Howstuff works carbon 14 dating
Marina Chicurel - Can Organisms Speed Their Own Evolution?
Over the centuries, our view of light has changed dramatically.If you're behind a web filter, please make sure that the domains *.and *.are unblocked.Fundamental properties of atoms including atomic number and atomic mass.Other Greek philosophers -- most notably Euclid and Ptolemy -- used ray diagrams quite successfully to show how light bounces off a smooth surface or bends as it passes from one transparent medium to another.Arab scholars took these ideas and honed them even further, developing what is now known as geometrical optics -- applying geometrical methods to the optics of lenses, mirrors and prisms. Ibn al-Haytham identified the optical components of the human eye and correctly described vision as a process involving light rays bouncing from an object to a person's eye.Scientists know how quickly radioactive isotopes decay into other elements over thousands, millions and even billions of years.
Scientists calculate ages by measuring how much of the isotope remains in the substance.
A half-life measures the time it takes for one half of a radio isotope's atoms to break down into another element.
For instance, if an object has 50 percent of its decay product, it has been through one half-life.
A popular way to determine the ages of biological substances no more than 50,000 years old is to measure the decay of carbon-14 into nitrogen-14.
This process begins as soon as a living thing dies and is unable to produce more carbon-14.
It's in your body, the food you eat and the beverages you drink.