Exercise, Geography, Notes on everyday life, Physics, Together with sis, Trips

Some more London

Taking the Thames Clipper
At London’s olympic pool: Simon and Neva took part in the Ultimate Aquasplash, an inflatable obstacle course for competent swimmers that involved sliding down a 3-meter high slide into deep water – another personal victory
At the Queen Elizabeth Olympic Park
Generating power on a bicycle (you could see how many watt you generate)
At a 3D film for the first time
Back to the Science Museum
Astronomy, Experiments, Geography, history, Milestones, Notes on everyday life, Physics, Space, Together with sis, Trips

We’ve found the real 0° meridian!

And it turned out to be a that little path next to the Royal Observatory in Greenwich, not the Prime Meridian line. The 0° meridian is what the GPS uses for global navigation, the discrepancy results from the fact that the Prime Meridian was originally measured without taking it into consideration that the Earth isn’t a perfect smooth ball (if the measurements are made inside the UK, as it it was originally done, this does’t lead to as much discrepancy as when vaster areas are included).

Simon standing with one foot in the Western hemisphere and the other one in the Eastern hemisphere
The GPS determines the longitude of the Prime Meridian as 0.0015° W
Simon tried to use JS to program his exact coordinates, but that took a bit too long so we switched to the standard Google Maps instead
The Prime Meridian from inside the Royal Observatory building
Looking for the real 0° meridian: this is an open field next to the Royal Observatory. At this point, the SatNav reads 0.0004° W.
And we finally found the 0° meridian! Some 100 meters to the East of the Prime Meridian
The 0° meridian turned out to intersect the highest point on the path behind Simon’s back!
Simon and Neva running about in between the measurements of longitude
Astronomer Royal Edmond Halley’s scale at the Royal Observatory
Halley’s scale is inscribed by hand
Experiments, Group, Milestones, Murderous Maths, Physics, Together with sis, Trips

All Nerds Unite: Simon meets Steve Mould and Matt Parker in London

Hilarious, inspirational and loaded with cosmic coincidences, this was one of the best evenings ever! Many of our currently favourite themes were mentioned in the show (such as the controversy of Francis Galton, the BED/ Banana Equivalent Dose, sound wave visualizations, laser, drawing and playing with ellipses, Euler’s formula). Plus Simon got to meet his teachers from several favourite educational YouTube channels, Numberphile, StandUpMaths and Steve Mould.

With Steve Mould
With Matt Parker
art, Coding, Geometry Joys, Murderous Maths, Museum Time, Notes on everyday life, Together with sis, Trips

Back at Stedelijk

As for Morellet’s RGB colored cells, very inspiring for a sandpiles coding project. (The photographs don’t convey half of the effect the original canvasses invoke. Morellet’s cells actually appear to be moving when you gaze at the original).
Installation by Barbara Kruger
Installation by Barbara Kruger
Read this poem from top to bottom and it’s depressing, from bottom to top and it’s empowering.
Contributing, Milestones, Murderous Maths, Museum Time, Physics, Trips

The Brachistochrone

Simon believes that he has found a mistake in one of the installations at the Technopolis science museum. Or at least that the background description of the exhibit lacks a crucial piece of info. The exhibit that allows to simultaneously roll three equal-weight balls down three differently shaped tracks, with the start and the end at identical height in all the three tracks, supposes that the ball in the steepest track reaches the end the quickest. The explanation on the exhibit says that it is because that ball accelerates the most. Simon has noticed, however, that the middle track highly resembles a cycloid and says a cycloid is known to be the fastest descent, also called the Brachistochrone Curve in mathematics and physics.

In Simon’s own words:

You need the track to be steep, because then it will accelerate more – that’s right. But it also has to be quite a short track, otherwise it takes long to get from A to B – which is not in the explanation. It’s not the steepest track, it’s the balance between the shortest track and the steepest track.

Galileo Galilei thought that it is the arc of a circle. But then, Johan Bernoulli took over, and proved that the cycloid is the fastest.

The (only) most elegant proof I’ve seen so far is in this 3Blue1Brown video: https://www.youtube.com/watch?v=Cld0p3a43fU

There’s also a VSauce1 video, where they made a mechanical version of this (like Technopolis): https://www.youtube.com/watch?v=skvnj67YGmw

Wikipedia Page: https://en.wikipedia.org/wiki/Brachistochrone_curve

We’ve also made some slow motion footage of us using the exhibit (you can see that the cycloid is slightly faster, but as far as I can tell, it’s not precision-made, so it wasn’t the fastest track every time): https://www.youtube.com/watch?v=5Brub0FnpmQ

I hope that you could mention the brachistochrone/ cycloid in your exhibit explanation. I don’t think you can include the proof, because for such a general audience, it can’t fit on a single postcard!

Exercise, Experiments, Notes on everyday life, Physics, Simon teaching, Together with sis, Trips

A lot of fluid dynamics at Technopolis

Today we celebrated my 40th birthday with a family trip to Technopolis, a mekka for science-minded kids in the Belgian town of Mechelen. (Technically, my real birthday is in two days from now, but I have messed with the arrow of time a little, to speed things up).
The entrance to the museum is adorned with a red lever that anyone can use to lift up a car!
Simon and Neva lifting up the car
The beautiful marble run and math and physics demo in one
Galton’s board and Gaussian distribution
Simon explaining the general relativity demo, which is part of the marble run
This was probably the winner among all the exhibits: a wall to climb with a mission (Simon figured it out rather quickly – one had to turn “mirrors” to change the direction of light (green projection) and have the light rays extinguish the targets.
Simon tried to explain this to other children, but they only seemed to want to climb. It was sad to see how no one cared to listen (well, except for Neva of course).
Simon was already familiar with this optical illusion. Later he saw another version of this on an Antwerp facade.
The logic gates were too easy.
the center of gravity
Huge catenaroids! Something Simon had already demonstrated to us at home, but now in XXL!
And huge vortices! Another passion.
Hydrodynamic levitation! Hydrodynamic levitation!
Look! A standing wave!
And another standing wave!

Here Simon explains one more effect he has played with at home, the Magnus effect.

Exercise, Math Riddles, Murderous Maths, Notes on everyday life, Simon teaching, Simon's sketch book, Together with sis, Trips

Math on the Beach

Sunday at the beach, Simon was reenacting the 5 doors and a cat puzzle (he had learned this puzzle from the Mind Your Decisions channel). The puzzle is about guessing behind which door the cat is hiding in as few guesses as possible, while the cat is allowed to move one door further after every wrong guess.

the little houses served as “doors”, and Simon’s little sister Neva as “the cat”

“Here’s a fun fact!” Simon said all of a sudden. “If you add up all the grains of sand on all the beaches all over the world, you are going to get several quintillion sand grains or several times 10^18!” He then proceeded to try to calculate how many sand grains there might be at the beach around us…

In the evening, while having a meal by the sea, Simon challenged Dad with a Brilliant.org problem he particularly liked:

Simon’s explanation sheet (The general formulas are written by Simon, the numbers underneath the table are his Dad’s, who just couldn’t believe Simon’s counterintuitive solution at first and wanted check the concrete sums. He later accepted his defeat):