I’ve looked at a number of the Planck units, comparing them to other things, and it was lots of fun, but now I want to now look at where these units come from and how they came to be derived. Let’s find out more. This is going to be a very maths-ey video, and because I always wanted to make videos accessible to everyone I’m going to spend the first part of the video explaining some of the mathematical conventions that I will be using. Ok so let us think about why we have the need for the Planck units. Well let us think about time, the SI unit of time is the second, but humans came up with the concept of the second, it was historically measured as a fraction of a day on this planet, and even though we’ve now redefined it to a great degree of accuracy, it is still related to that ancient measurement. The same goes for all our measurements of length, temperature and mass. Wouldn’t it be great if we could find some way of defining these measurements that isn’t reliant on human made values. This would then transcend our human values. So can we define length, time, temperature and mass just in terms of universal constants. Chapters 0:00 Introduction 0:34 Idea 1 – Units 1:35 Idea 2 – Indices 2:16 Idea 3 – Fractions as Indices 2:38 Idea 4 – Negative Indices 3:48 Idea 5 – Multiplying Indices 4:22 Why do we need them? 5:12 Fundamental Constants 7:18 h bar the Reduced Planck Constant 9:04 G the Gravitational Constant 9:28 c the speed of Light 9:48 kB the Boltzmann Constants 11:04 The Planck Length 15:36 The Planck Mass 18:06 Planck Time 19:56 Planck Temperature