Celebrate National Read Across America Day With Oobleck

Dr. Seuss is considered by many to be one of the most successful children's books writers of all time.  He published his first book, And to Think That I Saw It on Mulberry Street, in 1937.  Between that time and his death in 1991, he published more than 40 books and sold half a billion copes.   Because of his profound influence on children and their love of reading, the National Education Association has adopted Dr. Seuss' birthday, March 2, as National Read Across America Day.   

One of my favorite science investigations builds on one of the good doctor's fantastic books...Bartholomew and the Oobleck (1949).  The book (the sequel to The 500 Hats of Bartholomew Cubbins), follows the adventures of Bartholomew Cubbins, royal page in the kingdom of Didd, as he attempts to clean up the mess created by King Derwin when the king orders his royal magicians to cause an extremely sticky green substance known as Oobleck to rain from the sky. The story is great. But making Oobleck...that's amazing! In today's Science Wondershop, we'll teach the secret behind making your own Oobleck with some simple materials you can find right in your home.  I must warn you, however, making Oobleck is an educational and extremely messy experience!

Here’s What You Need

•     Corn Starch
•     A Bowl
•     Water
•     Food coloring (optional)

How's that for a list of materials. It can't get much simpler than corn starch and water.

Here’s What You Do

In your bowl, slowly add the water to the corn starch (you may want to color the water green...for added effect). You want a mixture that is about 1 part water and 2 parts cornstarch.  Stop when the corn starch/water mixture is thick and gooey. Remember, you're making Oobleck...not gravy.

That's it. One step. Pretty simple, huh? Now it is time to explore the properties of this really interesting material.  As you explore the Oobleck, think about these questions:

• Can you pour Oobleck?
• What happens when you hold it in your hand?
• What happens if you poke it with your finger (quickly or slowly)?
• Can you roll it into a ball?
• Is it a solid or a liquid?
• What happens if you smack the top of the Oobleck with your hand?

Clean Up: Oobleck will clog pipes so don’t pour it in the sink! If you have a dumpster or large trash can, dispose of it there. If it gets on the floor or carpet, don't worry. Once it dries, it vacuums or sweeps up easily. You can also save containers of Oobleck by covering them with plastic wrap and putting them in the refrigerator.

The Science Behind Oobleck

Is Oobleck a solid or a liquid? Maybe it is a solid and a liquid. Impossible. It can't be both. The truth...Oobleck is a non-Newtonian fluid. Most of the fluids we know are Newtonian fluids, but non-Newtonian fluids are a weird but interesting group of fluids. When a force (e.g. sqeezing, stirring, slapping) is applied to a non-Newtonian fluid, the viscosity (resistance to flow) of the fluid increases. In simple terms, any force you exert on a non-Newtonian fluid will make the fluid behave more like a solid. The more force you exert, the harder the fluid becomes. Strange but true! Other types of non-Newtonian fluids include quicksand, ketchup, and blood.

Wondershop Fast Facts: Dr. Seuss

Here are some interesting things you might not know about Dr. Seuss:

• His real name was Theodore Seuss Geisel - Seuss being his mother's maiden name. He started using it as a pseudonym at university. He added the Dr later, as a joke, because his father had always wanted him to get a doctorate and become a professor.

• Between 1937 and 1991, when he died aged 87, he published more than 40 books, which have sold half a billion copies between them - more even than J K Rowling's Harry Potter books. He nearly burned his first book, And to Think That I Saw It on Mulberry Street, after it was turned down by 27 publishers. 

• One of his most popular books, Green Eggs and Ham, was the result of a bet that he could not write a book using only 50 words.

 Source: BBC News (news.bbc.co.uk/2/hi/europe/3523393.stm)

This Year, Charm Your Valentine With Science

You've done chocolate.  You've done cards.  You've even done the candlelit dinner.  Now, you find yourself searching for something really special to really charm your valentine this year.  How about a little science?  That's right...with a little preparation, some simple materials, and some science know-how you will have your special someone swooning. At the very least, they'll be impressed.  This year, send them a secret message that can only be revealed with a little...heat!  

Here's What You Need

• A Frixion Pen (blue or black works best)
• A regular ball point pen (the same color as your Frixion Pen)
• A Valentine's Day card, a notecard, or something else to write you message on
• A candle, lighter, or toaster

Here's What You Do
Use the regular ball point pen to write your secret Valentines Day message on your card.  Remember, this will only be read by your sweetheart, so don't worry about being too mushy. Really pour on the sap!

Use the regular pen to write your secret Valentines Day message

Now, use the Frixion Pen to disguise your secret message.  The object is to make the message impossible to read.  Turn the letters into symbols.  Write new letters or words.  Draw flowers, trees, birds, and little stick people.  Get creative!  Remember, you are sending  a secret message.  The object is to hide your message with the Frixion Pen.

Use the Frixion Pen to disguise your letters and words

When you give your card to your special someone, they will probably be uncertain about what they see. Take advantage of this moment of utter confusion. Wave the card over a heat source such as a candle, lighter, or toaster.  Anything that was written with the Frixion pen will quickly disappear when the writing is expose to heat. All that will remain is the message you wrote with the regular ball point pen!  Now smile and soak up all that good Valentines Day lovin'!

Heat will cause the Frixion pen ink to disappear

The Science Behind the Disappearing Ink
The Frixion Pen is not like other erasable pens. The ink in these pens is sensitive to changes in temperature.  At temperatures between 15°F and 140°F, the ink will appear black or blue on the paper.  However, as the temperature goes above 140°F the ink becomes clear.  Holding your card over the open flame pushed the temperature past that 140°F mark.  Likewise, if you want the pigment to reappear you need to cool the ink down to a temperature lower than 15°F.  Stick your card in the freezer for a while and the symbols you created should reappear!
Because it responds to changes in temperature, the ink in the Frixion Pen is known as thermochromatic ink. It can be formulated to change colors at different temperatures. These types of pigments have been around for quite a while.  In fact, they are responsible for the color changes in things like mood rings and heat sensitive labels. 

Happy Valentines Day from the Science Wondershop

Here's a little Valentines Day science for you. Concentrate on the text in the center of the image - You're Cool (focus in...don’t blur your vision!).  After a little while, the hearts will disappear! Don't believe it? Try it.  Another side effect is that the missing rotating heart will turn blue.  Pretty amazing, huh? This animation was created by Mr. Scott Henderson! 

How Does This Work
The hearts disappear due to an effect know as retinal fatigue.  The retina is the part of the eye that is sensitive to light.  It acts like a camera.  Images that come through the lens of the eye are focused on the retina.  The retina turns the image into a signal that it sends to the brain. Objects like these hearts, which are moving constantly in a repetitive motion, are basically ignored by the brain after a little while.  This causes them to disappear from view.

Now let's explore whey you see the blue heart.  An afterimage is a visual impression of an image that remains in the retina of the eye after the initial image is removed. The afterimage always has colors that are complementary to those of the original image.In this case the after image is a blue heart! 

By studying visual illusions, and the ways in which the brain controls what we perceive, scientists learn more about sensory perception, about the brain, and about vision.

Looks Like an Early Spring...According to the Groundhog

It’s February 2nd!  You know what that means…Groundhog Day! If you are not familiar with this particular observance, this is how the whole thing works. Early in the morning on Februay 2nd, people gather around the burrow of a Marmota monax; a large rodent also known as the whistle pig, eastern marmot, southern marmot, monk, woodchuck, or groundhog. It is believed that if the groundhog sees its shadow when it climbs out of the burrow, there will be six more weeks of cold, wintery weather. On the other hand, if it doesn’t see its shadow, the warmth of spring will arrive soon. Here’s an additional little nugget to impress your friends with today: Groundhog Day is a cross-quarter day. That means it fall halfway between the Winter Solstice and Vernal Equinox.


There are a number of cities that host their own Groundhog Day celebrations…complete with their own groundhogs. Here are some of the results from this year:

• Punxsutawney Phil (Punxsutawney, Pennsylvania): Early Spring
• Jimmy the Groundhog (Sun Prairie, Wisconsin): Early Spring 
• Wiarton Willie (Wiarton, Ontario): Early Spring 
• French Creek Freddie (French Creek, West Virginia): Early Spring
  
• General Beauregard Lee (Lilburn, Georgia): Six more weeks of winter
• Chuckles (Manchester, Connecticut): Six more weeks of winter
• Dunkirk Dave (Dunkirk, New York): Early Spring 
• Gus (Athens, GA): Early Spring
• Buckeye Chuck (Marion, Ohio): Early Spring 
• Sir Walter Wally (Raleigh, North Carolina): Six more weeks of winter
• Grady the Groundhog (Chimney Rock, North Carolina): Six more weeks of winter
  
• Staten Island Chuck (Staten Island, New York): Early Spring 
• Woody (Howell, Michigan): Early Spring

Is there any science behind this whole Groundhog Day thing?
I did a bit of research and this is what I found out. Historically, people have observed animal behavior for clues to changes in the weather. For example, geese flying south is a sign of the coming of fall for many people living in the United States. The reappearance of hibernating or inactive animals is a sign of winter’s end. When German settlers came to Pennsylvania in the 1700s, they selected the groundhog as their seasonal forecaster.

There may also be a meteorological explanation for groundhog day. It is thought that the observance may have roots in a weather phenomenon described in the Scottish poem below:

If Candlemas Day is bright and clear,
There’ll be two winters in the year.

The idea behind this poem can be found in cultures around the world. In the poem, Candlemas Day refers to February 2nd…Groundhog Day. Farmers in ancient Europe noticed that bright, clear winter days are often very cold. We now know that this is caused by high pressure systems. Areas of high pressure pull cold air down from the north. They also sweep away any clouds that might have provided insulation. Consequently, a bright winter day (one on which a groundhog may see a shadow) may be an indication of more cold days to come.

Of course, none of this is sound evidence that groundhog can actually predict the coming of spring. Instead, Groundhog Day can be seen as a celebration of the role of scientific observation and prediction in our world. Every day, we make observations about the world around us, attempt to make meaning of those observations, and create predictions about the way things will happen in the future. Groundhog Day is wonderful example of this. Over the course of time, we have combined our observations of animal behavior and weather to create a system for predicting spring. Does it work? Well, that is a question I will leave to you and your children to explore.