- The moon weighs 81 billion tons. - When the moon is directly over your head, you weigh slightly less. - It takes about 1.25 seconds for moonlight to reach the Earth.
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DNA (deoxyribonucleic acid) was first discovered by Friedrich Mieschler of Switzerland in 1869. It is a very important molecule found in all living cells. It is the main genetic material in all living organisms. It contains information used in everyday me
Lightning bugs (or fireflies) glow in the dark. But why do they flash? They do this to find mates. The females flash at flying males. Then the males flash back and try to find females of the right species. A short flash dialogue takes place as the male fl
Comets are made out of dust and ice. They are like a dirty snow ball! Scientists sometimes call them planetesimals. These icy comets orbit the Sun in two different places. One place is called the Oort cloud, and the other is called the Kuiper Belt.
Acid rain is a result of air pollution. Lots of different chemicals are produced whenever any type of fuel is burnt. Cars, factories and power stations all burn fuels. And they all produce polluting gases. Some of these gases react with the small droplets
At the very edge of the visible universe, scientists can see very bright and powerful objects called “quasars.” Quasars are about the size of the Solar System. They produce more light and energy than 1,000 galaxies!
Thunder is the sudden loud noise which comes from the sky during a thunder storm. A thunder storm is a storm that makes lightning and thunder. Thunder storms can also produce flash floods, hail, strong winds, and even tornadoes.
The brain is a complex organ. It consists of gray matter (40%) and white matter (60%). The brain has three main parts: the cerebrum대뇌, the cerebellum소뇌, and the brain stem. The average weight of an adult human brain is about 1.3-1.4 kilograms. At bi
Red blood cells are sometimes simply called “red cells.” They are doing a very important job in your body. They travel through your body continuously, delivering oxygen and removing waste. A single drop of blood contains millions of red blood cells! Red
The sea appears to be blue most of the time. But the sea can be many other colors depending on particles in the water, the depth of the water, and the amount of skylight. The colors we see depend on the reflection of the visible wavelengths of light to ou
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