Materials Included In Kit

Additional Materials Required

Prelab Preparation

Construction of Additional Overflow Cans

A classroom set of overflow cans is needed for this lab, although one overflow can could reasonably be shared by all groups if they determine volume in shifts. Overflow cans may be purchased from Flinn Scientific (Catalog No. AP4627) or an overflow setup can be made by setting a beaker in a Petri dish. Fill the beaker with water until it will just spill over. Add the Grow-Dino carefully and pipet the overflow water from the Petri dish into a graduated cylinder to determine its volume. Alternately, overflow cans can be constructed fairly simply on your own. Below are a few options for constructing your own class set. Select containers based on the size of the objects to be measured. Full-grown Grow-Dinos will fit in a cut-off 2-L plastic bottle. The following materials will be needed:

Materials—Option 1                      
Drinking straw or jumbo pipet
Hole punch
Soda bottle, 2-L

Materials—Option 2
Coffee can or large soup can
Drinking straw or jumbo pipet
Power drill

Procedure

1. If you are using a plastic 2-L bottle, cut the base to the desired height. If using the can, use as is.
2. Punch a hole in the plastic bottle or drill a hole in the can approximately one inch down from the rim.
3. Cut a 2-inch piece of drinking straw or pipet stem and pull it snugly into the hole.
4. To use, fill until the water is exactly level with the overflow spout. Then place the Grow-Dino (or other object of unknown volume) in the can and catch the overflow water in a graduated cylinder. The volume of the displaced water is equal to the volume of the object.

Safety Precautions

While the materials in this lab are not considered hazardous, always follow appropriate laboratory safety rules.

Disposal

Allow the Grow-Dino to dry out and it will return to its original size. For best lab results, use a fresh Grow-Dino each time the experiment is performed.

Teacher Tips

• Enough materials are provided in this kit for 30 students working in pairs or for 15 teams of students. This lab works well with teams of two to four students.
• It is a good idea to start this lab on a Monday. The entire lab activity takes five days to gather the data and then additional in-class or out-of-class time for data analysis and graphing. The greatest changes will occur between days one and three. If the lab is started on a Friday, the dinosaur will not be measured again until the following Monday.
• Warn students to use cold rather than hot water. Hot water will partially dissolve the Grow-Dinos.
• Once placed in water, the Grow-Dinos will achieve their maximum size in about four days, depending on the hardness of the tap water. If your tap water is very hard and high in minerals, the Grow-Dinos may take longer to grow and will not grow as large. Distilled, deionized, or bottled water may be used, although this is not required.
• The Grow-Dinos can be stored in large zipper-lock bags with the students’ names or group names written on the outside with a permanent marker.
• Use fresh tap water each day and be sure the Grow-Dino is covered with water.

Further Extensions

• The growth of the Grow-Dinos can be altered by placing them in solutions of different osmotic potentials (e.g., salt water, sugar water, syrup, oil).
• Allow students to continue measurements on the Grow-Dino for additional days. Will it continue to grow? What is its maximum size?

Sample Data

Note: Data may vary greatly.

Answers to Questions

1. How many times larger in area do Grow-Dinos get from start to finish? (See Graph 1.)
   About 15 times larger.
2. Do all four of the measurements on Graph 2 increase at the same rate? Explain. On what days is the rate of growth the greatest? The least? Why does the rate of growth change?
   No, the perimeter increases at the greatest rate and the thickness increases at the slowest rate. Greatest growth is seen on Day 1; least growth is seen on Day 4. The rate of growth slows down because as the Grow-Dino becomes more saturated, the rate of water absorption slows down.
3. How much of the mass of the Grow-Dino is water on each day? (See Graph 3.)
   Day 1 = 0 g; Day 2 = 14 g; Day 3 = 35 g; Day 4 = 51.6 g; Day 5 = 64 g. These values were calculated by subtracting the original mass of the Grow-Dino (1.5 g) from the mass on each day.
4. How many times its own weight can the Grow-Dino material absorb? (See Graph 3.)
   65.5 g/1.5 g = 43.7 times its own weight.
5. In what other ways might the Grow-Dino material be useful?
   This material absorbs fluids well and might be useful in diapers, spill control materials, and hazardous waste drums.
6. Explain what the information on Graph 5 provides and why it is useful.
   For example, a graph of density vs. time shows that as the Grow-Dino absorbs water, its density becomes closer to that of water.
7. The claim made on the box that holds the dinosaur packages says “Grows over 600% larger in water!” Is this claim true—did the Grow-Dino grow 600%? If so, what measurements increased by 600%? What measurements did not increase by 600%?
   To determine percent growth in mass, for example, use the following equation:
   {11944_Answers_Equation_1}
   Therefore yes, the Grow-Dino did grow over 600% in water (in terms of mass). Students results for percent growth for each factor may vary greatly. Sample calculations for percent growth using the Sample Data is as follows:
   {11944_Answers_Table_1}

References

Special thanks to John Mauch and Ira Hickman for developing this activity. John and Ira taught together at Pasco High School in Pasco, WA.

Hickman, Ira. Physical Science Projects—For Integration and Cooperative Learning; Kendall/Hunt: Dubuque, IA, 1997; pp 1–11.

Introduction

Do growing dinosaurs really grow over 600% when placed in water, as the package claims? Let’s investigate the growth of a polymer Grow-Dino!

Concepts

• Measurement
• Polymers

Background

A Grow-Dino is a small animal figurine made from sodium polyacrylate, a super-absorbent polymer found in disposable diapers. The Grow-Dino polymer dinosaur will be placed in water for several days and, during this time, the growth of the Grow-Dino will be traced daily on graph paper. The physical measurements of length, height, thickness, perimeter, area, volume, mass and density will be investigated. The changes that occur in the Grow-Dino as it is soaked in water will then be graphed. The ability to make and use various forms of measurement is essential to making accurate observations of the world around us. This lab activity will provide practice in measuring, graphing and making calculations.

Materials

Safety Precautions

While the materials in this lab are not considered hazardous, always follow appropriate laboratory safety rules.

Procedure

Day 1

1. Trace the Grow-Dino on the graph paper provided. (Note: Put the Grow-Dino in one corner of the paper rather than right in the middle so the same graph paper can be used for all five days.) Label this outline as Day 1, or make a color-coded key (using different-colored inks) for each of five days.
2. Measure the length of the Grow-Dino traced on the graph paper (to the nearest millimeter). Record the length in the Dino Data Table. (Note: Accuracy in measurement is very important.)
3. Measure and record the height (from head to foot) of the Grow-Dino.
4. Measure and record the thickness (width) of the Grow-Dino.
5. The distance around the outside of an object is known as its perimeter. To measure the perimeter of the Grow-Dino, take a piece of string and place it on the outline of the Grow-Dino traced on the graph paper. What length of string (in cm) did it take to outline the Grow-Dino? Record the total string length in the perimeter row of the Dino Data Table.
6. Area is the amount of space an object takes up on a flat surface (in two dimensions). Measure the area of the Grow-Dino by counting the squares that the Grow-Dino covers on the graph paper. Estimate the area of any partially covered squares and add this to the total area. Note: Due to measurement limitations, area rather than surface area is measured.
7. The amount of matter in an object is known as its mass. Objects that have a lot of matter are heavier than objects with less matter. Determine the mass of the Grow-Dino by weighing it on a balance. (Note: Be sure the Grow-Dino is dry before massing it.) Record the mass of the Grow-Dino in the Dino Data Table.
8. Volume is the amount of space that an object takes up (in three dimensions). Think of what happens when a person sits down in a full bathtub of water—water spills out over the sides of the tub (see Figure 1). The volume of water that spills out is the same as the submerged volume of the person’s body. Using an overflow can, determine the total volume of the Grow-Dino. To do this, fill the can with water until the water is exactly level with the overflow spout. Position a graduated cylinder under the spout. Place the Grow-Dino in the can and catch the overflow water in the graduated cylinder. The volume of the displaced water is equal to the volume of the object. Record the volume of the Grow-Dino in the Dino Data Table. (Note: Submerge the Grow-Dino briefly; do not let it sit in the water for long, as it may begin to grow in size.)
   {11944_Procedure_Figure_1_Dino displacement}
9. Density is an object’s mass divided by its volume.

Density = Mass/Volume

Density can be a difficult concept to understand. A dense object will be heavier than a less dense object of equal size (or volume). Which of the following dinosaurs is more dense? How do you know?

Divide the mass of the Grow-Dino by its volume to determine the density of the Grow-Dino. Record the density in the Dino Data Table.

10. Place the Grow-Dino in a beaker or cup of water. Water has a density of 1 gram per milliliter (g/mL). Is the Grow-Dino more or less dense than water? If it sinks, it is more dense than water (density > 1 g/mL). If it floats, it is less dense than water (density < 1 g/mL).
11. Use a permanent marker to label a plastic zipper-lock bag with your name. Place the Grow-Dino dinosaur in the labeled plastic zipper-lock bag. Fill the bag with cold or room temperature water and seal the bag tightly. (Note: Do not use hot water; hot water may partially dissolve the Grow-Dino.) Be sure the Grow-Dino is submersed in the water.
12. Allow the Grow-Dino to soak under water for about 24 hours (overnight). Continue with step 13.

13. Pour the water out of the bag and remove the Grow-Dino from the bag. Pat it dry with a paper towel. Place the Grow-Dino on the graph paper provided. Trace the outline of the Grow-Dino on the graph paper and label this outline as Day 2 (or use a color-coded key). Trace the outline of the Grow-Dino each day for a total of five days. Label each outline as Day 2, Day 3, Day 4 and Day 5, or use a color-coded key.
14. Each day, repeat the procedures outlined in steps 2–12 submersing the Grow-Dino in fresh water at the end of each day. Measure the length, height, thickness, perimeter, area, mass, volume and density. Record all measurements in the Dino Data Table.
15. Allow the Grow-Dino to dry out and it will return to its original size. For best lab results, use a fresh Grow-Dino each time the experiment is performed.

Student Worksheet PDF

11944_Student1.pdf