters in binary, 95 characters in total: “7 bits allowing for 128 combinations, which is even an overkill. To transfer pixels, you need 24 bits. And 2 to the 24 is exactly the same as 256 to the third (total number of possible shades). I worked this out!”

With two bottles:

Physics Experiments: Standing wave

“It’s so mesmerising!” Simon explains what a standing wave is and the nodes in a wave, using a Slinky. Standing waves can be polarised in any direction (horizontally, vertically or diagonally) or they can be circularly/elliptically polarised or any combination of polarisation direction. A sea wave is normally just a regular wave, but it can become a standing wave if you introduce some kind of boundary.


Physics Experiments: The Color Wheel and Mind Blending

Inspired by Physics Girl, here come a couple crafty color wheel experiments involving what Physics Girl calls “mind blending” (it may not be the real name) – mixing color wave lengths in your mind. Simon has already studied the way our brain perceives blended/ moving color before, in the several optical illusions he programmed. This time, however, he decided to observe how simple paint can produce the same effect.

CORRECTION by Simon: You can’t actually even see the entire visible spectrum. You only see red, green and blue (I couldn’t think of that in the video).

The rotating green and red disk look more yellow in this extra 2 sec of footage taken by a different camera:

Simon prepared the props himself, with some help from his sister New (who painted one of the disks) and me (I helped cutting the hard cardboard). We couldn’t figure out a way to get the disks to spin fast and tried several options (like straws, pencils and even a dismantles giroscope). Eventually, we decided to use a small drill from a children’s woodworking set and it worked!

Making the fourth disk was the most difficult part as Simon wanted to divide the circle into 12 equal sectors. He came up with this elegant solution: he drew a hexagon and then bisected every angle (see below).

Simon made his own foam Rubik’s Cube

Simon saw this design in a video by Mathologer and adapted it slightly (Mathologer used glue and no screws). He had dreamt of making a cube like this for months, but the idea of crafting one from wood seemed too complicated. Today it occurred to him that he can make the design using his new woodlike foam and press iron screws into the foam to hold the magnets! On to the wooden model now!

The Standard Model

Simon, let’s go to the beach, let’s get your shoes on! What’s that on your foot? – Oh, I was just building the Standard Model of Elementary Particles.

Simon is very fond of the new Physics book we are reading before bedtime, it’s called We Have No Idea and it’s about everything yet to be discovered.

Experimenting with electromagnetism

Here Simon tried to induce a magnetic field by allowing electric current to go through a conductor that is normally not magnetic (copper wire). The green stick is a magnet that got attracted to it once the circuit closed.

The copper wire also began to slightly attract the steel paperclips.

The Leaning Tower of Lire

Also known as the Book-Stacking Problem. Simon had tried to build this tower at the Fries Museum where we visited a huge Escher exhibition (to the annoyance of the museum staff, to whom I had to explain that it was a serious math experiment and not just a kid dropping bricks), but it only worked with 4 blocks (possibly because the blocks were made of foam and weren’t rigid enough). He tried to stack the blocks on top of one another, shifting every next block first by one eighth, then by one sixth, next by one fourth, and next by one half – in the end, the top block would no longer be positioned above the bottom block.


He repeated the experiment at home, first doing some calculations and then using more rigid wooden blocks and managed to stack a tower of 6 blocks! (The top block still overlapped the bottom one by a bit though) :