Materials Included In Kit

Additional Materials Required

Prelab Preparation

Activity A
Cut apart each set of object cards, mix each set separately, and place each set of 15 cards in a resealable plastic bag.

Activity B

1. Place a penny in the bottom of each of four small disposable Petri dishes.
2. Place two neodymium magnets in separate resealable plastic bags under two Petri dishes.
3. Using a disposable pipet, carefully add enough ferrofluid to each of the two dishes so the ferrofluid forms a dome with spikes over the magnet. Note: Do not add too much ferrofluid or the dome of fluid will mound up too high and not show any spikes.
4. Keeping the magnets in place under the Petri dishes, place the covers on the dishes and seal around the circumference of each dish with masking tape. Press the tape firmly against the sides of the cover and bottom of the dishes for a good seal. Label the side of each dish with the letter B.
5. Carefully remove the magnets from underneath the dishes. Note: Once the ferrofluid has been added to the dishes it is important to keep the dishes level. Ferrofluid will coat the inside surface, and if it comes in contact with the cover of the dish, observations will be difficult, if not impossible. If this happens, let the covered dish stand with a magnet centered underneath until the ferrofluid flows back to the bottom of the dish. This may take up to 10 minutes before the dish is transparent enough to see through and from 30 minutes up to an hour until more detailed observations may be made.
6. In the other two Petri dishes, measure and add 3 g of iron filings to each and enough tap water to match the level of ferrofluid in the dishes labeled B. Note: Iron filings will not rust as quickly in tap water compared to deionized water.
7. Place the covers on the Petri dishes and use masking tape around the sides to seal. Label the side of the dishes with the letter A.

Activity C
For best results, make the 2% sodium alginate solution the day before the lab and add the iodine and starch for the sodium alginate test solutions the day of the lab.

Sodium Alginate Solution, 2%: Measure 4 g of sodium alginate into a 400-mL beaker. Add 200 mL of distilled or deionized water and a stir bar. Stir on a magnetic stirrer for 1–2 hours or until the solid dissolves. For best results, allow the mixture to sit overnight to give a uniform solution. If a magnetic stirrer is not available, simply stir thoroughly and allow the mixture to sit overnight.

Iodine/Sodium Alginate Solution: Measure 50 mL of 2% sodium alginate solution into a 100-mL beaker. Add 1 mL of the tincture of iodine solution and stir.

Starch/Sodium Alginate Solution: Measure 50 mL of 2% sodium alginate solution into a 100-mL beaker. Add 1 mL of the 0.5% starch solution and stir.

Activity D

1. Pour about 50 g of white sand into one large weighing dish. Label the dish, “Sand.”
2. Pour 50 g of the Mystic Sand into a second large weighing dish. Label the dish, “Mystic Sand.”
3. Place two plastic spoons in each dish. Note: Both student groups may share the containers of sand and Mystic Sand.

Safety Precautions

Iodine solutions are irritating to eyes, irritating and mildly corrosive to skin and toxic by ingestion. Ferrofluid is a skin and eye irritant and will stain skin and fabric. Although Mystic Sand and white sand are considered non-hazardous, they may be irritating to body tissues and eyes. Do not ingest or get into the eyes. Wear chemical splash goggles, chemical-resistant gloves and a chemical-resistant apron. Remind students to wash their hands thoroughly with soap and water before leaving the laboratory. Please review current Safety Data Sheets for additional safety, handling and disposal information.

Disposal

Please consult your current Flinn Scientific Catalog/Reference Manual for general guidelines and specific procedures, and review all federal, state and local regulations that may apply, before proceeding. Ferrofluid used in the activity as written may be returned to the bottle and stored for future use. Materials coated in ferrofluid may be wiped clean with paper towels and the paper towels thrown away in the regular trash according to Flinn Suggested Disposal Method #26a. Excess tincture of iodine solution may be may be reduced with sodium thiosulfate according to Flinn Suggested Disposal Method #12a. Polymer gel products obtained in this lab may be disposed of in the trash according to Flinn Suggested Disposal Method #26a. Excess calcium chloride and starch solutions may be disposed of down the drain with plenty of excess water according to Flinn Suggested Disposal Method #26b. Mystic Sand and white sand may be used over and over again. Pour off as much water as possible and pour the sand onto some paper towels or newspapers. When dry, return the Mystic Sand and white sand to their respective containers. If disposal of Mystic Sand is desired, you may dispose of it, as well as the white beach sand, in the solid trash according to Flinn Suggested Disposal Method #26a.

Lab Hints

• For best results, set up two stations for each lab activity. This will allow eight groups of students to rotate through four activity stations in a 45- to 50-minute lab period. A double lab period (two class periods) will allow time for both an introduction to nanotechnology before the lab and for a collaborative class discussion after lab.
• Each activity is a self-contained unit and may be completed in any order. Students should need only 8–10 minutes per station—keep the pace fairly brisk to avoid dawdling. Post-Lab Questions may be answered during any down time between stations.
• Prelab preparation is an essential component of lab safety, and it is also critical for success in the lab. Standing in front of the lab station is not a good time for students to be reading the activity for the first time. Having students complete the written prelab assignment for this lab will help ensure that students are prepared and can work safely and efficiently in the lab.
• For Activity C, set up a large waste beaker for students to empty the contents of the spot plates into. The spot plates may then be rinsed with water and wiped dry with paper towels.
• For Activity D, set up two filter systems with support stands, ring clamps, funnels and filter paper. Students may use the plastic spoon to scrape the wet sand and the Mystic Sand from the weighing dishes into the respective filters. The weighing dishes may then be wiped dry with paper towels for the next group. Once all groups have completed the lab, remove the filter papers from the funnels and lay them flat on paper towels or newspapers and allow the sand and Mystic Sand to air dry for reuse.
• Although the iron filings are made from a nonrusting alloy, storing them in water will eventually cause corrosion. Pour off excess water and then pour the iron filings onto paper towels or newspapers, blot dry and allow to air dry completely for reuse.
• Ferrofluid can be messy. Please read the following handling tips.
  • Always wear chemical splash goggles, chemical-resistant gloves and a chemical-resistant apron when working with ferrofluid, both in preparation and cleanup.
  • Covering the work surface with newspaper or paper towels during preparation and cleanup is recommended.
  • When dispensing ferrofluid, gently squeeze the pipet bulb and aim carefully so the ferrofluid does not splatter.
  • Keep any magnets inside a plastic bag to protect them from coming in contact with the ferrofluid.
  • Remove objects from ferrofluid with nonmagnetic forceps and either throw away or wipe clean with paper towels.

Teacher Tips

• This versatile nanotechnology activity-stations lab can be part of many areas in the science curriculum, with applications in measurement and the metric system, physical and chemical properties, magnetism, science and technology, engineering, health and biomedical and consumer science.
• Allow students to research applications of nanotechnology and report their findings to the class.
• Commercial Ferrofluid is available from Flinn Scientific (Catalog No. AP7432) and comes with additional suggested demonstrations of the unique properties of this product.

Answers to Prelab Questions

1. The average growth rate of fingernails is 0.1 mm per day. How many nanometers is this per day?

   0.1 mm/day x 1,000,000 nm/1 mm = 100,000 nm/day

2. Using the answer to Question 1, how far in nanometers would a fingernail grow in one second?

   100,000 nm/day x 1 day/24 hr x 1 hr/60 min x 1 min/60 sec = 1 nm/sec

3. What safety and procedural precautions need to be taken when working with ferrofluid?

   Ferrofluid is a skin and eye irritant and will stain skin and fabric. Wear chemical splash goggles, chemical-resistant gloves and a chemical-resistant apron. Do not open the Petri dishes. Wash hands thoroughly with soap and water before leaving the laboratory. The dish containing ferrofluid must be kept upright and level. Do not remove the magnet from the plastic bag. Be very careful that the magnet stays under the Petri dish and away from the outer edge of the dish. Bringing the magnet too close to the side of the dish may cause the ferrofluid to leak out.

4. In Activity C, why is it important to rinse the forceps with distilled water after each use?

   The forceps should be rinsed after each use to prevent contamination from one well to another.

Sample Data

B. Properties of Ferrofluid

C. Encapsulation in Medicine D. Water-Repellant Sand

Answers to Questions

A. How Big? How Small?

1. Number the objects below from 1 to 15, with 1 being the largest and 15 the smallest:
   {12081_Answers_Table_4}
2. Which objects were more difficult to arrange correctly? Why do you think this is so?

   The smallest items were more difficult to arrange correctly. These are not as familiar as larger objects; they cannot be seen to make comparisons with other objects, etc.

3. Would a carbon nanotube that is 4 nm long and 2 nm wide be visible under a light microscope? Why or why not?

   No, a carbon nanotube is smaller than the wavelength of visible light; therefore it cannot be seen with a light microscope.

B. Properties of Ferrofluid

1. Describe the difference in the movement of the penny with respect to the ferrofluid with and without the presence of a magnetic field (steps 2 and 6 of Activity B Procedure). Explain your observations.

   The penny stayed on the bottom of the dish and the ferrofluid flowed over the penny without the presence of a magnetic field. When the magnet was brought to the bottom of the dish the ferrofluid formed a spiked dome over the magnet. The penny was lifted up over the dome of ferrofluid. The magnetic particles of the ferrofluid became more concentrated in the presence of a magnetic field, resulting in an area in the fluid of greater density than the penny.

2. Use information from the Background section along with your observations to explain why ferrofluid is considered a “nano” product.

   Ferrofluid consists of extremely small, solid-phase magnetic particles that are only about 10 nm in diameter suspended in a liquid. At the nanoscale, gravitational forces are negligible and intermolecular bonding forces become more important. Rather than settle out of solution as a solid, the so-called nanoparticles remain suspended in the liquid, forming a stable colloid. The nanoparticles of magnetic material behave differently in a magnetic field than the large-scale iron filings.

3. NASA first explored the use of ferrofluid to control liquid rocket fuels in zero gravity. What other possible applications of ferrofluid can you think of?

   Accept all reasonable answers. Today ferrofluid is used in audio speakers, in separating materials during mining and recycling processes, in manufacturing semiconductors, in rotary seals and in the biomedical field.

 C. Encapsulation in Medicine

1. Explain the difference in color between the spheres that formed in well A1 and the spheres formed in well B1.

   The spheres in well A1 were yellow because they contained iodine. The spheres in well B1 were colorless because they contained starch.

2. Explain any changes observed in and around the spheres in wells A2 and A3.

   When the iodine-encapsulated spheres were placed in the starch solution in well A2, the solution became dark blue around the outside of the capsules, indicating the diffusion of iodine out of the capsules. The sphere color remained yellow, indicating the starch solution did not diffuse into the spheres. No change was observed in well A3 since it did not contain starch.

3. Explain any changes observed in and around the spheres in wells B2 and B3.

   No change was observed in well B2 with the starch solution. When the starch-encapsulated spheres were placed in the iodine solution in well B3, the spheres became dark blue inside, indicating the diffusion of iodine into the capsule. No change was observed around the spheres, indicating the starch did not diffuse out of the spheres.

4. This activity is a macroscale model of what could take place at the nanoscale in medicine. What questions would need to be considered in using encapsulation to deliver chemotherapeutic drugs to only cancer cells?

   Accept all reasonable answers. Some questions may include: What molecules could be attached to the spheres that would only target cancer cells? How will the drug be released once the capsule is inside the cell? How will the encapsulated drug be introduced into the body?

D. Water-Repellant Sand

1. Describe how the two types of sand exhibit either hydrophobic or hydrophilic properties.

   Since the white sand soaks up or attracts water, it is hydrophilic or “water-loving.” The Mystic Sand is not wetted with water but repels it; therefore, it is hydrophobic or “water-fearing.”

2. Roots of most plants need water and air. If plants are over-watered, air pockets in the soil become filled with water and the tiny root hairs cannot get needed oxygen. How would adding Mystic Sand to potting soil help with the problem of overwatering?

   By adding the treated sand to potting soil, the hydrophobic nanoparticles would allow air to flow between them but not water, creating open-air channels from the surface of the soil to the root hairs. Water would still reach the roots because the rest of the potting soil would have hydrophilic particles.

3. The textile industry has used nanotechnology to develop fabric that repels liquid. If you were to design an experiment to test the effectiveness of liquid-repellant fabric, what question might be asked that would begin the process of investigation?

   Accept all reasonable answers. Some possible questions include: Does the fabric repel oil-based liquids as well as water-based liquids? Does detergent or fabric softener affect the liquid-repelling ability of the fabric?

References

Hemling, M. A.; Sammel, L. M.; Zenner, G.; Payne, A. C.; Crone, W. C. Nanomedicine: Problem solving to treat cancer. Science Scope, Nov. 2006, pp 32–37.

Robson, D. P. Magic Sand. ChemMatters, April 1994, pp 8–9.

Size Matters: Introduction to Nanoscience, NanoSense. http//www.nanosense.org (accessed July 2018).

Introduction

From nanofabric to nanobots, nanotechnology has created so much “buzz” that it’s hard to tell where the science ends and the science fiction begins. Wherever it may lead in the future, nanotechnology begins with the preparation, characterization, and use of particles and structures that are between 1 and 100 nanometers in at least one dimension. Nanoparticles have unique physical and chemical properties that are significantly different than the properties of the same materials at the macroscopic level. Explore some of the fascinating developments in the rapidly growing field of nanotechnology in this activity-stations lab.

Concepts

• Nanotechnology
• Disease control
• Hydrophilic versus hydrophobic
• Physical and chemical properties
• Relative size
• Diffusion

Background

A nanometer (nm) is a measurement of length that is one billionth of a meter (10^–9 m). Imagine making two marks that are a millimeter (10^–3 m) apart on a piece of paper and then fitting a million more marks in between! The width of human hair ranges from 17,000 to 180,000 nanometers.

Properties and behaviors of materials can be quite different at the nanoscale. An example of this difference is seen in the properties of carbon. Graphite is a familiar macroscale form of carbon. It is a conductor because each carbon atom is connected to three other carbon atoms in a layer via strong covalent bonds. The fourth valence electron on each carbon atom is shared by all the carbon atoms in one layer. These electrons move freely within the layer, making graphite an excellent conductor (see Figure 1). The layers also make graphite very soft and brittle. On the nanoscale we find carbon nanotubes, structures of carbon molecules that can be centimeters in length but only a few nanometers wide.

The carbon atoms are bonded together in a similar manner as those in graphite, forming hexagonal structures that are connected in a cylindrical shape instead of layers. The nanotubes look something like a roll of chicken wire (see Figure 2). Carbon nanotubes are efficient electrical and thermal conductors and their shape makes them very strong with a tensile strength over 100 times greater than steel. Nanotechnology is currently being applied in a vast number of fields including forensics, agriculture, environmental, medical, textiles, electronics, transportation, aerospace and even sports! Examples that will be investigated in this lab are described.

Ferrofluid
Ferrofluid was developed in cooperation with NASA in the 1960s. Ferrofluid consists of extremely small, solid-phase magnetic particles about 10 nm in diameter that are coated with a surfactant and suspended in a liquid. All objects have mass and are affected by the force of gravity. However, at the nanoscale, gravitational forces are negligible and chemical and intermolecular bonding forces become more important. Rather than settle out of solution as a solid, the magnetic nanoparticles remain suspended in the liquid, forming a stable colloid, and the surfactant coating prevents the particles from clumping together. Their small size and slippery coating give the solid magnetic particles liquid-like properties—a magnetic liquid!

Encapsulation
One drawback of many cancer-fighting drugs is their side effects. The drug not only acts on the cancer cells, but often adversely affects healthy cells, too. Now scientists are developing ways to use nanoparticles as drug-carriers that are designed to deliver the drug to only the targeted cells by a method called encapsulation. Tiny (100–150 nm) molecular “cages” are filled with a chemotherapeutic agent (cancer-killing compound) and are sheathed with molecules that trick the cancer cells into allowing entry of the nano-sized capsules. Once inside, the medicine is released, effectively killing the cancer cell without harming any healthy cells.

Water-Repellant Sand
Ordinary beach sand consists mostly of mineral quartz broken down into tiny pieces. The chemical name for sand is silicon dioxide (SiO₂). In sand, silicon and oxygen atoms are covalently bonded in a three-dimensional network made of billions of atoms. The silica network contains two oxygen atoms for every silicon atom with the surface of the sand containing mostly the oxygen atoms. These oxygen atoms form polar covalent bonds with hydrogen atoms (see Figure 3), and thus are able to form hydrogen bonds with water. For this reason, water is attracted to the sand, and sand grains are said to by hydrophilic or “water-loving.” Mystic Sand is white beach sand that has been treated with a colored dye and coated with finely divided nanoparticles of chemically treated silica. The coating contains large bulky hydrocarbon groups that attach to the sand and give it a new surface of nonpolar covalent bonds (see Figure 4). The nonpolar surface does not attract water and the particles of the treated sand are said to be hydrophobic or “water-fearing.” In addition to this hydrophobic effect, the surface tension of the water molecules prevents them from flowing in between the nanoparticles on the surface of the sand in a similar way that the surface tension of a water droplet keeps it on top of the hairs on a caterpillar’s back. Air can still flow between the nanoparticles on the surface of the sand.

Experiment Overview

The purpose of this activity-stations lab is to investigate the world of nanotechnology. Four mini-lab stations are set up around the classroom. Each activity focuses on a particular concept associated with nanoscience: relative size, unique properties and behavior of nanoparticles and models of applications of nanotechnology. The activities may be completed in any order.

1. How Big? How Small?
2. Properties of Ferrofluid
3. Encapsulation in Medicine
4. Water-Repellant Sand

Materials

Prelab Questions

Read the Background, Safety Precautions and Procedure for each activity, and then answer the following questions on a separate sheet of paper.

1. The average growth rate of fingernails is 0.1 mm per day. How many nanometers is this per day?
2. Using the answer to Question 1, how far in nanometers would a fingernail grow in one second?
3. What safety and procedural precautions need to be taken when working with ferrofluid?
4. In Activity C, why is it important to rinse the forceps with distilled water after each use?

Safety Precautions

Wash hands thoroughly with soap and water before leaving the laboratory. Ferrofluid is a skin and eye irritant and will stain skin and fabric. Wear chemical splash goggles, chemical-resistant gloves and a chemical-resistant apron. Do not open the Petri dishes. Iodine solutions are irritating to eyes, irritating and mildly corrosive to skin and toxic by ingestion. Although Mystic Sand and white sand are considered non-hazardous, they may be irritating to body tissues and eyes. Do not ingest or get into the eyes. Please follow all laboratory safety guidelines.

Procedure

Activity A. How Big? How Small?

1. Obtain a set of object cards and place all 15 cards with the picture of the object facing up (letter side down) on the work surface. 
2. Arrange the cards in order of relative size, starting with the largest object at the left end of the row and ending with the smallest object at the right. 
3. Once all the cards are arranged in order of size, turn each card over. If arranged correctly, the cards will spell a word that refers to the preparation, characteristics and uses of nano-sized particles. Note: Since some letters are found more than once in the answer, as an extra check small letters printed on the bottom right corner of each card spell the name of the company that published these instructions. 
4. If some of the object cards were not in the correct order, arrange them correctly. 
5. Number each object listed in Part A on the Nanotechnology worksheet from 1 to 15, with 1 being the largest object and 15 the smallest. 
6. Mix up the cards and return them to the plastic bag.

Activity B. Properties of Ferrofluid
Note: Petri dishes containing ferrofluid must be kept upright and level. Ferrofluid will coat the inside surface, and if the ferrofluid comes in contact with the cover of the dish, observations will be difficult, if not impossible. 

1. Inspect the two prepared Petri dishes labeled A and B without picking them up and record observations about the contents of each dish in the table for Part B on the Nanotechnology worksheet. 
2. Keeping the dishes flat on the work surface, gently shake each dish from side to side and observe how the contents move. Record observations in the data table. 
3. One partner should carefully pick up dish A. Remember: Keep the dish level.
4. While one partner is holding the dish securely, another partner should obtain the neodymium magnet inside a sealed plastic bag and slowly and carefully bring the magnet up from below the dish to the bottom of the dish, away from the penny (see Figure 5). Note: DO NOT REMOVE the magnet from the plastic bag. Record any changes observed in the contents of the dish.
   {12081_Procedure_Figure_5}
5. Move the magnet around so it moves under the penny. Record observations in the table.
6. Set dish A down and repeat steps 3–5 with dish B. Note: BE VERY CAREFUL that the magnet stays under the Petri dish and away from the outer edge of the dish. Bringing the magnet too close to the side of the dish may cause the ferrofluid to leak out. 
7. Carefully remove the magnet from the bottom of dish B and set both items down on the work surface away from each other.

Activity C. Encapsulation in Medicine

1. Fill one extra-large-bulb disposable pipet with the iodine/sodium alginate solution and a second extra-large-bulb pipet with the starch/sodium alginate solution. 
2. Fill one thin-stem pipet with tincture of iodine solution, and a second thin-stem pipet with 0.5% starch solution. 
3. Place the reaction plate on top of a 3" x 5" index card. 
4. Pour the 0.3 M calcium chloride solution into wells A1 and B1 until each well is about ¾ full (see Figure 6).
   {12081_Procedure_Figure_6}
5. Add distilled water to each of the remaining four wells. Note the letters and numbers for each well (A2, A3, B2, B3). Fill to about ¾ full. 
6. Add 8 drops of the starch solution to the middle wells A2 and B2. Stir with a toothpick to mix. 
7. Add 10 drops of the iodine solution to the far-right wells A3 and B3. Stir with a clean toothpick to mix. 
8. Hold the pipet filled with the iodine/sodium alginate solution a few centimeters above the surface of the CaCl₂ solution in well A1. Release 12 drops into the CaCl₂ solution. Observe the color and appearance of the spheres produced in well A1. Record all observation in the table for Part C on the Nanotechnology Worksheet. 
9. Using forceps, carefully pick up a sphere from the CaCl₂ solution and place it in the middle well (A2) filled with dilute starch solution. Add five more spheres to this well in the same manner. Observe and record any changes that occur with the spheres.
10. Rinse the forceps with distilled water and repeat step 9, adding spheres from well A1 to the far-right well (A3) containing dilute iodine solution. Observe and record any changes that occur with the spheres.
11. Rinse the forceps and repeat steps 8–10, this time using the starch/sodium alginate solution and the three wells in row B (B1, B2 and B3).
12. Consult your instructor for appropriate disposal procedures. Wipe the reaction plate dry with paper towels.

Activity D. Water-Repellant Sand

1. Obtain two medium weighing dishes. 
2. Using a spoon, add a half-spoonful of white sand to one dish. 
3. Using a clean spoon, repeat step 2, adding a half-spoonful of Mystic Sand to the second dish. 
4. Gently shake each dish back and forth, keeping the dishes in contact with the work surface. Observe the motion of each type of sand and record observations in the table for Part D on the Nanotechnology Worksheet. 
5. Using the spoon for the white sand, push the white sand into a doughnut shape—a circle with a well in the center. 
6. Using the Mystic Sand spoon, repeat step 5 with the Mystic Sand. 
7. Fill a disposable pipet with water. 
8. Gently add several drops of water into the well in the center of the white sand. Record your observations. 
9. Continue to add water to the white sand until the bottom of the dish is just covered with water.
10. Repeat steps 8–9 with the Mystic Sand. Record your observations.
11. Repeat step 4.
12. Using the spoon, scoop up some of the white sand and water and pour it back into its weighing dish. Record your observations. Wipe the spoon dry and return it to the container of white sand.
13. Repeat step 12 with the Mystic Sand. Record your observations. Wipe the spoon dry and return it to the container of Mystic Sand.
14. Consult your instructor for appropriate cleanup and disposal procedures.

Student Worksheet PDF

12081_Student1.pdf