In the process of crystallization, if crystals do not form upon cooling the solution, it is often recommended that the inside of the flask be scratched at the air-liquid interface with a glass stirring rod. What purpose does this serve, and how does it work

What does the process of natural selection involve

Over the last 90 years, scientists have added to the body of evidence supporting the big bang theory. what is the latest piece of evidence discovered in 2014?

If you chip a tooth, most likely you will go to the dentist to have the missing material filled in. currently the material used to fill in teeth is a polymer that is flexible when put in, yet is hardened to the strength of a tooth after irradiation with blue light at a wavelength of 461 nm. what is the energy in joules for a photon of light at this wavelength?