Electricity
Electric currentthe electrons crawl, your lamp is on at once6:12
Voltage and capacitytwo batteries, the same number4:43
Connecting ammeter and voltmeterswapping them wrecks your meter4:10
Direct and alternating voltage and the diodewhy does an LED only work one way?4:11
Resistance and Ohm's lawdoes resistance double with voltage?4:21
Resistance of a wirewhy a long cable charges slowly4:40
Variable resistor, NTC, PTC and LDRresistors that change by themselves3:40
Series circuitwhich lamp gets the most current?3:32
Parallel circuitwhy does the resistance actually get smaller?3:56
Series-parallel circuitwhy adding up doesn't work here3:37
Circuits practical testhow to find the resistor under the tape5:13
Powerwhy is there no such thing as watts per hour?2:58
Kilowatt-hourwhat does your wifi router cost per year?3:05
Efficiencywhere does the rest of the energy go?3:43
Earthing and residual current devicewhat protects you from a shock?2:58
About me

My name is Thomas Schuurmans, and I have a passion for physics and for understanding why things work the way they do. What I want is to get young people asking “why is that?” and “how does that work?” more often, and to hand them the tools of physics in a way that is simple and that you can see.
I graduated in applied physics at Delft University of Technology in 2003. After that I spent more than twenty years outside education: first at TNO, the Dutch applied research institute, then at a design agency, and eventually founding Proportion Global, through which I work on innovation questions in Africa, Latin America and South Asia. That work resembles physics more than you would expect: don't start from a solution, first understand what is going on, try something, be wrong, and look again.
Proportion Global now works with a network of local consultants in 67 countries, so I hardly need to travel myself any more. That gives me more time, and more of a need, to make a difference closer to home as well. So I picked up my old love for physics again. Since September 2026 I have been teaching physics two mornings a week at the Cartesius Lyceum in Amsterdam, to lower and upper secondary classes.
I am very much a visual learner myself when I want to learn something new. That is where the idea came from: videos that explain one topic sharply and visually, in just a few minutes. I make them for my own pupils. Then I publish them, because a good explanation should be within reach of anyone who needs it, wherever you live and whatever language you think and speak in.








