TED-Ed's New Interactive Periodic Table

 TED-Ed's new interactive periodic table

TED-Ed launches an interactive periodic table with a video for every element If you’ve ever taken a chemistry class, you know that memorizing all of the elements and understanding their properties can be difficult! To help provide a study aid, TED-Ed collaborated with Brady Haran, best known for his YouTube channel Numberphile and his extensive video coverage of the periodic table, to create a clickable periodic table with videos on every element. Click around the table »

source:
http://us4.campaign-archive1.com/?u=367d080dac70911f825f109f9&id=92b1054add&e=4411419a30

Measure the Speed of Light using a Chocolate Bar

Step 1. check the Shopping List:

This is a very short shopping list for a super-cool activity that is used in college-level physics labs!

• A large 1 lb. bar of chocolate (I use Hershey's, but any kind should do)
• A ruler, pencil and paper
• A microwave oven and a plate

---

Step 2. Do the activity yourself:

Measure the Speed of Light using a Chocolate Bar

When you warm up leftovers, have you ever wondered why the microwave heats the food and not the plate? (Well, some plates, anyway.) It has to do with the way microwave ovens work.
Microwave ovens use dielectric heating (or high frequency heating) to heat your food. Basically, the microwave oven shoots light beams that are tuned to excite the water molecule. Foods that contain water will step up a notch in energy levels as heat. (The microwave radiation can also excite other polarized molecules in addition to the water molecule, which is why some plates also get hot.)

One of the biggest challenges with measuring the speed of light is light travels really fast… too fast to watch with our eyeballs.  So instead, we're going to watch the effects of microwave light and base our measurements on the effects the light has on different kinds of food.  What's really cool about this experiment that you can see the size of the wave for yourself by measuring the burn marks in the chocolate. Microwaves use light with a wavelength of 0.01 to 10 cm (that's the size of the wave itself).

Key Concepts

Energy can take one of two forms: matter and light (called electromagnetic radiation). Matter is what stuff is made from, like a chair or a table, and we'll talk a lot more about matter when we get to chemistry.
Light is energy that can travel through space and through some kinds of matter, like glass. Another word for light is “electromagnetic radiation”. Light can have high energy, lower energy, or anything in between… kind of like high energy kids (the ones who race all over the playground), lower energy kids (the ones reading a book in a corner), and kids whose energy is somewhere in the middle.
Scientists usually refer to the light energy you can see with your eyes as “visible light”, or just “light”, and it has middle-of-the-road amounts of energy – not high, not low. Just average. That kind of electromagnetic radiation is called “light”.

Lower energy electromagnetic radiation can have wavelengths longer than a football field, and those are called “radio waves”. These aren't the kind of waves that a guitar string makes when you pluck it. Radio waves are not sound waves. They are waves made out of electricity and magnetism (which we'll discuss later) that travel through space. Sound waves need something, like air, in order to travel because it does it by vibrating molecules. Electromagnetic waves work differently, but it's a little more complicated than we're going to discuss now, so just remember that light waves are different than sound waves. If you've ever seen a lightning storm, you know this is true, because you see the lightning way before you hear the thunder. Which wave do you think travels faster? Light or sound? Other examples of lower energy waves are the kind found in your microwave oven called “microwaves” (surprised?) Your TV remote uses infra-red electromagnetic radiation, which has a little more energy than microwaves. What about high energy waves? If you've ever been curious about why the dentist puts a heavy lead apron on you before x-raying your teeth, it's because they're about to use high-energy electromagnetic radiation called “x-rays” to see through your mouth tissues to get to the bones and teeth. Since high-energy rays can destroy living tissue, you have to wear that apron. Lead stops most high-energy electromagnetic radiation in the x-ray range. Black holes, supernovae, and quasars in the deep reaches of space emit deadly x-rays and even higher-energy gamma rays.

Experiment 

Video  http://www.superchargedscience.com/lnc813-16.htm

Materials:

• chocolate bar (extra-large bars work best)
• microwave
• plate
• ruler
• calculator
• pencil and paper

 

1. First, you'll need to find the ‘hot spots' in your microwave. 
2. Remove the turntable from your microwave and place a naked bar of chocolate on a plate inside the microwave. 
3. Make sure the chocolate bar is the BIG size – you'll need at least 7 inches of chocolate for this to work.
4. Turn the microwave on and wait a few minutes until you see small parts of the chocolate bar start to bubble up, and then quickly open the door (it will start to smoke if you leave it in too long). 
5. Look carefully at the chocolate bar without touching the surface… you are looking for TWO hotspots, not just one – they will look like small volcano eruptions on the surface of the bar.  If you don't have two, grab a fresh plate (you can reuse the chocolate bar) and try again, changing the location of the place inside the microwave. 
6. You're looking for the place where the microwave light hits the chocolate bar in two spots so you can measure the distance between the spots. Those places are the places where the microwave light wave hits the chocolate.
7. Open up the door or look on the back of your microwave for the technical specifications.  You're looking for a frequency in the 2,000-3,000 MHz range, usually about 2450 MHz. 
8. Write this number down on a sheet of paper – this tells you the microwave radiation frequency that the oven produces, and will be used for calculating the speed of light. (Be sure to run your experiment a few times before taking actual data, to be sure you've got everything running smoothly.  Have someone snap a photo of you getting ready to test, just for fun!)

Going further: You can experiment with other easy-to-melt foods, like cheese, buttered bread, chocolate chips, peanut butter, or marshmallows! Just pop in the first food type on a plate (without the turntable!) into the best spot in the microwave, and turn it on.  Remove when both hotspots form, and being careful not to touch the surface of the food, measure the center-to-center distance using your ruler in centimeters.
TIP: If you're using mini-marshmallows or chocolate chips (or other smaller foods), you'll need to spread them out in an even layer on your plate so you don't miss a spot that could be your hotspot!

How to Calculate the Speed of Light from your Data

Note that when you measure the distance between the hotspots, you are only measuring the peak-to-peak distance of the wave, which means you're only measuring half of the wave.  We'll multiply this number by two to get the actual length of the wave (wavelength).  If you're using centimeters, you'll also need to convert those to meters by dividing by 100.
So, if you measure 6.2 cm between your hotspots, and you want to calculate the speed of light and compare to the published value which is in meters per second, here's what you do:

2,450 MHz is really 2,450,000,000 Hz or 2,450,000,000 cycles per 1 second

Find the length of the wave (in cm):

2 * 6.2 cm = (12.4 cm) /(100 cm/m) = 0.124 meters

Multiply the wavelength by the microwave oven frequency:

0.124 m * 2,450,000,000 Hz = 303,800,000 m/s

The real (published) value for light speed is 299,792,458 m/s = 186,000 miles/second = 671,000,000 mph. How did you do?

Questions to Ask

1. What would happen if you used cheese instead of chocolate?
   
2. Does it matter where in the microwave the chocolate is located? Does placement of the chocolate affect the wavelength?
   
3. Can you explain what the burn marks on the chocolate bar are from?
   

Nutrition - Nova (Dying to be Thin)

Why do we eat? How do our bodies use the foods we eat? What organ or system in your body may not be getting enough of what it needs? This interactive feature from NOVA "Dying to Be Thin" Web site will fill you in. Just click on a body part or on the name of a nutrient to find out what you need to eat to stay healthy.

VIEW

• Media Type: Interactive
• Size: 121.0 KB
• Level: Grades 3-8
• 
  Log in to Teachers' Domain to download, share, rate, save, and match to state standards.

Source: NOVA: "Dying to Be Thin" Web site
This resource can be found on the NOVA: "Dying to Be Thin" Web site.

Background

Standards of beauty have changed over the years. In the late 1800s, advertisers regularly used models who would be considered overweight by today's standards. Times have changed dramatically. Most Americans are exposed to thousands of media messages every day -- in magazines and newspapers, on television, on outdoor billboards, and over the Internet. These messages promote bodies that are thin and, in some cases, unrealistically proportioned, and they are creating a culture of young people who are obsessed with losing weight.

As a result of this obsession, many people have sworn off fat. They avoid eating fat in any form and, instead, obtain most of their calories from carbohydrates, like bread and pasta. For decades, doctors and health experts supported this fat-free nutritional strategy. Fat was the enemy, they said; it was the cause of obesity and heart disease. Carbohydrates were your friends and could be consumed, many thought, in mass quantities with few concerns about health consequences. Recent studies, however, have begun to reveal the flaws in this thinking.

A nutritional plan that shuns fat ignores this food's important role in the body. While fat's main purpose is to store energy, it serves many other functions as well. Either in its whole form or broken down into small molecules, fat does the following: provides insulation, builds membranes, aids digestion, promotes proper nervous system function, regulates hormones, keeps the skin healthy, and aids the chemical communication between cells. And these are just a few of the important things that fat does for us. Still, many people continue on a fat-free path.

Somewhat surprisingly, fat-free diets often result in the accumulation of excess body fat. Carbohydrates, including sugars and starchy foods, provide the body's most efficient form of energy. They are broken down quickly into glucose, the sugar that cells need in order to function. This is why energy bars used by athletes are made up primarily of carbohydrates: They are quickly broken down in the stomach, and the resulting sugars are easily transported throughout the body via the bloodstream.

When the body is active at high intensity for long periods of time, carbohydrates must be eaten regularly to provide the cells with the energy they need. Carbohydrates that are consumed when the body is at rest, however, are stored. Relatively small amounts of carbohydrates can be stored in the muscles and the liver as a complex sugar called glycogen. When glycogen stores are full, however, and there is no further demand for sugar, carbohydrates are stored as fat.

Although most doctors and nutritionists still recommend that people get the majority of their calories from carbohydrates, they also suggest that many people would benefit from increasing their fat intake. According to most nutritionists, the ratio of carbohydrate, fat, and protein calories should, in fact, be much closer to equal -- at 40, 30, and 30 percent respectively. They stress that exercising and eating moderately from all of the food groups is the proper path to better health.

Questions for Discussion

• Could you stay healthy eating three or fewer of the foods shown here? Explain your answer, using information from the site.
• Why do you think 75 percent of the U.S. population doesn't meet daily recommended dietary needs? What ideas do you have about changing the nutritional habits of people in this country?

SOURCE: http://www.pbs.org/wgbh/nova/education/body/body-needs.html?elq=0937217e29c949998c57be7bcd65db11&elqCampaignId=431

DNA - Nova

 VIEW

DNA. It's what makes you unique. Unless you have an identical twin, your DNA is different from that of every other person in the world. And that’s what makes DNA fingerprinting possible. Experts can use DNA fingerprints for everything from determining a biological mother or father to identifying the suspect of a crime. What, then, is a DNA fingerprint and how is it made? Here, you'll find out by solving a mystery—a crime of sorts. First, you’ll create a DNA fingerprint (we'll supply the lab and all necessary materials). Then you’ll compare this DNA fingerprint to those of all seven suspects to nab the perpetrator. Ready? Let's get to work!

VIEW

• Media Type: Interactive
• Size: 283.0 KB
• Level: Grades 6-12
• Log in to Teachers' Domain to download, share, rate, save, and match to state standards.

Source: NOVA: "The Killer's Trail" Web site
This feature originally appeared, in a different design, on the site for the NOVA program .

Background

In the last 15 years, DNA has played an increasingly important role in our legal system. Tissue evidence is now routinely collected during criminal investigations in hopes that it will provide genetic clues linking suspected criminals to crimes.

DNA profiles help forensic investigators determine whether two tissue samples -- one from the crime scene and one from a suspect -- came from the same individual. Fortunately, the genetic comparison doesn't require that investigators look at all of the DNA found in the tissue samples. That would take months or even years. Instead, by marking a small number of segments of DNA in one sample and then checking for the presence or absence of those segments in the other sample, investigators can say with some assurance whether the samples are from the same person.

How do they do it? Investigators use chemicals to cut the long strands of DNA into much smaller segments. Each segment has a specific length, but all of them share the same repeating sequence of bases (or nucleotides). The chemicals cut the segments at the beginning and at the end of the repeating string of nucleotides, so one segment might be ATCATCATCATCATC, for example, while another might be ATCATC. (The DNA segments used in forensic investigations are, of course, much longer than this.)

Investigators use a process called gel electrophoresis to separate these repeating segments according to length. Next, they introduce a small set of radioactive "markers" to the sample. These markers are segments of DNA of known length, with bases that complement the code of, and bind to, sample segments of the same length. The sample segment above (ATCATCATCATCATC), for example, would be tagged by a marker with the complementary code TAGTAGTAGTAGTAG.

Markers that do not bind to sample segments are then rinsed away, leaving in place only those markers that bound to complementary sample segments. Photographic film, which darkens when exposed to the radioactive markers, identifies the location of all marked sample segments. This film, then, becomes the DNA "fingerprint" that forensic investigators analyze.

The final step is a relatively simple matter of lining up the sample profiles side by side and comparing them for the presence or absence of segments with particular lengths. The more segments the two samples have in common, the more likely it is that the samples came from the same person.

Questions for Discussion

• Describe the process of DNA fingerprinting.
• In what ways is it like actual fingerprinting and in what ways is it different?
• How conclusive is the evidence of DNA fingerprinting?
• Where is there possibility for error?

SOURCE: http://www.pbs.org/wgbh/nova/education/body/create-dna-fingerprint.html?elq=0937217e29c949998c57be7bcd65db11&elqCampaignId=431

BPA Timeline

source: http://www.jsonline.com/watchdog/watchdogreports/34532374.html 
Nov 15, 2008

Watchdog Reports      The history of BPA     TIMELINE


1891: Bisphenol A, or BPA, is developed.

1930s: The chemical is used as a synthetic estrogen.

1960s: Food manufacturers begin to use BPA to make hard, clear plastic for items such as baby bottles and the lining of metal food cans, including liquid baby formula.

1998: Patricia Hunt, a geneticist at Washington State University, notices that control mice had many more defective eggs when stored in polycarbonate cages.

2000-present: More than 1,000 studies are published showing harm to lab animals from BPA, including cancer, obesity, diabetes, reproductive failures and neurological disorders.

2008: Annual sales of BPA exceed $6 billion.
April 2008: Canadian health officials begin steps to declare BPA a toxin and to have it banned from use in baby bottles and tableware for children. Several manufacturers - including Nalgene, Wal-Mart, Toys "R" Us and CVS pharmacies - announce plans to phase out use of the chemical in children's products.

August 2008: The Food and Drug Administration declares BPA to be safe.

September 2008: The National Toxicology Program, an advisory board to the FDA and Environmental Protection Agency, releases its report expressing some concern for how BPA affects the prostate and neural development of fetuses, infants and children. It also expressed concern about the chemical's effect on breast tissue and early puberty.

A study published in the Journal of the American Medical Association in September tied BPA to heart disease in humans. Lawmakers start to call for a ban of the chemical in children's products.

October 2008: The FDA's Science Board finds that the FDA ignored hundreds of studies on BPA and advises the agency to reopen its investigation of the chemical. A study finds that even low levels of BPA can interfere with chemotherapy for breast cancer patients.

Related Coverage

• Watchdog Report: BPA leaches from 'safe' products
• How The Story Was Reported: Putting the products to the test
• Background: The history of BPA
• PDF: How to avoid bisphenol A
• PDF: BPA results
• Responses: E-mails from companies mentioned in this article
• Statement: American Chemistry Council response
• Special Section: Chemical Fallout

BIg Chem; Big Harm? (NYT)

Son, this is one reason I have worked so hard to find a place to shop that doesn't have ANY harmful chemicals in their products.  You know my favorite store.  You may also want to click here after reading this article. ;-) This is an important science lesson.The assignment details follow the article.

BIG CHEM; BIG HARM?

by Nicolas Kristof

                                                                  edited by Mom

NEW research is demonstrating that some common chemicals all around us may be even more harmful than previously thought. It seems that they may damage us in ways that are transmitted generation after generation, imperiling not only us but also our descendants.

Yet following the script of Big Tobacco a generation ago, Big Chem has, so far, blocked any serious regulation of these endocrine disruptors, so called because they play havoc with hormones in the body’s endocrine system. 

One of the most common and alarming is bisphenol-A, better known as BPA. The failure to regulate it means that it is unavoidable. BPA is found in everything from plastics to canned food to A.T.M. receipts. More than 90 percent of Americans have it in their urine. 

Even before the latest research showing multigeneration effects, studies had linked BPA to breast cancer and diabetes, as well as to hyperactivity, aggression and depression in children.

Maybe it seems surprising to read a newspaper column about chemical safety because this isn’t an issue in the presidential campaign or even firmly on the national agenda. It’s not the kind of thing that we in the news media cover much. 

Yet the evidence is growing that these are significant threats of a kind that Washington continually fails to protect Americans from. The challenge is that they involve complex science and considerable uncertainty, and the chemical companies — like the tobacco companies before them — create financial incentives to encourage politicians to sit on the fence. So nothing happens. 

Yet although industry has, so far, been able to block broad national curbs on BPA, new findings on transgenerational effects may finally put a dent in Big Chem’s lobbying efforts. 

One good sign: In late July, a Senate committee, for the first, time passed the Safe Chemicals Act, landmark legislation sponsored by Senator Frank Lautenberg, a New Jersey Democrat, that would begin to regulate the safety of chemicals. 

Evidence of transgenerational effects of endocrine disruptors has been growing for a half-dozen years, but it mostly involved higher doses than humans would typically encounter.

Now Endocrinology, a peer-reviewed journal, has published a study measuring the impact of low doses of BPA. The study is devastating for the chemical industry.

THE EXPERIMENT:
Pregnant mice were exposed to BPA at dosages analogous to those humans typically receive. 

WHAT HAPPENED:
1) The offspring were less sociable than control mice (using metrics often used to assess an aspect of autism in humans), and various effects were also evident for the next three generations of mice. 

WHY?

The BPA seemed to interfere with the way the animals processed hormones like oxytocin and vasopressin, which affect trust and warm feelings. And while mice are not humans, research on mouse behavior is a standard way to evaluate new drugs or to measure the impact of chemicals. 

CLARIFICATION & COMMENTS by authors of the report

“It’s scary,” said Jennifer T. Wolstenholme, a postdoctoral fellow at the University of Virginia and the lead author of the report. She said that the researchers found behaviors in BPA-exposed mice and their descendants that may parallel autism spectrum disorder or attention deficit disorder in humans. 

Emilie Rissman, a co-author who is professor of biochemistry and molecular genetics at University of Virginia Medical School, noted that BPA doesn’t cause mutations in DNA. Rather, the impact is “epigenetic” — one of the hot concepts in biology these days — meaning that changes are transmitted not in DNA but by affecting the way genes are turned on and off.  These results at low doses add profoundly to concerns about endocrine disruptors,” said John Peterson Myers, chief scientist at Environmental Health Sciences. “It’s going to be harder than just eliminating exposure to one generation.” 

SCIENCE HISTORY NOTE:  In effect, this (epigenetic impact) is a bit like evolution through transmission of acquired characteristics — the theory of Jean-Baptiste Lamarck, the 19th-century scientist whom high school science classes make fun of as a foil to Charles Darwin. In epigenetics, Lamarck lives. 

The National Institutes of Health is concerned enough that it expects to make transgenerational impacts of endocrine disruptors a priority for research funding, according to a spokeswoman, Robin Mackar.

In his conclusion, the author of this New York Times Article offers his two cents:

Like a lot of Americans, I used to be skeptical of risks from chemicals like endocrine disruptors that are all around us. What could be safer than canned food? I figured that opposition came from tree-hugging Luddites prone to conspiracy theories.

Yet, a few years ago, I began to read the peer-reviewed journal articles, and it became obvious that the opposition to endocrine disruptors is led by toxicologists, endocrinologists, urologists and pediatricians. These are serious scientists, yet they don’t often have the ear of politicians or journalists.

I’m hoping these new studies can help vault the issue onto the national stage. Threats to us need to be addressed, even if they come not from Iranian nuclear weapons, but from things as banal as canned soup and A.T.M. receipts.

ORIGINAL SOURCE:
New York Times Article - Big Chem; Big Harm?
by NICHOLAS D. KRISTOF
Published: August 25, 2012

ASSIGNMENT:  
1) Read this New York Times article. Read a second time and take key word notes
I have edited with notes in red to keep you focused on important points.
2) VOCABULARY: Define and memorize the 20 bolded words or terms.  You already know many of the words and numerous other words can defined contextually.
3) Make sure you understand and memorize the 2 bolded sentences.
4) Become familiar enough with the article that you are ready to discuss it.
5)  Complete a re-write in your own words by Monday.
5) We can discuss this after dinner tonight.  :-)


Also see: http://kristof.blogs.nytimes.com/
 

Scientific Method

Key Info

• The scientific method is a way to ask and answer scientific questions by making observations and doing experiments.
• The steps of the scientific method are to:
  • Ask a Question
  • Do Background Research
  • Construct a Hypothesis
  • Test Your Hypothesis by Doing an Experiment
  • Analyze Your Data and Draw a Conclusion
  • Communicate Your Results
• It is important for your experiment to be a fair test. A "fair test" occurs when you change only one factor (variable) and keep all other conditions the same.
• While scientists study how nature works, engineers create new things, such as products, websites, environments, and experiences.
  • If your project involves creating or inventing something new, your project might better fit the steps of the Engineering Design Process.
  • If you are not sure if your project is a scientific or engineering project, you should read Comparing the Engineering Design Process and the Scientific Method.
  
  
  

  Overview of the Scientific Method

  The scientific method is a process for experimentation that is used to explore observations and answer questions. Scientists use the scientific method to search for cause and effect relationships in nature. In other words, they design an experiment so that changes to one item cause something else to vary in a predictable way.
  Just as it does for a professional scientist, the scientific method will help you to focus your science fair project question, construct a hypothesis, design, execute, and evaluate your experiment.
  

  

  
  
  

  Steps of the Scientific Method	Detailed Help for Each Step
  Ask a Question: The scientific method starts when you ask a question about something that you observe: How, What, When, Who, Which, Why, or Where? And, in order for the scientific method to answer the question it must be about something that you can measure, preferably with a number.	Your Question
  Do Background Research: Rather than starting from scratch in putting together a plan for answering your question, you want to be a savvy scientist using library and Internet research to help you find the best way to do things and insure that you don't repeat mistakes from the past.	Background Research Plan Finding Information Bibliography Research Paper
  Construct a Hypothesis: A hypothesis is an educated guess about how things work: "If _____[I do this] _____, then _____[this]_____ will happen." You must state your hypothesis in a way that you can easily measure, and of course, your hypothesis should be constructed in a way to help you answer your original question.	Variables Variables for Beginners Hypothesis
  Test Your Hypothesis by Doing an Experiment: Your experiment tests whether your hypothesis is true or false. It is important for your experiment to be a fair test. You conduct a fair test by making sure that you change only one factor at a time while keeping all other conditions the same. You should also repeat your experiments several times to make sure that the first results weren't just an accident.	Experimental Procedure Materials List Conducting an Experiment
  Analyze Your Data and Draw a Conclusion: Once your experiment is complete, you collect your measurements and analyze them to see if your hypothesis is true or false. Scientists often find that their hypothesis was false, and in such cases they will construct a new hypothesis starting the entire process of the scientific method over again. Even if they find that their hypothesis was true, they may want to test it again in a new way.	Data Analysis & Graphs Conclusions
  Communicate Your Results: To complete your science fair project you will communicate your results to others in a final report and/or a display board. Professional scientists do almost exactly the same thing by publishing their final report in a scientific journal or by presenting their results on a poster at a scientific meeting.	Final Report Abstract Display Board Science Fair Judging

  Even though we show the scientific method as a series of steps, keep in mind that new information or thinking might cause a scientist to back up and repeat steps at any point during the process. A process like the scientific method that involves such backing up and repeating is called an iterative process.
  Throughout the process of doing your science fair project, you should keep a journal containing all of your important ideas and information. This journal is called a laboratory notebook.
  
  LINKS:  Steps of the Scientific Method
  

  Key Info

  Overview of the Scientific Method

   

  SOURCE: 

  http://www.sciencebuddies.org/  

  http://www.sciencebuddies.org/science-fair-projects/project_scientific_method.shtml

  
  
  
  

Franklin Bell & Leyden Jar

Franklin bells are an early demonstration of electric charge designed to work with a *Leyden jar. They were invented by Benjamin Franklin in the 18th century during his experimentation with electricity. Franklin bells are only a qualitative indicator of electric charge and were used for simple demonstrations rather than research.

The bells consist of a metal stand with a crossbar, from which hang three bells. The outer two bells hang from conductive metal chains, while the central bell hangs from a nonconductive thread. In the spaces between these bells hang two metal clappers, small pendulums, which hang from nonconductive threads. A short metal chain hangs from the central bell.

The central bell's chain is put in contact with the inner surface of a * Leyden jar, while the outside surface of the jar is put in contact with the metal stand. The central bell takes its charge from the inner surface of the jar, while the outer surface charges the two bells on the conductive chains; this causes the bells to have a potential difference equal to that between the inner and outer surfaces of the jar. The hanging metal clappers will be attracted to one bell, will touch it, pick up its charge, and be repelled; they will then swing across to the other bell, and do the same there. Each time the clappers touch a bell, charge is transferred between the inner and outer surfaces of the *Leyden jar. When the jar is completely discharged, the bells will stop ringing.

Electric Fly Swatter + Coke Can = Franklin's Bell 

http://www.youtube.com/watch?v=jIL0ze6_GIY&feature=related 


What is a Leyden Jar?

A Leyden jar, or Leiden jar, is a device that "stores" static electricity between two electrodes on the inside and outside of a glass jar. It was the original form of the capacitor.

It was invented independently by German cleric Ewald Georg von Kleist on 11 October 1745 and by Dutch scientist Pieter van Musschenbroek of Leiden (Leyden) in 1745–1746.^[1] The invention was named for this city.

The Leyden jar was used to conduct many early experiments in electricity, and its discovery was of fundamental importance in the study of electricity. Previously, researchers had to resort to insulated conductors of large dimensions to store a charge. The Leyden jar provided a much more compact alternative.

Chemistry Jokes and Riddles

Q: Anyone know any jokes about sodium?
A: Na

Making bad chemistry jokes because all the good ones Argon 

Q: What is the most important rule in chemistry?
A: Never lick the spoon! 

 

Helium walks into a bar,
The bar tender says "We don't serve noble gasses in here."
Helium doesn't react. 

Silver walks up to Gold in a bar and says, "AU, get outta here!" 

Two chemists go into a restaurant.
The first one says "I think I'll have an H2O."
The second one says "I think I'll have an H2O too" -- and he died. 

Q: What did the scientist say when he found 2 isotopes of helium?
A: HeHe 

Q: Why was the mole of oxygen molecules excited when he walked out of the singles bar?
A: He got Avogadro's number! 

A proton and a neutron are walking down the street.
The proton says, "Wait, I dropped an electron help me look for it."
The neutron says "Are you sure?" The proton replies "I'm positive." 

Money has recently been discovered to be a not-yet-identified super heavy element.
The proposed name is: Un-obtainium. 

As an ion chromatography chemist I made this one up:
Anions aren't negative, they're just misunderstood. 

The optimist sees the glass half full.
The pessimist sees the glass half empty.
The chemist see the glass completely full, half in the liquid state and half in the vapor state.

 

Q: What do chemists call a benzene ring with iron atoms replacing the carbon atoms?
A: A ferrous wheel.

 

Q: If H₂O is the formula for water, what is the formula for ice?
A: H₂O cubed.

 

Q: What did the bartender say when oxygen, hydrogen, sulfur, sodium, and phosphorous walked into his bar?
A: OH SNaP!

A neutron walks into a bar. He asks the bartender, "How much for a beer?" The bartender offers him a warm smile and says, "For you, no charge".

 

Q: What do you do with a dead chemist?
A: Barium

 

Q: What did one ion say to the other?
A: I've got my ion you.

 

Q: Why did the chemist sole and heel his shoes with silicone rubber?
A: To reduce his carbon footprint.

 

Q: What do you call a tooth in a glass of water?
A: One molar solution.

A small piece of sodium that lived in a test tube fell in love with a Bunsen burner. "Oh Bunsen, my flame," the sodium pined. "I melt whenever I see you," The Bunsen burner replied, "It's just a phase you're going through."

 

Q: What do you call a clown who's in jail?
A: A silicon.

 

Q: Why do chemists enjoy working with ammonia?
A: Because it's pretty basic stuff.

 

Q: What emotional disorder does a gas chomatograph suffer from?
A: Separation anxiety.

 

Q: Why does hamburger yield lower energy than steak?
A: Because it's in the ground state.

Florence Flask was getting ready for the opera. All of a sudden, she screamed: "Erlenmeyer, my joules! Somebody has stolen my joules!" The husband replied, "Calm down, honey. We'll find a solution."

 

Q: If H₂0 is water, what is H₂0₄?
A: Drinking, bathing, washing, swimming, etc.

Titanium is a most amorous metal. When it gets hot, it'll combine with anything.

 

Q: What did one titration say to the other?
A: "Let's meet at the endpoint."

 

Q: What did the Mass Spectrometer say to the Gas Chromatograph?
A: Breaking up is hard to do.

Old chemists never die, they just stop reacting.

 

Q: What is "HIJKLMNO"?
A: H2O.

 

Q: When one physicist asks another, "What's new?" what's the typical response?
A:C over lambda.

 

Q: How did the chemist survive the famine?
A: By subsisting on titrations.

 

Q: What happens when spectroscopists are idle?
A: They turn from notating nuclear spins to notating unclear puns.

If you're not part of the solution, you're part of the precipitate.

 

Q: Why can't lawyers do NMR?
A: Bar magnets have poor homogeneity.

 

Q: What element is derived from a Norse god?
A: Thorium.

 

Q: What happened to the man who was stopped for having sodium chloride and a nine-volt in his car?
A: He was booked for a salt and battery.

 

Q: What element is a girl's future best friend?
A: Carbon.

Little Willie was a chemist. Little Willie is no more. What he thought was H₂O was H₂SO₄.

 

Q: What is the name of 007's Eskimo cousin?
A: Polar Bond.

Composite Materials Lesson (level 9-12)

http://www.teachersdomain.org/resource/npe11.sci.engin.design.composites/

In this video segment adapted from NASA 360, learn about composite materials and how they are being used in spacecraft design at NASA. Composites are known primarily for the enhanced strength and stiffness they give to objects, such as airplane wings, while being lighter than conventional materials. Objects made from composites can also hold their shape better and not experience fatigue under heat or pressure. In the video, a NASA engineer explains how and why composites are being used in place of metals in a prototype crew module design.

Background Essay

While many products we use in our lives are made of a single material like solid wood, cotton, or aluminum, more and more are made of composites. A composite is a combination of different materials, called constituents. Composites offer certain performance advantages because the constituents work together to give the resulting object special properties. Most composites are made from two or more constituent materials: a binder, or matrix, which surrounds a reinforcement. Not all composites are the product of modern advanced technology. One common example is concrete. In concrete, cement (the binder) is combined with gravel (the reinforcement).

In deciding to use one material or composite over another, engineers consider many factors, among them strength, weight, corrosion resistance, and cost. Depending on the application, other factors may also matter. In developing the next-generation space capsule, NASA engineers need materials that are strong and lightweight (or technically, less massive) but also highly shapeable and resistant to extreme temperatures and fatigue. Before settling on a solution, these engineers will have conducted multiple tests to ensure that the composite fulfills all of these needs.

While spacecraft are still largely made of metal, NASA has begun investigating alternative materials that fulfill its safety objectives but offer performance advantages. The next-generation Space Shuttle Program for manned space exploration includes a newly designed mission crew module—the part of the spacecraft the astronauts will occupy. The design being evaluated, called a composite crew module, or CCM, is made of a carbon-graphite epoxy resin composite. This means that layers of carbon fiber—a material that is just as strong or stronger than steel, at about one-fifth the mass—with graphite reinforcement will cover an aluminum honeycomb shape. The “sandwich” structure will be coated in epoxy resin and cured, or hardened, in a kind of pressure oven called an autoclave. The resulting module will possess considerable strength and be much lighter than if it were made entirely of aluminum. It will be shaped to fit into the International Space Station when docking in space, and its heat shield, located at the bottom of the module, will also be able to withstand reentry temperatures of 3000°F (1650°C).

Composite materials feature in designs beyond spacecraft. Among the many industries already using them is the auto industry. As you might expect in an era of rising fuel prices, car companies are looking for ways to combine strength with weight reduction to improve fuel efficiency. As a result, many have begun developing designs that feature a carbon-fiber body in place of the usual steel and fiberglass. Because of its high ratio of strength to weight, carbon fiber is also used in a variety of consumer products besides cars, including tennis rackets, golf clubs, fishing rods, and bicycles.

Discussion Questions

Before the Video

• What substances can you think of that are made of two or more things with very different individual properties than the combination they form?

After the Video

• What is a composite material?
• Give an example of a composite material and explain its possible advantages and disadvantages.
• How do you think you could create a composite material yourself?
• The auto industry has begun to use a carbon fiber composite in place of fiberglass. Knowing what you do about carbon fiber, why do you think it’s doing this?

Texas

Subchapter B. Middle School

§112.22 Knowledge and skills

(6.7) Science concepts. The student knows that substances have physical and chemical properties.

(A) Demonstrate that new substances can be made when two or more substances are chemically combined and compare the properties of the new substances to the original substances

§112.24 Knowledge and skills

(8.5) Scientific processes. The student knows that relationships exist between science and technology.

(B) Design and test a model to solve the problem

Topology: Quarters, Dimes, Index Card, Scissors and You

Starting Small: A Quarter Through a Dime-Sized Hole

1. Fold an index card in half, widthwise.
2. Unfold the card and trace a dime so that it is centered on the card. Use the crease as a guideline.
3. Refold the card and cut out the shape of the traced dime.
4. Now that you have a dime-sized hole, try to fit a quarter through it. It's just not possible, right?
5. Here's the trick . . . .  With the card folded along the crease, place the quarter inside of the folded card. Make sure that the quarter is centered on the dime-sized hole you already cut.
6. Grip each of the corners on the folded end of the card with your thumb and index finger. Pull the corners up and watch as the quarter slides out the dime-sized hole.

Going Big: Fitting Through an Index Card

1. Fold an index card in half, lengthwise this time.
2. Unfold the card and cut an incision along the crease that you've created. Don't cut all the way to the either end of the card. Leave 1/8" to 1/4" on each end.
3. Fold the card in half again along the same crease as before.
4. Carefully make a cut at the point your first incision stopped at a 90º angle down towards the open or unfolded side of the card. Again, remember to leave a 1/8" to 1/4" gap.
5. Repeat the previous step, this time starting from the open side of the card, leaving a gap before you get to the other incision.
6. Continue making alternating cuts along the length of the card until you reach the other side.
7. Gently pull the card open by pulling on the two ends of your original crease. The resulting, zig-zagging loop will be big enough to fit over your entire body!

How does it work?

Both of these Index Card Tricks are based on topology. Topology is concerned with continuous deformation of objects and how the way a surface or object is analyzed and manipulated determines how we understand it. Sounds complicated, right? The science of topology shows how you can alter the shape of an object without altering its size.

In the Quarter Through a Dime-Sized Hole experiment, you are able to change the perceived size of the hole without actually altering it. The squeezing and bunching of different areas of the card allow the hole to gain size along the width of the quarter.

In the Fitting Through an Index Card experiment, when you cut the card as the instructions direct you to, you do not remove any part of the card. You simply change the perceived layout in the zig-zagging loop that allows you to fit through it. In both experiments, topology allows you to change the shape or layout, but not the actual size.

SOURCE: Steve Spangler Science

A Recorded Online Physics Class

PHYSICS CLASS

https://sas.elluminate.com/site/external/jwsdetect/playback.jnlp?psid=2011-02-16.0945.M.A5BB78333AC4FEC568A60D2CE9B0FA.vcr&sid=voffice

Chlorophyll, Chromatography, Colors

Of all the natural processes around us, the annual changing of leaves from green to different shades of yellow, orange, and red is perhaps the most beautiful. But behind this show of color, there are important scientific processes at work.

Want a peek into the science behind a tree's changing leaves? With this hands-on activity, you'll see how those colors stay hidden in the leaf all year long!

What You Need:

• Leaves
• small jar (a baby food or small salsa jars work well)
• cover for jars or aluminum foil or plastic wrap
• rubbing alcohol
• paper coffee filter
• shallow pan
• hot tap water
• plastic knife or spoon

What You Do:
 

1) Have your child collect 2-3 large leaves from the same tree type. You and your child should tear or chop the leaves into very small pieces and put them into small jars.  

2) Add enough rubbing alcohol to the jar to cover the leaves. Using a plastic knife or spoon, carefully chop and grind the leaves in the alcohol. 

SAFETY NOTE: rubbing alcohol can be harmful if mishandled or misused. Use in a well-ventilated area, and avoid contact with skin.

 

3) Have your child cover the jar very loosely with a lid, plastic wrap or aluminum foil. Place the jar carefully into a shallow tray containing 1 inch of hot tap water.

 

4) Keep the jar in the water for at least a half-hour, longer if needed, until the alcohol has become colored (the darker the better). 

Twirl the jar gently about every five minutes. Replace the hot water if it cools off.

5) Have your child cut a long thin strip of coffee filter paper. 

Remove the jar from the water and uncover it. Place a strip of filter paper into the jar so that one end is in the alcohol. Bend the other end over the top of the jar and secure it with tape.

The alcohol will travel up the paper, bringing the colors with it. 

 

6) After 30-90 minutes the colors will travel different distances up the paper as the alcohol evaporates. You should be able to see different shades of green, and possibly some yellow, orange or red, depending on the type of leaf.

What happened?

Chlorophyll is a green compound that hides the other colored pigments present in leaves. In the autumn chlorophyll breaks down, allowing the other pigments to be seen. The mix of pigments in a leaf may be separated into bands of color by the technique of paper chromatography.

Chromatography involves the separation of mixtures into individual components, which you just did using alcohol and energy (heat). Then, by "absorption" and "capillarity," separation can take place!
The paper holds the substances using absorption, while capillarity pulls the substances up the paper at different rates. Pigments are separated on the paper and show up as colored streaks or bands.
Pretty cool, huh?

As possible extension activities compare different types of leaves and/or experiment with other types of paper.

By Mike Calhoun and Michael Calhoun

Mike is a 20-year veteran science teacher, and runs an online business (www.scienceinabag.com). Over the years Mike has studied trends in science, education, and finance, conducting research, developing programs, and writing articles on these topics.

SOURCE: Education.com

LAGNIAPPE:  Chlorophyll in Olive Oil

Mysterious Appearing Colors (Benham's Disk)

Video followed by explanation. Source link.

We know that red and blue make purple, blue and yellow make green, and that yellow and red make orange. Most of all, we know that when you mix black and white you get…um…a rainbow. You can use black and white to make actual colors. See just how the spinning illusion can trick your eyes. Materials Printer White paper Craft paper or card stock paper Glue stick Toothpicks Downloadable template Click on the downloadable template and print it out on craft paper or card stock. Cut out one of the four circular designs. Break a toothpick in half and stick one of the halves through the design you cut out. Make sure the pointed end of your toothpick is on the blank side of the disk. You've made a top. Give the top a spin and watch the design on the top. What do you see? Repeat steps 2-4 with the other three circular designs. What do you notice about these designs as they spin? Observations Once you've got the disk spinning, take a look at the circular design on it. What's going on over there? Where did all of those colors come from? *Note* Some of the disks only produce colors at certain speeds, some faster or slower than others. How does it work? Hmmm… how does it work? That's a really good question. We honestly don't know for sure. No one does. But we've got some pretty good guesses. The black and white circular design that you printed out and pasted to your cardboard is called Benham's Disk.  Benham's Disk originated over 100 years ago and, when spun at the right speed, creates a changing pattern of light that is noticeable by your retina.  Many scientists think that the visible pattern of light created by the disk resembles a "code" similar to what the brain receives when the eyes see color. The rapidly spinning black and white disk tricks the brain into seeing the colors. Crazy!

Engineering Ground Zero (NOVA)

Building Green
The new season of NOVA kicks off with Engineering Ground Zero. This month, SPARK explores green energy as it relates to sustainable building. From defining alternative energy to understanding the influence of Mother Nature in building construction, these resources shed light on the direction and future of building innovation.
Join us on Facebook and Twitter, or visit the NOVA Teachers and Teachers' Domain websites to tap a wealth of great STEM-related video clips, animations, interactives, and activities.


Keep investigating!
Rachel Connolly, Director of Education, NOVA

Designing Future Cities: Alternative Energy
Can you design the green city of the future? 
Take on the role of city planner and work out design solutions that incorporate innovative energy alternatives.
Video (2m 11s), Grades 3-8

Physics of Stone Arches  
How do arches stay standing? 
Try your hand at constructing a cathedral arch and learn more about the physics behind the arch.
Interactive, Grades 7-12

Green Technology: Sustaining the Earth
How can technology move us toward a greener future?
Explore areas of research and innovation in green technology: renewable energy and conservation; green building; transportation; manufacturing; and pollution and waste management. 
Interactive, Grades 6-12

The Structure of MetalWhat makes metal special?
Explore metal at the atomic level and find out what makes it such a versatile material.
Interactive, Grades 6-12

Nature's Super Materials
How is Mother Nature inspiring the next generation of strong materials?
See some of the amazing structures and properties that animals and plants have evolved, and learn about new human-made super-materials they are giving rise to.
Interactive, Grades 6-12

It's Elemental (with example worksheet)

Whether they are created by nature or in the lab, chemical substances are all made of some combination of just 118 pure elements.

These elements come together to produce an amazing diversity of materials. In this interactive, discover which elements are most abundant in the universe, the sun, and the Earth as well as in the human body and in that flashiest of human creations—fireworks.

Also, learn which elements have the most extreme properties on the periodic table.

 

Launch Interactive 

 

Download

  In this interactive periodic table, explore the elements and their properties and abundances.

A previous version of this feature originally appeared on the site for the NOVA program Kaboom!.

EXAMPLE WORKSHEET (with answers)

Elements of the SUN

 Pablo Cortez  IHM

8-31-11 Wednesday

1st most abundant element of the SUN: Hydrogen
Symbol: H
Family: Alkali metals

2nd most abundant element of the SUN: Helium
Symbol: He
Family: Noble gasses

3rd most abundant element of the SUN: Oxygen
Symbol: O
Family: Nonmetals

4th most abundant element of the SUN: Carbon
Symbol: C
Family: Nonmetals

5th most abundant element of the SUN:  Nitrogen
Symbol: N
Family: Nonmetals

6th most abundant element of the SUN: Neon
Symbol: Ne
Family: Noble gasses

7th most abundant element of the SUN: Iron
Symbol: Fe
Family: Transition metals

8th most abundant element of the SUN: Silicon
Symbol: Si
Family: Nonmetals

9th most abundant element of the SUN: Magnesium
Symbol:  Mg
Family: Alkaline earth metals

10th most abundant element of the SUN: Sulfer
Symbol: S
Family: Nonmetals

 

Sources:

NOVA:  http://www.pbs.org/wgbh/nova/physics/periodic-table.html 

Data provided by PeriodicTable.com. Melting point, boiling point, and density data apply to elements at standard atmospheric pressure.