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Serpent Skin™ Tubing NGSS

SKU #SM-200
Availability: In Stock
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A hassle-free alternative to dialysis tubing.
~12m length

Description

Serpent Skin tubing is similar to dialysis tubing, except that it is far less expensive. It simulates a cell wall or cell membrane. The microscopic pores in the cellulose tubing produce a physical selection barrier - a semipermeable membrane. These microscopic holes provide a passageway for small molecules to diffuse through the membrane while blocking the diffusion of larger molecules. Serpent Skin may be used either wet or dry. The equilibrium of particles moving through the membrane can be measured by changes in concentration, osmotic pressure, color, volume, or mass. The activities and experiments you can create with this fantastic teaching tool are only limited by your imagination. A sheet of ideas and experiments is included with every order. Sold in 12 meter lengths.

Read more on our Blog!

Lesson Ideas

Download the pdf of this lesson!

Instructions by John W. Fedors

Crinkled Dialysis Tubing

Dialysis tubing can be used to simulate cell walls/cell membranes. The microscopic pores provide a passageway for select sized molecules to diffuse from a greater to a lesser concentration; passive transport of larger molecules is inhibited. Yes, you have a semipermeable membrane. Water and other small molecules have the ability to diffuse both ways and to establish an equilibrium. The equilibrium may be measured by changes in: concentrations, osmotic pressure, color, volume, and mass. Activities can be designed to be specific or a combination of these changes.

The use of 'Serpent Skin' provides tubing which is much easier to use than dialysis tubing. The usual dialysis tubing is flat and has to be wet to use. The open tubing makes it easier to fill with a variety of materials, especially dry.

The activities which you can develop using 'Serpent Skin' is limited only by your comfort level of exploration. The expense of teacher/student designed explorations may also be a challenge.

Exploration Purpose: Demonstration of Water Pressure

Materials:

  • Serpent skin
  • Scissors
  • Wire twists
  • Clear Plastic Cups with Caps
  • Thread
  • Funnel
  • Straws
  • Soil Moist
  • Seeds
  • Oat Bran
  • 5-Grain Hot Cereal

Procedure:

  1. Pull a section of Serpent Skin and make a knot, then cut off a section.
  2. Stuff tubing, toward knotted end, with material.
  3. Insert clear straw in open end and secure tubing onto straw.
  4. Place entire apparatus in cup with water.
  5. Repeat with other material.
  6. Record your observations.

In But Not Out
Water Molecules Pass Through a Variety of Membranes

Hypothesis:

There are conditions in nature which retain water and build pressure on membranes.

Purpose:

Design an exploration that may demonstrate how water molecules may be collected in a porous container and be kept there.

Materials:

  • Serpent Skin
  • Soil Moist (Crosslinked Polyacrylamide)
  • String
  • Scissors
  • Plastic Cup
  • Scale or Balance
  • Measuring Tape

Procedure: (This is how it might be set up)

  1. Measure out a 6-inch piece of Serpent Skin and tie one end off.
  2. Place 10 grams of soil moist into the tube made from the Serpent Skin.
  3. Seal opening and measure length, circumference, and mass of tubing.
  4. Place your sealed tubing into a beaker containing water.
  5. Record all of your measurements.
  6. Make observations every 15 minutes and record.
  7. Graph your results, demonstrating the changes that have taken place over a period of time.

Discussion:

  1. Crosslinked Polyacrylamide is capable of absorbing many times its weight in water.
  2. When placed in a dry environment, the water is released.
  3. The Serpent Skin permits water to go both ways, why is not evident during the exploration.
  4. Variables might be suggested to increase the speed of water uptake.

Water Rock Volcano
Serpent Skin is Forced to Erupt Water Rocks

Hypothesis:

Water pressure may force larger molecules to erupt through a designed opening.

Purpose:

Design an exploration that will demonstrate water pressure on crosslinked polyacrylamide.

Materials:

  • Serpent Skin
  • Soil Moist
  • String
  • Scissors
  • Tall Plastic Cup with Plastic Cover
  • Clear Straws
  • Spoon

Procedure: (This is how it might be set up)

  1. Measure out a 6-inch piece of Serpent Skin and tie one end off.
  2. Place 20 grams of soil moist into the Serpent Skin tube.
  3. Place straw into open end, about 1/2-inch in., and tie tubing securely around straw.
  4. Push straw through center of cover.
  5. Place your sealed tubing with protruding straw in tall cup containing water.
  6. Record your observations
  7. Graph your results, recording height attained in straw and amount of erupted water rocks.

Discussion:

  1. Soil Moist is capable of absorbing an enormous amount of water.
  2. As Soil Moist erupts, it loses moisture.
  3. Using a longer or shorter straw might be something to consider.
  4. Covering straw with gauze before inserting into open end might prove interesting.

Slow Iodine Clock
Molecules Vary in Size and Larger Molecules are Easier to Contain

Hypothesis:

A solution containing iodine molecules can be used to demonstrate that they are constantly moving to attain equilibrium.

Purpose:

Design an exploration that will demonstrate the movement of iodine molecules from an area of higher concentration to one of lower concentration.

Materials:

  • Serpent Skin
  • 1% Aqueous Solution of Iodine
  • 1% Soluble Starch Solution
  • String or Twist-Tie
  • Scissors
  • Clear Plastic Cup
  • Funnel (optional)

Procedure: (This is how it might be set up)

  1. Measure out a 6-inch section of Serpent Skin and tie one end off.
  2. Place 10 ml of starch solution into the Serpent Skin tube.
  3. Seal open end and rinse off outside of tubing.
  4. Place water in beaker and add enough iodine solution to color the water.
  5. Place rinsed tubing containing starch solution into iodine colored water and make your observations.
  6. Graph your result demonstrating the changes that have taken place over a period of time.

Discussion:

  1. Serpent Skin is selective, for it permits small molecules to pass through, but not larger ones.
  2. The iodine molecules attach to the starch molecules.
  3. Starch molecules are not permitted to pass out through the dialysis tubing.
  4. Place the entire, still sealed, tubing into hot water and make a new hypothesis.

In, Up, and Out
Serpent Skin is Selective to Concentrations

Hypothesis:

The less concentrated a water solution, the less solute, the quicker it moves toward higher concentrations and more solute.

Purpose:

Design an exploration that will demonstrate movement of both solvent and solute through membranes at different rates.

Materials:

  • Serpent Skin
  • String
  • Scissors
  • Clear 'Karo' Syrup
  • Tall Plastic Cup with Plastic Cover
  • Clear Straws
  • Funnel
  • Red Food Dye
  • Ruler

Procedure: (This is how it might be set up)

  1. Measure out a 6-inch piece of Serpent Skin and tie one end off.
  2. Place 20 ml of clear Karo syrup into tubing.
  3. Place clear straw into open end, about 1/2-inch in, and tie tubing securely around straw.
  4. Rinse off the outside of the tubing.
  5. Push straw through center of cover. Rinse off any spills.
  6. Place your sealed tubing with protruding straw in tall cup containing water.
  7. Record your observations.
  8. Graph your results, recording height attained in straw.
  9. Graph and predict when level will completely disappear from straw.

Discussion:

  1. How might you determine if Karo came out of the Serpent Skin?
  2. What happened to the color in the clear straw?
  3. What can you predict about the differences in size of molecules that are capable of passing through the Serpent Skin?
  4. If you had Soil Moist in the Serpent Skin, and red dyed Karo syrup outside, what might you hypothesize?

Hassle-Free (crinkled dialysis tubing) simulates a cell wall/membrane. The microscopic pores in the cellulose tubing produce a physical selection barrier, a semipermeable membrane. The microscopic pores provide a passageway for select-sized molecules to diffuse from a greater to a lesser concentration and inhibit larger molecules from diffusing. Water and small molecules have the ability to diffuse both ways and to establish a concentration equilibrium.

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Reviews

7 reviews
Kendra
Review star icon Review star icon Review star icon Review star icon Review star icon May 18, 2017
We LOVE this product. Rather than tie the ends, we use clamps (from a different vendor). The students can easily fill the tubing when it is dry, as it stays open easily. There are very few problems with leaks. And the serpent skin is cost effective.
Kendra Norman

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A.P. Biology
Review star icon Review star icon Review star icon Review star icon Review star icon Oct 4, 2016
I use this product in both biology and A.P. instead of normal dialysis tubing. It is amazing. You can tie knots in it with ease, and create many different types of labs to model diffusion and osmosis/water potential. The cost is much less than actual dialysis tubing, and typically one tube will work for my 5 classes of 35 students.
Jake

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Excellent!
Review star icon Review star icon Review star icon Review star icon Review star icon Sep 5, 2015
great product, very service. One very satisfied customer!
charles howard

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Serpent Skin Saves!
Review star icon Review star icon Review star icon Review star icon Review star icon May 4, 2015
This cellulose tubing has saved our school science lab hundreds of dollars in expensive dialysis tubing for diffusion/osmosis labs.
B.Wise

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Serpent skin holely
Review star icon Review star icon Review star icon Review star icon Review star icon Oct 24, 2013
Had to throw a about a foot and had to inspect it for other holes. Still less expensive than dialysis tubing
Peter A Lauzon
Owner Response: I'm sorry, Peter! I don't think we've ever had this problem before. I'm wondering if somehow your product was damaged on one side. We are happy to replace the Serpent Skin. Someone from Customer Service will contact you.

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Great for science club!
Review star icon Review star icon Review star icon Review star icon Review star icon Nov 8, 2012
I love how a little of this goes a long way! We used 3-4 inches of this per science club student (elementary) to explore food transport through the wall of the intestines. We used molasses and/or colored corn syrup inside the serpent skin and water in a cup. The children were able to observe the transfer of sugar and water. Then reverse the process by putting their "gut" into a cup of corn syrup! Plastic Wire ties made closing the serpent skin easy for small hands.
Ann Jansen

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Works Great, but Cost Prohibitive
Review star icon Review star icon Review star icon Review star icon Review star icon May 16, 2012
I received a sample of this product at a CAST conference. When I used it in my classroom I loved it! Made setting up transport labs super easy!!! Unfortunately, when I went online to order more, I saw the price. Way to expensive for the amount on a "roll" if you are trying to outfit an entire set of high school classes. This is especially true if you have to pay out of pocket. Until the price becomes obtainable, I will stick with the old school dialysis tubing on a roll. It's cheaper per foot. Soaking overnight and opening tubing beats convenience when $$ is involved! ...................................................................................................................................... ....................................**Educational Innovations Responds**................................... ...................................................................................................................................... Mary, I did a little research and found that our competitors' brand of dialysis tubing is actually much more expensive than our Serpent Skin Tubing. We offer 12 meters for $14.95, and according to my math, that's about 1/3 the cost of of normal dialysis tubing. I hope you will reconsider this product since it will save you both time and money.
Mary

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NGSS

This product will support your students' understanding of the Next Generation Science Standards (NGSS)*, as shown in the table below.

Elementary Middle School High School

2-PS1-1

Students can use Serpent Skin in an investigation to describe and classify different kinds of materials by their observable properties.

5-PS1-1

Students can use Serpent Skin in an investigation to develop a model to describe that matter is made of particles too small to be seen without magnification.

MS-PS1-1

Students can use Serpent Skin in an investigation to develop models to describe the atomic composition of simple molecules and extended structures.

MS-LS1-1

Students can use Serpent Skin to conduct an investigation to provide evidence that living things are made of cells, either one cell or many different numbers and types of cells.

MS-LS1-2

Students can use Serpent Skin to develop and use a model to describe the function of a cell as a whole and ways parts of cells contribute to the function.

MS-LS1-3

Students can use Serpent Skin as part of the evidence to support an argument for how the body is a system of interacting subsystems composed of groups of cells.

MS-LS1-4

Students can use Serpent Skin as part of an investigation to gather and synthesize information that sensory receptors respond to stimuli by sending messages to the brain for immediate behavior or storage as memories.

HS-PS1-1

Students can use Serpent Skin in an investigation to predict properties of elements. Students can use the Periodic Table as a model to predict the relative properties of elements based on the patterns of electrons in the outermost energy level of atoms.

HS-PS2-6

Students can use Serpent Skin in an investigation to communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials.

HS-LS1-1

Students can use Serpent Skin to construct an explanation and models of cells based on evidence for how the structure of DNA determines the structure of proteins that carry out the essential functions of life through systems of specialized cells.

HS-LS1-2

Students can use Serpent Skin to develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions with multicellular organisms.

HS-LS1-5

Students can use Serpent Skin to develop a model to illustrate how photosynthesis transforms light energy into stored chemical energy.

Suggested Science Idea(s)

2-PS1-1
5-PS1-1
MS-PS1-1
HS-PS1-1
HS-PS2-6
MS-PS1-1

Students can use Serpent Skin in an investigation to see density in action. The heat sensitive material is a polymer.

K-2-ETS1-2

Students can draw on Serpent Skin during an investigation to illustrate how the shape of an object helps it function as needed to solve a given problem.

 

* NGSS is a registered trademark of Achieve. Neither Achieve nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of, and do not endorse, this product.

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