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Fullerene paper models

Photo of finished C60 and C70 fullerene models

Age: Any

Background: The "buckyball" is a cage-like nanoscale structure made of 60 carbon atoms. It is sometimes also called C60, because C is the symbol for carbon, and there are 60 carbon atoms. If you could see an actual buckyball (it's too small to see with an optical microscope), you would find that its shape resembles the geodesic domes popularized by the architect and inventor, R. Buckminster "Bucky" Fuller—hence its full name: buckminsterfullerene. The buckyball was first made in the laboratory in 1985 by Robert F. Curl, Jr., Sir Harold Kroto, and Richard E. Smalley. They won the Nobel Prize in Chemistry in 1996 for their discovery! Since then, buckyballs have been found in nature—in space around dying stars, in soot, in meteors, in material hit by lightening strikes, and in rock that is roughly 1.8 billion years old!

What you will do: The buckyball is just one in a family of cage-like molecules called fullerenes. In this activity you make paper models of the two most abundant fullerenes, C60 and C70.

Supplies:


Instructions: First, try to take a piece of paper, and tape it together to form a hollow ball like a balloon. Can you do it? Then follow directions on the patterns to create C60 and C70 models.

Consider this:
In these paper models, imagine that there is a carbon atom where lines meet each other (intersect), and each line represents a bond (attractive force) between the carbon atoms. Try to answer these questions about your paper models.

  1. Is it possible to make a ball-like shape from the pattern without cutting out any of the hexagons?
  2. How does removing hexagons and overlapping the remaining hexagons to form pentagon-holes make it easier to build a ball-like shape?
  3. What sport plays with a ball that resembles the C60 model?
  4. How many pentagon-holes did you make on the C60 model? Does the C70 model have the same number of pentagon-holes?
  5. How many hexagons are formed in your finished C60 model (count overlapped hexagons as ONE hexagon)? Does the C70 model have the same number of hexagons?

Discussion:
It would be hard to make a ballon-like ball from a single piece of paper, but after you remove all of the gray hexagons and start overlapping the remaining hexagons, the model starts to curve into a ball! Just like your paper model, you couldn't fold a sheet of graphene, a flat layer of carbon atoms, into a buckyball without rearranging the bonds. The buckyball fullerene, C60, looks like a black-and-white soccerball, while the C70 fullerene resembles a rugby ball - a slightly flattened ball. Both the C60 and C70 (like all fullerenes) have 12 pentagons, while the C60 has 20 hexagons and the C70 has 25 hexagons.

Once you've finished examining the structure of the models, print out a new pattern and decorate it for your very own fullerene work of art. Can you decorate only the hexagons that will be visible in your finished model?

Parents

You may need to help your child cut, fold, and glue the paper models together. Counting the hexagons can easily be done by writing numbers on the hexagons of the finished model. The pentagons are harder because they are holes on the model. Your child could tape across the pentagons they have already counted, or stick all of their fingers in the holes, and then count the two that remain. The C60 pattern will have a spherical shape with 20 white hexagons and 12 pentagon holes. The C70 pattern will have a flattened spherical shape with 25 hexagons and 12 pentagon holes. The word fullerene is used to describe a whole family of hollow cages of carbon molecules with the composition C20+2m, where the bonds form 12 pentagons and m hexagons. The next most abundant fullerene after C60 is C70; The smallest fullerene is C20; its bonds form 12 pentagons and no hexagons.

If your child has trouble deciding which hexagons to color for their own fullerene artwork, remind them how many hexagons they determined were in each structure. You can also show them a more colorful version of the patterns as a guide: C60 Pattern Colored or C70 Pattern Colored

Reference: Based on patterns from Beaton, J. M., A Paper-Pattern System for the Construction of Fullerene Molecular Models. Journal of Chemical Education 1992, 69 (8), 610-612.

Developed by:
Angela Jones, Ph.D.
Institute for Chemical Education and the Nanoscale Science and Engineering Center
University of Wisconsin – Madison

Extracting fullerenes from fullerene soot

Age: This activity is most appropriate for a high school science class rather than a take home project.

Background:In 1996, Robert F. Curl, Jr., Sir Harold Kroto, and Richard E. Smalley were awarded the Nobel Prize in Chemistry for isolating fullerenes, cage-like molecules made entirely of carbon. In 1990, scientists Donald Huffmann of the University of Arizona and Wolfgang Krätschmer of Max Planck Institute for Nuclear Physics and their co-workers devised a way to produce fullerene soot in sufficient enough quantities to measure using spectroscopy. In this activity students perform similar experiments to those of the Huffmann and Krätschmer to extract the two most abundant fullerenes, C60 and C70, from fullerene soot and examine their samples using a spectrophotometer. The instructor's preparation and background description as well as a student's worksheet are included in linked activity sheet. [ExtractingFullerenesActivity.pdf]

Developed by:
Angela Jones, Ph.D.
Institute for Chemical Education and the Nanoscale Science and Engineering Center
University of Wisconsin – Madison

Carbon Nanotube Models

Photo of finished carbon nanotube models


Age: All

Background: A carbon nanotube is shaped like a very long soda straw. The walls of the straw look like one or more graphene sheets rolled into a cylinder, similar to the way you could roll a chicken-wire fence into a cylinder, though carbon nanotubes are not made from sheets of graphene, but rather they are grown along the length of the tube.

What you will do: In this activity, you get to make models of different types of carbon nanotubes.

Supplies:

  • Carbon nanotube model printed on transparency paper (can buy at any office supply store - be sure to get the kind appropriate for your printer: inkjet or laser) [CNT_transparency.pdf]

Instructions: A carbon nanotube made of just one layer of carbon atoms is called a single-walled carbon nanotube (SWCNT). SWCNTs can have three different types of structure: zig-zag, armchair, and chiral. The structures differ in the direction in which it appears a graphene sheet is rolled to make the nanotube.

  1. Cut off the logos in the bottom of the pattern along the dotted line.
  2. Roll the model so that all of the red dots over lap. This is what a zig-zag carbon nanotube looks like. You can tell because the carbon atoms along the top of the tube form a zig-zag pattern around the circumference (outer surface) of the tube.
  3. Roll the model so that all of the blue dots over lap. This is what an armchair carbon nanotube looks like. You can tell because the carbon atoms along the top of the tube look kind of like the front of many connected armchairs (the "arms" are high and the "seat cusion" is low) around the circumference of the tube.
  4. If you roll up the model somewhere in between - not overlapping all of the blue dots or red dots - you form a what is called a chiral carbon nanotube.

Consider this:

Different properties are associated with the different structures: armchair nanotubes are metallic conductors which means they conduct electricity as well as or better than metals; zig-zag and chiral nanotubes can be metallic conductors or semiconductors depending on their diameter (width) and chirality (the tube symmetry). What can you do to make the diameter of the different models bigger or smaller?

Additional information for older kids:

Scientists distinguish between the different types of carbon nanotubes by naming the carbon nanotubes as (n, m) nanotubes, where the indices "n" and "m" indicate how the carbon nanotube is "rolled". The following figures show the distinction. A zig-zag carbon nanotube has indices of (n, 0), where n is the number of carbon atoms along the circumference of the carbon nanotube as shown. An armchair carbon nanotube has indices (n, n) where n is counted as shown in the following figure. In a chiral carbon nanotube the indices are not equal (n and m are different).

If the following figures were wrapped such that the red carbon atoms overlapped, they would be a zig-zag, armchair, and chiral nanotube, respectively.

Example of counting zig-zag carbon nanotube carbons

Zig-zag: (4, 0) nanotube

Example of counting armchair carbon nanotube carbons

Armchair: (2, 2) nanotube

Example of counting chiral carbon nanotube carbons

Chiral: (4, 2) nanotube

Questions

  1. Can you give the name for the armchair carbon nanotube model?
  2. Can you give the name for the zig-zag carbon nanotube model?
  3. Can you give the name the chiral carbon nanotube model you made?
Parents

The armchair carbon nanotube is a (6,6) nanotube.
The zig-zag carbon nanotube is a (13,0) nanotube.
The name of the chiral nanotube will depend on how your child rolls up the tube!

Developed by:
Angela Jones, Ph.D.
Institute for Chemical Education and the Nanoscale Science and Engineering Center
University of Wisconsin – Madison

Superhero Signal

Photo of the Superhero Signal setup

Age: If using a multimeter to determine the resistivity of the pencils, this might be more appropriate for high school students. If just comparing the how bright a light bulb lights up depending on what type of pencil used, then appropriate for all ages.

Background: Pencil lead is made of a mixture of graphite and clay. Graphite can conduct electricity. The more graphite, the better it conducts electricity.

Scenario:
Imagine you are the great superhero Graphene Man, and your arch nemesis (Evil Eraser-man) has trapped you in a small room with a tiny window on the 10th floor of a tall building. On the ground, your sidekick, Buckyboy, is desperately searching for some way to find you. If you could only send him a sign! To make matters worse, your superpowers have been neutralized, so you must use your considerable intelligence to figure this out. All you have are 3 pencils (4H, HB, and 6B), a 9-volt battery, a small light bulb, and 5 alligator clip leads. Unfortunately, the battery and light bulb are both bolted to the floor, and the alligator clip leads just won't stretch. A pencil could help complete the circuit, but which one do you choose? Which one will give the brightest signal? It looks like the light bulb is about to burn out, so you only have 1 shot. Thankfully you always carry your trusty multimeter!

Supplies:

  • 3 pencils: 6B, HB, and 4H – make sure they have sufficiently different amounts of graphite (the difference between HB and 2B is not very dramatic in this activity). The pencils should also be approximately the same length and from the same manufacturer. It works best if they are sharpened at both ends. (Available at any craft store or art supply store)
  • 9-volt battery
  • 9-volt battery snap connector (Radio Shack)
  • E10 Lamp Base with Screw Terminals (Radio Shack)
  • Miniature Incandescent Bulb with an E10 Lamp (Radio Shack)
  • 5 aligator clips (Radio Shack)
  • Project Box (Radio Shack)
  • 6.5 ft. piece of wood (Home Depot)
  • Plastic plumbing hanger strap (Home Depot)
  • Multimeter set to measure resistance (optional)

Adult preparation: Snap the 9-volt battery to the snap connector. Put the battery and connector into a project box with the wire leads sticking out of the holes of the project box. Mount the project box to your piece of wood using plumbing hanger strap so that the battery can't just be removed from the project box. Mount the E10 lamp base, on the other side of the piece of wood such that you can still connect the one battery lead to the lamp base by two aligator clips and one pencil. The other battery lead will be connected to the lamp base by three aligator clips. Screw the bulb into the E10 lamp base, and present the scenario to the participant.

Consider this:

  1. Compare how bright the bulb is when the circuit is completed with the different pencils. Do pencils with more or less graphite make the light bulb glow brighter?
  2. (Optional) Use a multimeter to compare the measured resistance of the different pencils. The higher the measured resistance, the higher electrical resistivity, therefore the lower the electrical conductivity. Do pencils with more or less graphite have a higher measured resistance?

Developed by:
Angela Jones, Ph.D.
Institute for Chemical Education and the Nanoscale Science and Engineering Center
University of Wisconsin – Madison

How does length affect resistance and resistivity?

Scale of Pencil Grades

Age: Appropriate for middle school to high school students

Background: The "lead" in pencils is made of a mixture of graphite and clay. Adding more graphite makes the pencil lead softer and produces a darker stroke. Adding more clay makes the pencil lead harder and produces a lighter stroke. The grading system of pencils goes from H for hardness (more clay) to B for blackness (more graphite). The standard U.S. #2 pencil corresponds closest to the HB pencil. The picture above from Staedtler shows the gradation of their pencils.

What you will do: In this activity, we're drawing lines on a piece of paper and measuring the electrical resistance of that line to learn how the length and thickness of the line affects the measured resistance.

Supplies:

  • Multimeter set to measure resistance (ohms) – available at Radio Shack
  • Pencils with a grading of B (e.g. HB, 2B, 4B, 6B, etc.) - Available at any craft store or art supply store
  • Linked activity sheet [LineOfResistance.pdf]

Instructions: Draw a straight line in the box in the activity sheet. Repeatedly draw on the line until it appears completely dark and try to keep the width of the line as uniform as possible. Use the multimeter to measure the resistance at varying distances along the drawn line. When measuring the resistance, touch the blunt edge (NOT the sharp point) of the multimeter probes to each end of the line. The sharp tip can damage the line.

Consider this:

  1. Does the measured resistance vary with the length of the line?
  2. Does the calculated resistivity vary with the length of the line?
  3. (optional) Draw another line twice as wide – does the measured resistance and calculated resistivity vary with the width of the line?
  4. Repeat the activity with a different pencil. How does the measured resistance and calculated resistivity compare with this pencil? Which has a higher electrical resistivity, one with more clay or one with more graphite?

Discussion:

The measured resistance will vary directly with the distance. The electrical resistivity is an intrinsic property and should therefore be independent of length and cross-sectional area, but in this activity, inconsistencies while drawing the line will result in varied width and thickness of the line thus affecting the results of the calculated resistivity. You can examine the impact by comparing the resistance after adding more and more lines on top of each other (changing the line thickness) or next to each other (changing the line width). The pencil with more clay should have a higher electrical resistivity.

Reference: This activity is a modified version of an activity that is part of the Institute for Chemical Education Kit – Line of Resistance, by Dr. Lawrence D. Woolf.

Developed by:
Angela Jones, Ph.D.
Institute for Chemical Education and the Nanoscale Science and Engineering Center
University of Wisconsin – Madison

Graphene Hopscotch

Hopscotch court

Age: Kids of all ages that enjoy hopscotch

Background: Graphite (the form of carbon in pencil "lead") is made up of layers of carbon that form bonds in a hexagonal pattern. These layers are called graphene. Electricity can flow in graphite (and graphene) along the plane of the graphene layers and not from plane to plane.

What you will do: You play on a hopscotch court that looks like sheets of graphene. As the player hops along the hopscotch court, he or she is acting like electrons flowing through a pencil.

Supplies:

  • Either chalk and sidewalk or a poster printout of the linked hopscotch court. [Poster sized hopscotch court: Hopscotch.pdf][Paper size hopscotch court: Hopscotch_11in.pdf]
  • Beanbag or some other item that can be used to mark position on the court

Instructions:

  1. Either draw the hexagon hopscotch court on the sidewalk with chalk, or print out a poster sized version of the court linked here. Hopscotch.pdf]
  2. Rules of hopscotch
    1. The first player throws a beanbag into hexagon numbered 1, making sure to keep the beanbag entirely in the hexagon.
    2. The first player then jumps over hexagon 1 and lands on hexagon 2 with one foot. The first player then jumps and places both feet on hexagons 3 and 4 at the same time, then jumps with 1 foot on hexagon 5, followed by hexagon 6. The first player then jumps and places both feet on hexagons 7 and 8 at the same time, then jumps with 1 foot on hexagon 9, followed by hexagon 10. Player one then jumps and place both feet on hexagons 11 and 12, then jumps and turn around half a circle, so that the player is facing the other way.
    3. The player returns down the court the same way, they went up it. When the player lands on hexagon 2, he or she picks up the beanbag on hexagon 1, and then jumps into hexagon 1.
    4. The above steps are repeated, but each time, they must first toss the bean bag into the hexagon that is 1 step up. For example, they would toss to hexagon 2, followed by hexagon 3, etc.
    5. If at any time the beanbag does not land in the appropriate hexagon, the player lands on a line or places two feet down for balance, that player's turn is over. If no one wins before it is their turn again, that player continues where he or she left off.
    6. The first player to complete all 12 hexagons wins!
Parents

If you choose to print out the poster version of the hopscotch court, be sure to tape it down securely so that the kids don't slip on it!

Developed by:
Angela Jones, Ph.D.
Institute for Chemical Education and the Nanoscale Science and Engineering Center
University of Wisconsin – Madison

Making Graphene from Pencil Markings

Colors on the silicon wafer compared to graphene thickness

Image from reference 2. Reprinted with permission from AAAS. See Terms and Conditions.

Age: All

Background: In 2004, Andre Geim and Konstantin Novoselov of University of Manchester, UK won a Nobel Prize in Physics for isolating one-carbon atom thick graphene sheets. To separate the graphene sheets from graphite flakes they used Scotch Tape. To tell the difference between one-carbon atom thick graphene sheets and many sheets of graphene, they stuck the tape on a silicon wafer and peeled the tape off. The material that stuck to the wafer could be seen under a optical microscope. A different number of layers of graphene would have have a different color on the wafer. Look at the picture above - the different colors on the wafer are labeled by how thick the layers of graphene are in nanometers (nm).

What you will do: In this activity, you can make graphene using Scotch Tape and a line drawn by a pencil.

Supplies:

  • Scotch tape
  • Pencil
Instructions:
  1. Take a piece of tape, and draw many dark lines on the sticky side of the tape using your pencil.
  2. Take another piece of and stick it on top of the drawn line (sticky side to sticky side of the two pieces of tape)
  3. Gently pull the two pieces apart.
  4. Re-stick the top piece to the bottom and pull apart again. Repeat this 4-5 more times with the same piece of tape. Trying to cover the bottom piece of tape with as much graphite as you can.
  5. Throw away the top piece of tape.
  6. Get a fresh piece of tape, and repeat step 2. As you repeat this step, you'll notice that the bottom piece of tape is gradually covered with a shiny-gray graphite "film."
  7. Repeat step 4, until the "film" is a dull gray. This will likely take 2-3 pieces of tape, depending on how dark your first mark was.
  8. Tada! You likely have graphene on your tape. If you have access to an electron microscopy facility, take your tape them and get them to stick it to a silicon wafer, so that you can see what you made.

Reference:

  1. "The Nobel Prize in Physics 2010". Nobelprize.org. 31 Oct 2011 http://www.nobelprize.org/nobel_prizes/physics/laureates/2010/
  2. Novoselov, K. S.; Geim, A. K.; Morozov, S. V.; Jiang, D.; Zhang, Y.; Dubonos, S. V.; Grigorieva, I. V.; Firsov, A. A., Electric field effect in atomically thin carbon films. Science 2004, 306 (5696), 666-669. [Article]

Terms and Conditions:
Readers may view, browse, and/or download material for temporary copying purposes only, provided these uses are for noncommercial personal purposes. Except as provided by law, this material may not be further reproduced, distributed, transmitted, modified, adapted, performed, displayed, published, or sold in whole or in part, without prior written permission from the publisher.

Developed by:
Angela Jones, Ph.D.1, 2 and Nathaniel Safron2, 3
1Institute for Chemical Education, 2Nanoscale Science and Engineering Center, 3Department of Materials Science and Engineering
University of Wisconsin – Madison

Mechanical Exfoliation to Make Graphene and Visualization

Photo of natural graphite flakes and cleaved silicon wafers

Age: This activity is most appropriate for a high school science class rather than a take home project.

Background: In 2004, Andre Geim and Konstantin Novoselov of University of Manchester, UK won a Nobel Prize in Physics for isolating 1-carbon atom thick graphene sheets. To separate the graphene sheets from graphite flakes they used Scotch Tape. To visualize the graphene, they stuck the tape on a silicon wafer and examined the wafer under an optical microscope. Thin films of graphene are transparent to the naked eye which is why it is believed they will play an important role in the next generation of extremely thin electronics. However, when stuck to the wafer, the added graphene layers interfere with the light causing a shift in colors that allow you to distinguish wafer from graphene, and few-layer graphene from multi-layer graphene. In this activity students use natural graphite to duplicate the mechanical exfoliation technique used to separate graphene sheets from graphite. Ideally this would coincide with a trip to an electron microscope facility. The instructor's preparation and background description as well as a student's worksheet are included in linked activity sheet. [MechanicalExfoliation.pdf]

Developed by:
Angela Jones, Ph.D.1, 2 and Nathaniel Safron2, 3
1Institute for Chemical Education, 2Nanoscale Science and Engineering Center, 3Department of Materials Science and Engineering
University of Wisconsin – Madison

Smell Obliterator

Photo of smell obliterators

Age: All

What you will do: Both baking soda and activated carbon are used to get rid of bad odors. In this activity, you are going see if baking soda or activated carbon is better for a variety of smelly substances.

Supplies:

  • Three 32 ounce yogurt containers with lids (or any other similarly sized container with a lid)
  • Baking soda
  • Activated carbon (from an aquarium or pet store)
  • 3 ounce bathroom cups
  • Banana, vinegar, pickle juice, apple, perfume, any other smelly substance you can think of

Instructions:

  1. Add 1/3 a cup of baking soda to one of the yogurt containers
  2. Put 1/3 a cup of activated carbon to another yogurt container
  3. The third yogurt container is your control, so that you can compare the ability of baking soda and activated carbon at neutralizing or absorbing the smell.
  4. Add an equal amount of whatever smelly substance you are testing into bathroom cups and place the cups into the container.
  5. Close the containers and wait 30 minutes.
  6. After 30 minutes, compare the three containers to see whether the baking soda or activated carbon did a better job.
  7. After a few attempts you might need to use fresh baking soda or activated carbon.

Consider this:

  1. What odors are better removed using baking soda?
  2. What odors are better removed using activated carbon?

Discussion:

Baking soda is the common name for the chemical sodium bicarbonate; it reacts to neutralize odors. Baking soda is amphoteric meaning it reacts with acids and bases. The thought is, in adding baking soda to your refrigerator, odors caused by acids (example, sour milk) and bases (example, smelly fish) will be neutralized when the vapors come into contact with the baking soda. The problem is baking soda is also hygroscopic which means it can absorb water from the environment and gets hard and clumpy, reducing its surface area making harder for vapors to come into contact with the baking soda. Activated carbon or activated charcoal, on the other hand, is essentially charcoal with many, many tiny pores which means it has A LOT of surface area. Odor causing gases can go through the pores, and the carbon will adsorb odor causing chemicals. Some odors are more effectively neutralized with baking soda and others are more effectively adsorbed by activated carbon.

SAFETY!

Safety: If you add vinegar to the baking soda container, be careful not to spill the vinegar. The vinegar contains acetic acid that will react with the baking soda producing carbon dioxide. If you close the container, the carbon dioxide will fill the container resulting in increased pressure that could cause the lid to pop off and unwanted spraying when opened.

Developed by:
Angela Jones, Ph.D.
Institute for Chemical Education and the Nanoscale Science and Engineering Center
University of Wisconsin – Madison

Terrariums

Photo of the bottle terrariums

Age: All

Background: Life on Earth depends on the ability of water, carbon, and nitrogen to cycle. A terrarium is a miniature version of that. It is sealed off with enough water and nutrients so a plant can grow without much work on your part. There are several things that can go into a terrarium: potting soil, aquarium rocks, activated carbon, sheet moss and water. Some of these are more important than others.

What you will do: In this activity, you're going to make five terrariums in order to see which of these is most important in creating our miniature ecosystem!

Supplies:

  • 5 one-liter bottles (Desani has a nice height)
  • Craft knife (any craft store or art supply store)
  • Low-temperature hot glue gun and appropriate glue (hot-temperature gun glue will melt the plastic when applied to the water bottle)
  • Activated carbon (from an aquarium or pet store)
  • Aquarium rocks (from an aquarium or pet store)
  • Potting mix (garden store or home store)
  • Dried sheet moss (garden store or home store)
  • Funnel with a spout smaller than the water bottle mouth but larger than aquarium rocks
  • Labels for each terrarium
  • Suggested plants – Baby tears, rhizomatous begonias, ornamental grass, pepromias (Note: you'll want enough of the same plant to go in each of the terrariums. Baby tears are nice because you can buy one plant and easily split it up to put in each terrarium.)

Instructions:
  1. Adults, use a craft knife to cut around the circumference (outer edge) of the water bottle about 3 inches from the bottom of the bottle. Put the tops aside, to re-attach later.
  2. Split the plant so that you have the same size plant in each terrarium.
  3. You will make 5 terrariums:
    1. control (a complete terrarium) – see ingredients for a complete terrarium below
    2. same as the complete terrarium but without aquarium rocks
    3. same as the complete terrarium but without activated carbon
    4. same as the complete terrarium but without lower moss
    5. same as the complete terrarium but without upper moss
  4. Once you've added all of the ingredients to the terrarium, take the top of the bottle and cover the plant.
  5. Take your low-temperature glue gun and seal the bottle shut as well as possible so that there are no gaps in the bottle. (Reminder: using hot-temperature glue gun will melt the water bottle)
  6. Label each terrarium.
  7. Water just a little (~ 2 tablespoons of water).
  8. Place the bottle in a windowsill and watch it grow.
  9. Within a couple of days you should see water condensing on the top of the bottle.
  10. You'll only need to add more water if you don't see any water drops on the top of the bottle.
  11. Watch your 5 terrariums for the first month. Take pictures so that you can compare the plants from the start to the end of the month.

Complete Terrarium:
  1. Put one half-inch layer of aquarium rocks in the bottom of your bottle base.
  2. Layer one half-inch of activated carbon on top of the rocks.
  3. Pull apart the sheet moss (lower moss) to add a layer on top of the activated carbon.
  4. Layer about 1.5 inches of potting mix on top of the sheet moss.
  5. Plant your plant such that the top of the plant is level with the top of the potting mix.
  6. Add a layer of sheet moss (upper moss) on top of the potting mix and around the plant.

Consider this:

The complete terrarium is called the "control" because it is the terrarium that you are comparing all the others against. The other four terrariums are each adjusting a "variable" something you are changing compared to the control.

  1. Did any of the plants grow taller or spread out faster than the others?
  2. If you open the terrarium up, do some of them smell worse than others?
  3. Can you think of other variables you might want to test with your terrariums? Do an experiment to test another variable.
  4. Do you think we should have duplicates for each of our variables?

Discussion:

Plants in all of the terrariums will likely grow. There might be differences in how quickly the plant grows initially, but after a few months the plants eventually might all look about the same. In the terrarium, the aquarium rocks help provide drainage for the water. The activated carbon helps to filter the water, preventing odors and microbes from killing your plants. The lower moss helps to separate the potting soil from the activated carbon and helps with drainage, and the upper moss helps hold in moisture.

Examples of other variables you might test could be how much light they receive, how often you water, and whether a different plant might work better? There are many other variables you could test!


SAFETY!

Safety: Adults should cut the water bottles and use the glue gun.


Reference: Martin, T.; Clineff, K.,The New Terrarium. Clarkson Potter/Publishers: New York, 2009.


Developed by:
Angela Jones, Ph.D.
Institute for Chemical Education and the Nanoscale Science and Engineering Center
University of Wisconsin – Madison

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