The first videos in January of 2010 were on radioactivity, fission, and fusion. The 500th video completes a series on simple machines. In between, Step by Step Science has explained physics, chemistry and math to students of all ages around the world in short videos that guide them through the concepts, equations and formulas that they need to know to succeed in school.

Here are some of our most popular playlists, with selected videos and user comments.

Optics: Ray Diagrams, Reflection, Refraction, Thin Lens Equation: Topics include reflection, refraction, index of refraction, total internal reflection and the thin lens equation. This is the video series that made me realise it’s best to explain how to solve physics problems in a step by step manner. For lenses and mirrors there are about twenty different ray diagrams that students need to be able to draw. It might sound like a lot, but really they are all drawn the same way. The first ray enters the lens or mirror parallel to the principal axis and exits through the focal point and then the second ray is just the opposite — it enters through the focal point and exits parallel to the principal axis. If you can master those two steps then you are 90% there.

Chemical Reactions and Stoichiometry: Covers the five types of chemical reactions and stoichiometry. The beauty of video is that students can see the wonder of chemical reactions from any place in the world. Each of these videos contains a detailed explanation of the chemical reaction and one or more demonstrations showing the type of reaction taking place. Bringing the chemical reactions to life makes a powerful impression on students.

RC and RL Circuit Analysis: All you need to know about resistors in combination with capacitors and inductors in DC circuits. How to calculate voltage, current, capacitance and inductance. This is a very confusing topic for many students. Therefore, it is important to start at the beginning: What is meant by time equals zero seconds? When is time equal to zero seconds? From there, build up the students’ understanding, one step at a time.

Linear Equations: Step by step approach to writing, graphing and solving linear equations. I made this series a few years ago when I was teaching math to eighth graders. Now they have become some of my most popular videos. I am sure it is because I clearly go through the steps students must execute to solve problems for linear equations. Students want to learn, they just need someone to show them how to do it step by step.

These playlists and videos have one thing in common: they break down problems and concepts into their most basic components and build student understanding through step by step explanations. Nearly all videos are under 15 minutes and fill gaps for students who may have missed class or are missing content from their teachers or textbooks.

Thank you for your support and all the great comments over the past years. I am looking forward to making the next 500 videos! And we will see you in the next video.