Is light a particle or a wave? Or both? Or neither? Learn how humans have defined light throughout history -- including our best attempts today -- in this 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
