Reflection and Refraction
Surfaces Change Light
Reflectivity and refraction of light can be observed and easily created. Light strikes many different surfaces as it travels. Mirrors have the ability reflect light, while liquid and transparent objects have the ability to diffuse and distort waves of light. Light travels slower through liquid than air, which distorts the size and distance of objects when viewed from above the liquid's surface. Light passing through a prism or crystal will diffuse the rays of light into the visible spectrum of colors, and the moon reflects sunlight during nighttime.
Prisms & Crystal Refraction
Light will diffuse into all the colors of the visible spectrum when passing through a prism or crystal. Light contains the entire visible color spectrum, and each individual color has different wavelengths. Each color separates when exiting the prism. The visible color spectrum contains violet, indigo, blue, green, yellow, orange and red. Bright colors like orange and yellow have high wavelengths, while darker colors like indigo have lower wavelengths. Raindrops act like mini prisms to create rainbows during a light rain.
Mirrors reflect nearly all light due to their flat surface and highly reflective properties of the metal behind the glass. Traditionally, silver was used as the reflective surface behind the pane of glass. Angling a mirror into sunlight will create a bright spot on surroundings. The bright spot is the reflection of the Sun off the mirror. Simply staring at the Sun's reflection long enough can cause blindness. A reflective non-uniform surface will reflect light in many directions. A disco ball, broken glass and crinkled aluminum foil are some examples. Reflective road signs feature an adhesive backed material that is superb in reflecting light in many directions.
Putting a spoon into a clear glass half full of water demonstrates the refraction of light as it passes through the glass of water. The spoon will appear broken in half when viewed through the glass. There are a few reasons why this occurs. Light travels 25 percent slower in water compared to the flawless conditions inside a vacuum. Light also bends when it strikes the surface of water and other liquids. Slowing the speed of light distorts the distance and size of objects below the surface of the liquid.
Light refraction is also contributed to the inability of humans to focus eyesight underwater. The cornea of the eye has a density similar to the density of water. The layer of water refracts the light once, while the eye bends the light again. This multiple bending of light before it reaches the cornea is what makes underwater vision blurry.
The moon emits a subtle glow during post-sunset. The Moon appears to produce its own glow, but this occurs because of the Sun. During times of darkness, the Moon is reflecting the Sun's rays. The Moon orbits the Earth and the Earth orbits the Sun. The moon appears to regions experiencing nighttime hours when Earth is between the Sun and Moon. This alignment is suitable for sunlight to reflect off the Moon, and towards Earth.