May 14, 2010

Happy Birthday, Mikhail Tsvett

This Russian botanist (plant scientist), born on this day in 1872, discovered chromatography. He was trying to separate a mixture of plant pigments that were very similar to each other. One method he tried was trickling the mixture through a glass tube packed with calcium carbonate powder. As the liquid trickled down through the powder, each kind of pigment stuck to the powder with its own unique amount of strength. This created a series of bands (or stripes), and each band was a different pigment.
Using his new technique, Tsvett discovered several new plant pigments. He named the technique chromatography, the resulting bands a chromatograph, and the new pigments carotenoids.
Although Western scientists did not discover Tsvett's work for 30 years, his technique is now used all over the world.

Felt Pen Chromatography

This will work with any water-based felt-tipped pen, but it's most fun to use a bunch of different brands of black markers. (Again, remember, they have to be water-based markers! Don'
Another felt pen chromatography experiment, using blotter paper, is described on the website Dad Can Do. Yes Mag also writes up the experiment (with slightly different instructions—but lots of photos!)

Chalk Chromatography

Test red, yellow, green and blue food coloring to see if they are made of various substances. Instead of using coffee filters or blotter paper, use white chalk. At the end of the experiment, you will have cool-looking chalk with a colorful outer decoration.

Get instructions here.

Leaf Chromatography

Squeeze some “leaf juice” onto the coffee filter to test for pigments in plant leaves. This experiment is more like Tsvett's original research. Get instructions here.

T-Shirt Chromatography
Get an old (or cheap-and-new) white T-shirt for this activity. This time, use alcohol rather than water, and permanent markers rather than water-based ones. Follow the instructions carefully to make a unique Tee to wear.

Did You Know...?

Forensic science (crime-scene investigation) can involve chromatography to see what type of pen was used in a crucial piece of evidence. Unfortunately, the test would tend to destroy the evidence—so I'm sure that CSI scientists test only part of a small part of the message, letter, or other ink sample.

January 9, 2010

Clip art copyrighted by Bobbie Peachey,
http://webclipart.about.com

On this date in 1793, Jean Pierre Blanchard became the first person to successfully fly a balloon in the U.S.

Blanchard was a French man who had already ignited “balloonmania” in Europe with successful flights in his hydrogen gas balloon, starting in 1784 (although other people had already ballooned the year before). Suddenly people wanted to buy things (such as fans and ceramics and hats) decorated with images of balloons; people even wore clothing au ballon, with huge puffed sleeves and rounded skirts, or hair styled au demi-ballon.

By 1793 Blanchard brought his balloon to America. In front of witnesses such as George Washington, John Adams, Thomas Jefferson, James Madison, and James Monroe, he ascended from Philadelphia, Pennsylvania, and landed in New Jersey.

I can't seem to spot who made January 9th “Balloon Ascension Day” in the U.S. (although I ran across a few vague mentions of President Lincoln), or when (again, vague mentions of Civil War times), but supposedly it IS a celebrated day on which many people across the country go hot-air ballooning.

Do Balloon Experiments

Balloon Blast-Off
Balloon in a Bottle
Balloon ON a Bottle
Yet Another Balloon on a Bottle
Balloon Brain



Balloon the Halls!

Blow up some balloons and rub them on carpet to create static electricity. Then carefully “hang” the balloons on the wall. (They should cling because of the electrical charge.)

Do this with a number of balloons. How long before the first balloon falls? The last? Can you do an experiment to test why the various balloons come down at different times?

Balloon Shrink-Art

Use a Sharpie fine point pen to carefully draw a picture on a well-inflated balloon. Try to keep your hand and fingers off of the lines you have already drawn, because the ink will smudge before it dries. Once your picture is complete, untie the balloon's knot and watch as your drawing shrinks up.

I've always liked how finely drawn and detailed these shrunken pictures look!

Watch "Up!"
This Disney-Pixar movie features a LOT of balloons!

January 8, 2010

Celebrate Galileo!

On this date in 1642, Galileo Galilei died. At 78 years of age, Galileo was blind and ill, and he had lived the last 8 years of his life under house arrest, although he was permitted to travel to doctors and to receive visitors.

House arrest? For one of the world's greatest scientists?

Galileo believed that the Earth moved around the Sun, rather than the reverse, and this seemed to go against some Biblical passages when interpreted literally. Because of this, there was controversy between Galileo, on one side, and the Pope, the Inquisition, and the Catholic Church, on the other. After a trial, Galileo was found guilty of heresy and placed under house arrest. (The Church has of course since then pardoned Galileo, and apologized as well, in 1992.)

Galileo's achievements

Yesterday marked the 400th anniversary of one of Galileo's achievements: observing some of Jupiter's moons. He didn't immediately know what they were—he labeled them “three fixed stars”—but as he observed the “stars” each night, he realized that they were circling Jupiter. A fourth appeared, as well. Galileo realized that they were moons orbiting another planet just as our moon orbits Earth.

This is one bit of evidence that Galileo was able to use when discussing the old idea that everything circled the Earth—these moons were clearly circling Jupiter, not Earth.

Galileo is credited with pioneering the experimental scientific method, building the first high-powered telescope, discovering the phases of Venus and sunspots, confirming the Copernican theory of the solar system, and developing many key ideas of physics. He demonstrated that the velocity of a falling body is not proportional to its weight (the experiment pictured below), described the parabolic paths of cannonballs, and invented a water pump.

Timeline of the greats

This timeline shows the lifetimes of some of the greats of the time: Michelangelo in green, Shakespeare in orange, Galileo in red, and Newton in purple.

Notice that Galileo was born the year Michelangelo died... and died just a few days after Isaac Newton was born. Using the birth and death years given, can you compute how old each of these men were when they died?


One of my favorite Galileo quotes:

“Mathematics is the language in which God wrote the universe.”

Galileo is often called the founder of modern science because, instead of merely sitting and pondering things, he did experiments and measured his data as carefully as he could. He also set up standards of length and time so that others could replicate his experiments at other times and places. But he went further: he used mathematics to reason out laws of motion and so forth.

Star gaze tonight!

Winter can be a great time to watch the skies, since in gets dark early. (Of course, it's not so good when it's cloudy!) Before you head outside, try checking out what you can expect to see. One site is the JPL “up?” videos.

Remember, you can study the skies even without a telescope. Maybe you can borrow a good pair of binoculars?

Do some experiments.
There are some good ideas here (halfway down the page, in blue; the first is called "Lunar Observation").

Do some virtual experiments.
This site has some great interactive demos (on the central panel) on the topics of falling objects, projectiles, inclined planes, and pendulums. Great stuff!

December 20, 2009

Electricity Theme Day

On this day in 1879, Thomas Edison privately demonstrated his incandescent light bulb at his Menlo Park research lab.

Remember, Edison didn't invent or even discover electricity (known from ancient times), and he didn't invent the first light bulb (Sir Humphrey Davy made an arc lamp in 1809, and Frederick de Moleyns got the first patent for an incandescent bulb in 1841). What Edison did was to make the first commercially practical light bulb and an entire system of electric lighting. Edison said on the last day of 1879, "We will make electricity so cheap that only the rich will burn candles."

<--1904

Today -->

On this day in 1880, Broadway in Manhattan, NYC, became one of the first streets in the U.S. lit by electricity. A mile of the street was lit by carbon-based Brush arc lamps, which provided much brighter light than the incandescent light bulbs of the time. Since then, that section of Broadway, which features the Theatre District and Times Square, has become known as “The Great White Way” because it is lit by millions of lights on marquees and billboards.

On this day in 1901, Robert J. Van de Graaf was born. This American physicist invented a high-voltage electrostatic generator, which looks like a large silver ball mounted on a pedestal. It makes your hair stand on end, but more importantly, it can be used as a particle accelerator in physics research.


On this day in 1938, Russian-American inventor Vladimir Zworykin (sometimes called the “true father of television,” although most give Philo Farnsworth that honor) was finally granted a patent for his iconoscope, an early television camera. (This camera had already been used for the historic TV transmission of the 1936 Olympic Games in Berlin.)


On this day in 1951, the first electricity ever generated by nuclear energy was created near Arco, Idaho. (The Experimental Breeder Reactor in Idaho produced enough energy to light four 200-watt light bulbs that day.)

By 1952, the Paley Commission was already somewhat pessimistic about nuclear power and called for “aggressive research in the whole field of solar energy.” And by 1955, the Arco Reactor was the first reactor in the U.S. to experience partial meltdown.


Have fun with this model of the electric force
Virtually speaking, create electrons and see if you can keep them from getting sucked into the positive-charged proton.

Do some electricity experiments!
Try the ideas here. Or here is a fun website.
These experiments are so easy, they're considered “snack size.”

Build electric circuits with information found here.

Learn more.
Here is an interactive course about electricity.
And here is an interactive diagram that shows the difference between AC (alternating current) and DC (direct current).

November 13, 2009

Harvest Festival – US Virgin Islands

There are more than 60 islands in the Virgin Islands archipelago—which means a chain of islands that has formed from volcanic action, often from an ocean plate moving over a hot spot under the earth's crust. The eastern portion of the chain makes up the British Virgin Islands, but the four westernmost islands (along with nearby tiny islands) are unincorporated territory of the United States. The four main islands are St. Croix, St. Thomas, St. John, and the much smaller Water Island.

Originally inhabited by Arawak, Carib, and Ciboney Indians, these islands were “discovered” and named by Christopher Columbus. All the natives died from disease and murder, and the islands were repopulated by European sugar plantation owners and African slaves. Today the islands are largely populated by Afro-Carribean descendants of slaves.

Residents of the US Virgin Islands are US citizens; they can vote in primary presidential elections, but not in the actual presidential elections; they have a representative in the House of Representatives, and he or she can vote in committee but cannot participate in floor votes.

The major language of both British and US Virgin Islands is English. Cars drive on the left side of the road on both sets of islands, like Britain, but steering wheels are on the left side of cars, like the US. Also, the US dollar is the currency used in both British and US Virgin Islands.

The combined area of all the US Virgin Islands is about twice the size of Washington, D.C.

How to Build an Island Chain

To demonstrate how an island chain forms, peel an orange carefully, making sure that there are several large pieces of peel. On the peeled orange, make a single dot with red food coloring. Then use one of the large pieces of peel to demonstrate the Atlantic plate moving slowly in one continuous direction. As it moves over the hot spot, a volcano forms above that hot spot; mark the peel with a small circle to represent a volcano (perhaps using a permanent marker), and then continue to move the peel in the same direction and continue marking volcanoes. Eventually, there is a chain of volcanic islands.



Make a Volcano

This is the age-old vinegar/baking soda experiment. If you've never done it, it is lots of fun!

There are all kinds of volcano activities at geology.com.