Shell. 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.

Learn about the long and rich history of π. Pi (π) has been known for almost 4000 years—but even if we calculated the number of seconds in those 4000 years and calculated π to that number of places, we would still only be approximating its actual value.

Be with an astronomer. Find someone who has a telescope and knows how to use it. You can watch the eclipse with your eclipse glasses, but a telescope—with the proper, safe filter!—will make viewing the eclipse even more amazing. If you don’t have a buddy with a telescope, check at your local library or museum for special events.

Egg proteins change when you heat them, beat them, or mix them with other ingredients. Understanding these changes can help you understand the roles that eggs play in cooking. Proteins are made of long chains of amino acids. The proteins in an egg white are globular proteins, which means that the long protein molecule is twisted and folded and curled up into a …

The Exploratorium is more than a museum—it’s a gateway to exploring science, art, and human perception with every visit. Let your curiosity roam through more than 700 interactive exhibits in six spacious indoor and outdoor galleries.

Download the PDF file containing the cipher wheels.; Copy and cut out the two wheels. Place the smaller wheel on top of the larger wheel and rotate them so your "key letter" on the small wheel is beneath the "A" of the large wheel.

One of the most exciting exercises I ever did as a kid was to make a scale model of the Solar System. Most of the pictures in my books made the distance between planets seem small and easy to travel.

Yeast. Yeast, on the other hand, is a live, single-celled fungus. There are about 160 species of yeast, and many of them live all around us. However, most people are familiar with yeast in its mass-produced form: the beige granules that come in little paper packets.

The fact that sugar solidifies into crystals is extremely important in candy making. There are basically two categories of candies - crystalline (candies which contain crystals in their finished form, such as fudge and fondant), and noncrystalline, or amorphous (candies which do not contain crystals, such as lollipops, taffy, and caramels).

Be with an astronomer. Find someone who has a telescope and knows how to use it. You can watch the eclipse with your eclipse glasses, but a telescope—with the proper, safe filter!—will make viewing the eclipse even more amazing. If you don’t have a buddy with a telescope, check at your local library or museum for special events.