I learned this today. Plants are green because they absorb light in the wavelengths that are red and blue, while reflecting light in the wavelength that is green. Plants create energy through the process of photosynthesis. They convert light energy into chemical energy. Living organisms that convert light into energy are called autotrophs (photoautotrophs to […]
#200 Why are plants green? Read More »
I learned this today. The 1815 Mt. Tambora eruption lowered global temperatures and caused the Year Without a Summer. Mt. Tambora is a volcano on the island of Sumbawa, which is in Indonesia these days. At the time of the eruption, the islands were controlled by the Dutch. The eruption reshaped the island and decimated
#199 What effect did the 1815 Mt. Tambora eruption have? Read More »
I learned this today. The sun flips its magnetic field and its north south poles once every 11 years because its inner dynamo reorganizes itself. How does the sun get its magnetic field? The sun is made of hydrogen and helium gas. Inside the sun, the immense pressure turns that gas into a plasma. Plasma
#198 Why do the sun’s poles flip every 11 years? Read More »
I learned this today. Jupiter’s Great Red Spot is a high-pressure region in the atmosphere that causes the largest anticyclonic storm in the Solar System. An anticyclonic storm is a weather system with very high pressure in the center. The air around the high-pressure center circulates clockwise in the northern hemisphere and anticlockwise in the
#197 What is Jupiter’s Great Red Spot? Read More »
I learned this today. The CIA was formed on September 18th, 1947. The idea behind some kind of agency to manage intelligence seems to have started after the Japanese attack on Pearl Harbor. America was caught unawares by the attack and a lot of people said that they should have had some idea. At the
#196 When did the CIA start? Read More »
I learned this today. A fiber optic cable works by sending information encoded in a beam of light. Different technologies send information in different ways. A telegraph and an old style telephone send signals with electric currents. A cell phone uses radio waves. A fiber optic cable sends signals using light. Fiber optic cables were
#195 How do fiber optic cables work? Read More »
I learned this today. Paper tissues have been used for 1500 years in China, but the modern tissue was invented in 1924. Paper was invented in China in about 100 BC. A government official called Ts’ai Lun is credited as the person who started the paper-making industry. His paper was made by mixing finely chopped
#194 When did people start using tissues? Read More »
I learned this today. Glass and metal can be recycled indefinitely, but plastic can only be recycled once or twice and paper about 7 times. Recycling has been around for as long as people have used resources. There is archaeological evidence of scrap bronze being collected and melted down again in Europe. In 1031, a
#193 How many times can you recycle something? Read More »
I learned this today. A pearl forms in the shell of a mollusk when an irritant becomes trapped there and the mollusk covers it with a fluid that hardens. There are three different types of pearl. There are natural pearls, cultured pearls, and imitation pearls. I am not going to look at imitation pearls. Natural
#192 How does a pearl form? Read More »
I learned this today. Maslow’s hierarchy of needs is a universal classification system which has the most important needs at the bottom and then the following needs in an ascending order of importance. Maslow was an American psychologist. He worked from the early 1930s until his death in 1970. He published his hierarchy of needs
#191 What is Maslow’s Hierarchy of Needs? Read More »
