If there is one thing that accompanies each and every one of us everyone of us every time we step out in the day time, it is our shadows. While shadows are easily observed in the daytime, they can be even when it gets dark. If a light source is available.
Shadow, as you would have learnt, are dark areas created when light from a source has been blocked by an opaque (solid) object. As our body blocks some of the sun’s light when we are out and about, it creates shadows as the lights can’t shine through our bodies.
The long and short of it
The length of our shadows changes as the sun rises and sets. While it is bigger and longer when the sun is near the horizon (as we block more light), it is much smaller when the sun is shining from high above us. Have you, however, ever wondered if our shadows can completely disappear?
While they do disappear when there is no light source, there is a special case that will be of interest. In this case, our shadows vanish, even when the sun is still shining. This is popularly referred to as zero shadow day.
Zero shadow days
A zero shadow is an astronomical event that takes place when the sun is exactly overhead, or at zenith, to a specific location. At noon on such days, no object will have a shadow as the sun rays hit the surface perpendicularly.
Zero shadow day occurs twice each year for given place, but not in all locations. For a place to enjoy zero shadow days, its latitude has to be between the Tropic of Cancer (23.5 degrees north of the equator) and Tropic of Capricorn (23.5 degrees south of the equator).
Differs from place to place
Keep in mind that even within these latitudes, the dates will be different for different regions. There are plenty of sources online to help you figure out when zero shadow days will happen where you live. You can also ask your teachers and family members for help. And when you know the dates, make sure you see you know the dates, make sure you see your shadow disappear if your place experiences the phenomenon!
Picture Credit : Google
