Who invented the first microscope?

One of the first microscopes. Image source: http://www.dipity.com

In the late sixteenth century, two Dutch eyeglass makers discovered that objects appear magnified when viewed through multiple convex lenses in a tube. For this simple discovery, Hans Janssen and his son Zaccharias are considered by some to have invented the microscope around 1590. About this same time, another eyeglass maker from Holland, Hans Lippershey came up with the same idea and is also considered by some to be one of the inventors.

“The coining of the name “microscope” has been credited to Giovanni Faber, who gave that name to Galileo Galilei’s compound microscope in 1625. [wikipedia]

Anton van Leeuwenhoek (1632-1723) is really considered to be the “father of microscopy” when he worked as an apprentice in a dry goods store where magnifying glasses were used to count the threads in cloth. He taught himself new methods for grinding and polishing lenses of great curvature which gave magnifications up to 270 times, the greatest known in that day. These led to the building of his microscopes and the biological discoveries for which he is famous. He was the first to see and describe bacteria, yeast plants, the teeming life in a drop of water, and the circulation of blood corpuscles in capillaries. During a long life he used his lenses to make pioneer studies on an extraordinary variety of things, both living and non living, and reported his findings in over a hundred letters to the Royal Society of England and the French Academy. [source about.com]

How can I make slime?

My son and me making slime

Every few months or so, my son and I like to make straight-chain polymers out of of polyvinyl acrylic (PVA) and sodium tetraborate. It’s pretty simple to do. You just mix one part PVA with one part dihydrogen oxide. Then make a solution of about 40 mg of Na2B4O7, and 400 cc of more dihydrogen oxide. Then slowly mix this solution into the PVA mixture. Of course, we add a little food coloring for effect. The result is this great fun-to-play-with polymer!

Okay, so Polyvinyl acrylic is just Elmer’s glue. Sodium Tetraborate is household Borax. And dihydrogen oxide is water. And our polymer is more commonly called slime. I figure it’s never too early to start teaching my son the chemistry behind what we we’re doing. In a nutshell, making your own slime is easy. Here are the steps summarized:

1. Pour a bottle of Elmer’s Glue in a bowl. Add the same amount of water. Stir.
2. Put about the same amount of water in another bowl and add a couple tablespoons of Borax. Stir.
3. Add this Borax solution to the glue mixture a little at a time while stirring.

It doesn’t take much to make a nice slimy polymer. Experiment with the volumes and you’ll see how easy it is.

What animal has the longest gestation period?

You might think the animal with the longest gestation period would be one of the larger mammals, but in fact it is the Alpine black salamander. It is a viviparous amphibian which lives in the high altitude Swiss Alps. At altitudes above 4,600 feet, it’s gestation period can be up to 38 months. It bears two fully metamorphosed young.

Who discovered the atom?

By most standards, John Dalton is credited with having been the first to propose (and somewhat prove) that all matter was made of atoms. He did this in the early 1800s in his experiments calculating the atomic weights of gaseous elements. Isaac Newton also proposed such a theory in the 1600s although the technology in his time didn’t allow him to experimentally prove his theory. Even before Newton was the ancient Greek philosopher Democritus who had a similar proposal.

The first scientist to significantly “prove” the existence of atoms was Rutherford who “invented the cloud chamber and used it to show that when thin gold foil is bombarded by helium nuclei (alpha particles), the particles are occasionally deflected by a very large angle, but usually pass straight through. This gave rise to the realization that the gold was composed of atoms, with a tiny nucleus at the middle which could occasionally collide with an alpha particle and send it flying.” [source: newton.dep.anl.gov]

What the heck is a pedicar?

Image source: http://asyl.ucoz.com

The pedicar was a pedal-powered, all-weather one passenger vehicle introduced in 1973 as a response to the energy crisis of the mid-1970s. According to the Handy Science Answer Book, it had straight-line pedal action, disc brakes, five forward speeds, neutral AND reverse. It’s 1973 cost was about $550 (US) which was fairly expensive as you could have bought a new Volkswagen beetle for at the time for about $1,300, and a used one for less than the cost of the pedicar.

The pedicar was conceived to be an alternative to the automobile. Claims of its speed were between 8 and 15 mph (13-15 k/h). It never quite took off in popularity and ended up mainly being used as a novelty conveyance around parks, resorts, country clubs and some college campuses.

It’s too bad this car didn’t become more popular as I would have enjoyed pedaling this thing to work every day at about 8 mph. Yeah, right.

How can you tell the age of a fish?

Like the rings on the cross section of a tree, fish scales also have rings. Fish scales have concentric ridges called circuli which reflect the growth patterns of the fist and can be used to estimate the age. From “The Handy Science Answer Book,” the portion of the scale that is embedded in the skin contains clusters of these circuli, called annuli. Each of these clusters mark one year of growth.

So what about fish that don’t have scales? Like catfish, dolphins or sharks? I’ve heard that a seasoned biologist (or ichthyologist) could possibly make a fair estimate by looking at their teeth. But I would take this answer with some skepticism and say that this is probably difficult to do.

What is the slowest animal in the world?

Source: http://mindjourney1962.wordpress.com

There are a couple of ways this question can be answered. Sea anemones and sponges are animals and they hardly move at all, so I guess one of these guys could be considered very slow indeed. Clams, oysters and snails are pretty slow as well. But I guess most people asking this question are actually wondering what are the slowest vertebrates.

The winner in this category is most likely the three-toed sloth. It has been said that it would take a sloth about a month to walk a mile, though this is still a bit unfair since sloths really don’t ever walk. They spend their time hanging upside down in trees. They even sleep, eat and have babies while hanging upside down. I imagine they even do what they do to make babies while hanging upside down, but I’ve never personally witnessed sloth copulation. Probably a good thing.