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Sand to Nuts

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TEACHING GUIDES


Life's Little Questions:
Sand to Nuts


Footprints on the beach, a can of mixed nuts, sand in an hourglass and coffee spilled on kitchen counters may not seem like critical topics for study, but these same subjects have led scientists to some fascinating explorations into materials science. In this story, watch as seemingly trivial questions lead curious scientists into inspired investigations about much bigger issues.

Curriculum Links
National Science Education Standards
Related Frontiers Show and Activity
Activity 1: Lessons Learned from Coffee
Activity 2: Materials Science




CURRICULUM LINKS


CHEMISTRY


 

MATERIALS
SCIENCE

 

PHYSICAL
SCIENCE/PHYSICS

granular particles

TECHNOLOGY


 




NATIONAL SCIENCE EDUCATION STANDARDS

SCIENCE AS INQUIRY / PHYSICAL SCIENCE
5-8: Properties and Changes of Properties in Matter; Structure and Properties of Matter
SCIENCE AND TECHNOLOGY
5-8,
9-12:
Abilities of Technological Design, Understandings About Science and Technology
SCIENCE IN PERSONAL AND SOCIAL PERSPECTIVES
5-8: Science and Technology in Society
9-12: Science and Technology in Local, National and Global Challenges
HISTORY AND NATURE OF SCIENCE
5-8: Science as a Human Endeavor, Nature of Science, History of Science
9-12: Science as a Human Endeavor, Nature of Scientific Knowledge, Historical Perspectives




RELATED FRONTIERS SHOW AND ACTIVITY

  • Science in Paradise: (Show 901): Big Dish


ACTIVITY 1: LESSONS LEARNED FROM COFFEE

As you see in this episode of Frontiers, seemingly insignificant questions sometimes lead to complex answers -- and to other questions.

Physicist Sidney Nagel of the Materials Center at the University of Chicago began his investigation by wondering about something we've all seen many times -- coffee stains on a kitchen counter. His questions about why the stains form as they do became almost an obsession with scientists from several fields. Watch the program to find out what they discovered. Then try this simple experiment to learn more.


MATERIALS

  • powdered tempera paints or other water colors (light colors work best)
  • various liquids: coffee, salt water, tap water, soda, juice, Tang, tea, cocoa
  • plastic lids from butter tubs, coffee cans, etc.
  • paper, cloth and/or a flat, washable surface
PROCEDURE

  1. Mix the paint and any of the powdered drink mixes with water according to package directions.

  2. Place several drops of paint and of each liquid onto paper, cloth or a flat surface.

  3. Watch as the drops dry.

  4. Write down your observations of the phenomenon. Note what changes occur every five minutes.

Now introduce some variables:

  1. Place a few drops on paper and let it dry upside down. What happens?

  2. Use plastic lids as covers to manipulate the evaporation of liquids. Make covers that will:
    • Completely cover the drop. What happens?
    • Cover the edges of the drop but expose the center. What happens?
    • Cover half of the drop and leave the other half exposed. What happens?
QUESTIONS
  1. Which liquid(s) developed the most distinct ring(s)? The least? Why?

  2. How did the rate of evaporation play a role in the formation of the ring?

  3. How did the surface beneath the drops (paper or countertop) affect the rate of evaporation and the development of the deposition ring?
EXTENSIONS

  • Try the above experiment on pieces of paper with different textures: computer or notebook paper, construction paper or homemade recycled, paper towel, coffee filters, etc. Compare the results achieved by using these different surfaces.

  • Compare stains left by coffee made using different methods -- instant, filtered, espresso, cappuccino. What accounts for the differences?

  • Watch a drop of coffee evaporate through a microscope. Explain what you see happening as the liquid evaporates.

  • Look up the chemical composition of caffeine and sketch an illustration.
ANSWERS

  1. liquids that are partially wetting and volatile should cause rings (coffee, Kool-Aid, salt water, soda)
  2. as the liquid evaporates from the drop, molecules of evaporating liquid continually replenish the exterior of the stain
  3. answers will vary


ACTIVITY 2: MATERIALS SCIENCE

Physicists Sidney Nagel and Heinrich Jaeger have made careers out of studying properties and behavior of various materials. As you see on Frontiers, their work sometimes takes them in unexpected directions. Try replicating some of the experiments you see on the program. What do you observe?

  • Next time you're on a beach, see if you can create a "halo" effect with your feet.

  • Put some sand and water in a squeeze bottle. Do you get the same results seen on the show?

  • Find a clear plastic tube. Put some sand and a small ball in it. Can you get the ball to climb to the top of the tube? Can your friends do it? (Try testing people who haven't watched this episode of Frontiers.)

  • Obtain a can of mixed nuts. How are the nuts mixed when the can is first opened? Shake the can. How do the nuts mix or unmix? Do you think it would be possible to design a can that keeps the nuts evenly mixed? Explain. (Hint: if nuts are shaken many times, the walls of the can become so smooth that the nuts will no longer unmix. Friction is one key.)

  • You can learn more about the experiments with coffee and other materials at the Materials Center of the University of Chicago. You'll also learn more about practical applications of these findings. To learn more, visit: mrsec.uchicago.edu/MRSEC/





 

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