First, how do we define direct and indirect light? If I'm standing out in the yard and the sun is shining down directly on me, that is direct sunlight. If I am on my front porch and the sun doesn't shine on me but rather the light reflects upon me, that is indirect sunlight. How does this definition work for the seasons? Hm, the above definition isn't the best for defining direct and indirect sunlight on earth.... How about this one: Direct Sunlight (heat energy) - Covers a small surface area; heat is concentrated and warmer; Sun is high in the sky; summer heat energy is direct. Indirect Sunlight (heat energy) - Covers a large surface area; heat is spread out and colder; Sun is low in the sky; winter heat energy is indirect. Can we feel direct and indirect light? Well! I just happened upon some experiments were done on people to test their behavior in direct and indirect light. The data showed that people exposed to direct outside light worked harder and were more productive. People exposed to artificial light or dimmed light became sleepy and were not very productive. (https://blog.bufferapp.com/the-science-of-how-room-temperature-and-lighting-affects-our-productivity) The tilt of the Earth affects the length of days and also the amount of direct sunlight received during the seasons. We have learned that days are shorter in the Northern Hemisphere during the winter because the North Pole is tilted away from the sun and the Northern Hemisphere receives less direct sunlight. Just the opposite is true in the summer, when the North Pole is tilted toward the sun. As the Earth orbits the sun, the Northern and Southern Hemispheres are put into and out of direct sunlight. The part of the Earth tilted toward the sun gets more direct sunlight than the part tilted away from the sun. In equatorial regions, the length of days and the directness of sunlight don't change as much. This is why the four seasons of winter, spring, summer, and fall don't occur there. Now we know if you hate the seasons there is someplace to go! The area near the equator. The above diagram shows the warmest areas in red. The blue areas are the coldest. This is a colorful snapshot of what the earth looks like under direct and indirect light. Astronomers are learning more and more every year how direct and indirect light effects our planet. Our size and relationship to the sun is very unique and complex. By the time your grandchildren are learning about the seasons, their story may be very different from the story you have learned. That's why science is so cool!
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Mrs. TaylorI love science! Everything about the world is interesting and never boring. I love to study plants, animals, insects, and people. My favorite subjects are my students who are the most unique organisms on the planet! Categories |