Have students place the images in the order of brightest to least bright. Discuss with students why they think one particular light source worked better than others.
What's Happening? When light hits normal, everyday objects, it usually is either absorbed or immediately reflected. The color it glows depends on the type of material. Because the light slowly is being released, it appears to glow even after the light source is turned off.
Different types of lights will affect how much energy is able to be stored in a phosphorescent object. Infrared light waves have less energy than ultraviolet light waves. Although incandescent and fluorescent lights both look white, the individual colors in them are different.
Incandescent light bulbs emit visible light with a large percentage of infrared light. Fluorescent lights emit visible light with some ultraviolet light mixed in. The stars that absorbed pure ultraviolet light will be the brightest, since ultraviolet light has the most energy out of all light sources tested. The fluorescent light contains some ultraviolet light, so it will be the second brightest. Are there other types of light waves that also could be tested? Extended Activities and Links Explore fluorescence by examining classroom or household items under a black or ultraviolet light, taking care not to look directly at the light source once it is turned on.
Have students conduct an investigation, based on their observations, to determine the differences between fluorescence and phosphorescence. Two phosphors that have these properties are Zinc Sulfide and Strontium Aluminate.
Strontium Aluminate is newer -- it's what you see in the "super" glow-in-the-dark toys. It has a much longer persistence than Zinc Sulfide does. The phosphor is mixed into a plastic and molded to make most glow-in-the-dark stuff. Occasionally you will see something glowing but it does not need charging. The most common place is on the hands of expensive watches.
In these products, the phosphor is mixed with a radioactive element, and the radioactive emissions see How Nuclear Radiation Works energize the phosphor continuously. In the past, the radioactive element was radium, which has a half-life of years.
Today, most glowing watches use a radioactive isotope of hydrogen called tritium which has a half-life of 12 years or promethium, a man-made radioactive element with a half-life of around three years. Sign up for our Newsletter! Each type of luminescence is created in a different way. Phosphorescence is the kind of luminescence that uses phosphors to make something glow in the dark.
Some examples of this type of luminescence include items like a computer screen and white LED lights. Chemiluminescence makes things glow by creating a chemical reaction.
The electrons within the object become excited because of the reaction between two chemicals, and the electrons give off energy by glowing. Glow sticks are a good example of this process, since they require you to mix the chemicals inside to make the stick light up. You likely won't see many things sold at the store using radioluminescence, but it is another form of luminescence that can cause things to glow.
This type of luminescence refers to items that glow due to nuclear radiation. One of the coolest forms of luminescence is called bioluminescence, which refers to living things that glow in the dark. These creatures have an internal process that causes a chemical reaction and creates a bright light.
While you don't ordinarily see the whiteners, they cause white paper to appear blue under ultraviolet light. Some papers are marked with fluorescent dyes that appear only under certain lighting. Banknotes are a good example. Try looking at one under a fluorescent light or a black light to reveal additional information. Tritium is an isotope of the element hydrogen that emits greenish light.
You'll find tritium in some self-luminous paints and gun sights. Radon is a colorless gas at room temperatures, but it becomes phosphorescent as it is cooled. Radon glows yellow at its freezing point , deepening toward orange-red as the temperature is lowered even further. Coral is a type of animal related to jellyfish. Like jellyfish, many forms of coral either glow on their own or when exposed to ultraviolet light.
Green is the most common glow-in-the-dark color, but red, orange, and other colors are also known to occur. Actively scan device characteristics for identification. Use precise geolocation data. Select personalised content. Create a personalised content profile. Measure ad performance. Select basic ads.
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