Energy Matters

This week, I have an important task to teach my son and his best friend (both are 10 years old) to differentiate the concepts of Energy and Power. After two hours - I realized how difficult it is to explain the concepts clearly to them. They seem to vaguely understand what it means to be "Powerful" and "Energetic", nevertheless, both have trouble differentiating the two.  I kept saying Power (W) equals to Energy (Ws a.k.a. Watt Second) divided by Time (s) - but neither kids have learnt algebra ! So I said "A sprinter runs 100m with a lot of power in 10 seconds, a marathon runner runs 42km with much lower power in 2.5 hours, even though the sprinter is "powerful" the marathon runner needs much more energy to finish the trip." Finally the two adorable boys nodded their heads and smiled. We scientists and engineers invented so many different units that most of the populations do not use - Wh = 3600 Ws = 3600 J , do you know that in USA, average ho...

Last week, my student who works on solid state batteries made a simple analysis that taught me something important. Professor, did you realize that the raw materials used in batteries have been on steady rise for the last decade? (yes, but one should not use the lithium metal price, but lithium carbonate or lithium hydroxide price) The scientists and engineers were able to improved the technology so much (including replacing Co with Ni, reducing manufacturing process cost etc.) , that the $$/Wh number has been steadily decreasing in the past decade. So true. It is so important to realize that technology can change economics and vice versa. Two important things to know - 1) There is more lithium than lead on the planet earth (of course the lithium in the ocean is hard to get), 2) Price can change with time, demand, supply and many other reasons (and we the scientists should pretend that we know everything)  Side note - There are three things in my career I truly value: (...

                                    The original sense was ‘metal articles wrought by hammering’, later ‘a number of pieces of artillery used together’, whence ‘a number of Leyden jars connected up so as to discharge simultaneously’ (mid 18th century), giving rise to battery. Benjamin Franklin was the first person who used the word battery to describe a set of linked capacitors he used for his experiments with electricity. Electricity - is forever changed with the invention of new batteries. Batteries enable humankind to store, transport and use electricity at demand, any time, any where. Without the storage solution, electrons MUST be consumed when they are generated (of course if we have superconducting device at room temperature, we can store electrons there, but at this time, we do not). If you pay close attention to the history of battery - their progress and development coincides with...