CAS AS 101 Lecture Notes - Lecture 5: Evaporation, Photon

• School: Boston University
• Department: Astronomy
• Course: CAS AS 101
• Professor: Catherine Espaillat

Document Summary

White light is made up of many different colors. Mirror reflects light in a particular direction. Movie screens scatters light in all directions. Interactions between light and matter determine the appearance of everything around us. Light can either act like a wave or like a particle. Wavelength is the distance between two wave peaks. Frequency is the number of times per second that a wave vibrates up and down. Wave speed = wavelength x frequency = speed of light (constant) Each photon has a wavelength and a frequency. The energy of a photon depends on its frequency. Matter is made up of molecules which consist of two or more atoms. Ionization: stripping of electrons, changing atoms into plasma. Evaporation: breaking of flexible chemical bonds, changing liquid into gas. Melting: breaking of rigid chemical bonds, changing solid into liquid. Phase of a substance depends on both temperature and pressure. Often more than one phase is present.