How Do We Define the Kilogram?

The kilogram used to be measured against an agreed-upon chunk of metal stored in France, but no longer. Learn the new measure of this standard unit of measurement in today's episode of BrainStuff.Learn more about advertising on the HowStuffWorks podcasts at www.howstuffworks.com/advertisers.htmAnd to learn about your ad choices when listening to podcasts, visit https://www.howstuffworks.com/privacy.htm#ad-choices