Exploring Our Fluid Earth

Materials

• Six thermometers or digital temperature probe sensors
• Six aluminum foil packets
• Stopwatch
• Colored construction paper
• Scissors
• Tape
• Rubber bands
• Water
• Graph paper

Procedure

A. Hypothesis Testing

1. Using an aluminum foil packet and thermometer to simulate an individual reptile body, design a set of experiments to test the following three research questions:
   
   1. What effect does habitat or substrate material have on reptile body temperatures over time? For example, do lizards warm faster on rocks or on grass?
   2. What effect does skin color have on reptile body temperatures over time?
   3. What effect does sunlight intensity have on reptile body temperatures over time?
       
2. Write out your group’s experimental design, listing materials and procedures. Develop a hypothesis for each research question. Ensure that your experiments are specifically designed to address each hypothesis and research question. Assign specific roles and tasks to each group member.
    
3. Begin your experiments. If you notice problems with your experiments, discuss them with your group. Consider modifying your experimental design before continuing.
    
4. Record all collected data in a table. Plot your data in a separate graph for each experiment. Select the type of graph that will present your data most accurately.
    
5. Analyze your data. Answer questions 1–4 below.

B. Simulating Reptile Behavior: Part I

1. Reptiles in the real world regulate their body temperatures by using a combination of behaviors. They warm and cool themselves in an attempt to maintain body temperatures within some optimal range where internal chemical processes (e.g., metabolism or processing of food and body wastes) are most efficient. In Part A of this activity, you simulated a variety of different reptile behaviors to determine their effects on body temperatures.
    
2. Use your findings from Part A of this activity to plan a single combination of behaviors that will produce a target body temperature of 25 °C after 10 minutes.
    
3. Record the combination of behaviors your model reptile will use: substrate type, skin color, and sunlight intensity.
4. Using the same foil packet and thermometer apparatus from Part A, begin your simulation and record temperature readings every 30 seconds until reaching 10 minutes total time.
    
5. Plot your temperature and time data on a graph.

C. Simulating Reptile Behavior: Part II (optional).

1. Consider the behavior of reptiles in the real world. Reptiles can move in and out of shade and rest on a wide variety of substrates. Some species of reptiles can change their skin color at will. Examples of color-changing reptiles include chameleons, anoles, and some snake species.
   
   1. Use a combination of reptile behaviors to produce a body temperature that is closest to a fictitious optimal operating temperature for our aluminum foil packet reptile model: 25 °C.
   2. Modify behavior to maintain this ideal temperature for as long as possible throughout the exercise.
       
2. Record temperature readings from your simulated reptile model for every 30 seconds for 10 minutes. Add notes on the reptile behavior employed during each time 30-second time interval.
    
3. Plot temperature data on graph paper. Draw a smoother line between data points.
    
4. Using the smoother line on the graph, estimate the number of minutes the temperature is 25 ± 1 °C. This time within the reptile’s optimal temperature range represents the amount of time it can complete other behaviors such as hunting, courtship, mating, territorial defense, migration, and predator avoidance. Compare your findings with those of other groups in the class.