FREE BOOKS!!! July 4th - August 4th

Summer's here and it's time to catch up on your reading. Project Gutenberg is sponsoring the World eBook Fair beginning July 4th and running through August 4th and will be offered the same time next year. Over 300,000 titles will be offered, of those 95% are in the public domain (no longer copyright protected) and the other 5% have been donated by their copyright holders for this event. The books can be downloaded and read on almost any computer and some cellphones and PDAs. The idea behind this project is to give books away, to be copied and shared with others. The sponsors hope to encourage knowledge and battle illiteracy. Gregory Newby of Project Gutenberg, was quoted in the Boston Globe ("Free chapter added to saga of e-books" by David Mehegan) as saying, "It breaks my heart to go into Barnes & Noble and find Jane Austen for sale in a trade format. Where does that money go? It's close to profiteering. No author is getting any money for it. I feel sorry for schools, where kids are now reading Canterbury Tales or Huckleberry Finn, and the schools are spending millions of dollars from their budgets to buy the books. We're giving the stuff away for free."

Bring your PDA or laptop with you on summer vacation and enjoy a good book. You can learn more about Project Gutenberg by visiting their site at www.gutenberg.org.

Internet Field Guide

Yesterday, my son and I fished this little guy out of the swimming pool. What kind of frog is he we wondered? The Internet is such a great tool for home and at school, with a little help from a search engine we came across the National Wildlife Federation's Website which provides online field guides. We searched for frogs in New England and identified our find as a Grey Tree Frog. What is great about this site is not only does it have pictures of the frog in question (the Grey tree frog can be grey or green) but also its voice. The sound (or racket, depending on the time of day) that this frog makes is very distinctive and helped us to identify it.

With that in mind, if you have the opportunity to take your class into the field, bring along some kind of recording devices such as taperecorders and cameras and then search for your finds on the Internet. Great way to get students into the field and to become tech savvy at the same time.

Whodunnit-DNA the Secret Code of Life

Continuing with our secret code theme in the Whodunnit class, I presented DNA as the secret code of life. I explained the basics of DNA molecular structure and emphasized the "code" that was created by the 4 different nucleotides. The cipher for our secret code is C=G and A=T (cytosine always pairs with guanine and adenine with thymine in the double helix).

We created this DNA Model using chenille stems (pipe cleaners) and pony beads. The original directions for this activity (see link above) used fishing line or plastic thread in order to make a bracelet, which I thought might not be too interesting for the boys in the class or easy for students with fine motor skill issues. I had the students bend one end of the pipe cleaner so the beads would not fall off while they were working. The Ology site provided a short list of animal and plant gene sequences (the pipe cleaners can hold 40 beads well) which I typed up for the students. The first step was to decode the other strand of DNA using the cipher C=G and A=T. Then the students could chose 4 different color beads assigning one color to each of the 4 nucleotide bases (i.e. in the model shown blue=thymine, orange=adenine, green=cytosine and pink=guanine). The visual aid helped to cement the concept of base pairing, every time I use a pink(guanine) on the other strand of DNA there will be a green (cytosine) to pair up with it when the two strands are placed next to one another. The last step was to twist the two strands together to create the helix.

Steganography

"Steganography is the technique of concealing the fact that a message ever existed. The most common way to do this is by using secret inks or microdots." (Page 50, from Spy's Survival Handbook written by Laban Carrick Hill, Scholastic c.2003)

Over the years, I have repeatedly tried to find a way to use lemon juice writing with kids without using an open flame to expose the hidden message. I tried the naked light bulb method (according to some resources I looked up today you need at least a 100 watt bulb), and a bright flashlight; neither were successful. Success was found when I read the suggestion to use an iron. This photograph shows a message I created for my class last week, it was left behind as a clue. A couple of students were quick to pick up the idea that a blank piece of paper in the middle of the crime scene might not be blank at all but a secret message. There are several methods for producing secret ink messages. The preceding link lists several methods and I plan on trying out the lemon juice writing revealed by red cabbage liquid. This method would be a great segue into using red cabbage liquid as a acid/base indicator. But that's another blog posting for the future.

Each student produced their own secret message during class. I brought fresh lemons, cut them and squeezed the juice into plastic cups for the kids. Using a Q-tip, the kids wrote their messages, once dry we pressed them with the iron (use a folded towel to cover your table surface, I happen to own a pressing pad a by product of my quilting hobby-handy for taking to sewing classes) using the high setting. Eureka! The messages were revealed.

Chromatography

Chromatography is a method of separating molecules based on size and rate of travel through a medium. For this week's Whodunnit class we used paper chromatography in order to identify which pen was used to sign the birth certificate of the fictional Princess Michaeala who had been kidnapped at birth. The Royal family managed to retain a portion of the original document and the kidnappers absconded with the rest of it. When a young woman resurfaced claiming to be the Princess (I likened it to the animated movie Anastasia that children would be familiar with) the torn document that she possessed would be tested against the existing piece in the Royal archives and the against the original pen used by the Registrar of Births.

Each student was provided with the following evidence sheet on which I had attached a strip of filter paper (coffee filter) with a sample of ink from the Registrar's pen which had been processed by chromatography. The students were then given three samples to test in order to find the matching ink pattern. In a clear plastic cup, I placed a half inch of acetone nail polish remover and the students placed their samples. We allowed the samples to rest for 10 minutes. The capillary action of the filter paper did the rest. Students removed their samples and placed them on wax paper (to protect desk surfaces) to dry. Then they compared the samples to the one provided and made a match. The documents in question were a match, no case of forgery. But is the Princess herself the real thing. That will bring us to the next topic, DNA testing.

More Secret Codes

We continued working with secret codes this week in Whodunnit? I introduced the classic alpha-numeric substitution code but with a twist. The cipher key showed a table with A=1, B=2 all the way to Z=26, however the code itself showed a number problem in parentheses such as (4+3) which equals 7 and therefore stands for the letter G. For example the word cat would be (2+1)(5-4)(10+10). You could create a variety of math fact problems for each letter of the alphabet using addition, subtraction, multiplication and division depending on your grade level.