Anatomy of an Egg - Exploratorium
网页Bumpy and grainy in texture, an eggshell is covered with as many as 17,000 tiny pores. Eggshell is made almost entirely of calcium carbonate (CaCO 3 ) crystals. It is a semipermeable membrane, which means that air and moisture can pass through its pores. The shell also has a thin outermost coating called the bloom or cuticle that helps keep out ...
A Brief History of Pi (π) - Exploratorium
网页Here’s a brief history of finding π. The ancient Babylonians calculated the area of a circle by taking 3 times the square of its radius, which gave a value of pi = 3. One Babylonian tablet (ca. 1900–1680 BC) indicates a value of 3.125 for π, which is a closer approximation. The Rhind Papyrus (ca.1650 BC) gives us insight into the ...
Your Weight on Other Worlds - Exploratorium
网页Scales measure the force of attraction between you and the Earth. This force of attraction between you and the Earth (or any other planet) is called your weight. If you are in a spaceship far between the stars and you put a scale underneath you, the scale would read zero. Your weight is zero. You are weightless.
What Causes a Solar Eclipse? | Exploratorium
网页A solar eclipse occurs when the moon passes between the Sun and Earth, casting the moon's shadow on Earth. This only happens occasionally, because the moon doesn't orbit in the exact same plane as the Sun and Earth do. Two things need to occur at once for you to see a solar eclipse: the Sun, moon, and Earth need to be in a straight line, with ...
Origins: CERN: Ideas: The Big Bang - Exploratorium
网页The universe began, scientists believe, with every speck of its energy jammed into a very tiny point. This extremely dense point exploded with unimaginable force, creating matter and propelling it outward to make the billions of galaxies of our vast universe. Astrophysicists dubbed this titanic explosion the Big Bang.
Your Age on Other Worlds | Exploratorium
网页To Do and Notice. Fill in your birthdate below in the space indicated. (Note you must enter the year as a 4-digit number!) Click on the "Calculate" button. Notice that your age on other worlds will automatically fill in. Notice that Your age is different on the different worlds. Notice that your age in "days" varies wildly.
Build a Solar System Model | Exploratorium
网页If you build your solar system on a roll of toilet paper, you can make the Sun about .4 inches (10 mm) across and still fit the entire solar system on the roll. A standard roll of toilet paper has about 450 sheets that are about 4.375 inches long, hence the roll is about 164 feet long. You should check your toilet paper for length.
Secret Language: Cryptography & Secret Codes | Exploratorium
网页The algorithm or method used to encipher the original message (known as the plaintext). The key used with the algorithm to allow the plaintext to be both enciphered and deciphered. The period or time during which the key is valid. By way of analogy, to get into your home you would put a key in a lock to open the door.
Science of Bread: Bread Science 101 - Exploratorium
网页This organism lies dormant until it comes into contact with warm water. Once reactivated, yeast begins feeding on the sugars in flour, and releases the carbon dioxide that makes bread rise (although at a much slower rate than baking powder or soda). Yeast also adds many of the distinctive flavors and aromas we associate with bread.
How to View a Solar Eclipse | Exploratorium
网页2. Cut a one-inch hole in the center of one end of the box. Tape a piece of foil over the hole, then poke a small hole in the foil with a pin. 3. At the other end of the tube, cut a good-sized viewing hole in the side of the box. Put a piece of white paper at the end of the box, right inside the viewing hole.