Developed by Dhruba Naug and Amanda Stammer working with students of Bennet Elementary School, Fort Collins

This experiment is designed to introduce elementary school students to a fundamental concept in animal behavior as well as basic experimental techniques in science and ideas about probability, randomness and non-randomness. Students will learn the difference between experimental studies and observational studies and the advantages and drawbacks of each. They will also learn the use of probability and how it is a central idea in science and is routinely used to understand and predict animal behavior. They will learn how to design an experiment, collect quantitative behavioral data, analyze it and interpret it to learn about possible adaptive advantages of a behavior.

Detailed step-by-step instructions are included in the instructor’s packet. This page is designed to help instructors prepare for the experiment.

The experiment is organized into three parts:

1. Discussion and Questions: This segment is intended to assess the students’ knowledge of how scientists make observations, pose questions and form hypotheses as well as introduce them to the different ways animals might search for food. Using situations the children are familiar with about searching, such as the Easter egg hunt, discuss the challenges an animal is likely to face searching for food in a big world. Encourage them to form hypotheses of their own about how they search for eggs on Easter and if the same strategies might also apply for animals. An important concept that can be introduced here is whether one should change the search strategy upon locating a food item.
2. Mock Search by Students: This segment will help the students design a set of simple rules that can define a search strategy and implement it to get familiar with the idea of recording data about a search and explore the concepts of randomness and non-randomness. The students will trace a random search and a non-random search on a grid and observe their relative success in finding food in different types of resource distributions. This exercise is designed to give them more insight into the advantages and drawbacks of different search methods under various environmental conditions.
3. Search behacior of housefiles: The students will observe the behavior of houseflies as they search for food on a grid, quantify their movement patterns and interpret the search pattern. Working in groups, students will assume different “research roles” as observers and recorders in order to get the most complete and accurate picture of the behavior. This segment incorporates teamwork with the basic principals of scientific research. The students will calculate parameters of the search, plot the data and discuss their results with other groups to form their own conclusions about the behavior exhibited by the fly.

The Basics:

Budget: $20-$30

Age: 4th to 6h grade. With modifications, 7th and 8th grade (suggested modifications: more questions about probability and mathematical properties of randomness)

Time: 2 hours

Materials:

• Houseflies (see more in preparation)
• Sugar solution (50% by weight)
• Eye droppers
• Arenas for observation (we used 6 cm square petri dishes)
• Grid diagrams covered with plastic or overhead sheets to serve as food patches(template)
• Visual blockers for observation arenas (we built them out of poster board)
• Rulers
• Stopwatches
• Coins
• Theoretical food patches (template A) (template B)
• Student Experimental Packets
• Instructor Packet(s)

Preparation:

• Flies
  • Obtaining and preparing the flies is by far the most time consuming component of this experiment, but it is by no means difficult.
  • Many online science supply stores sell kits that can be used to raise numerous flies. This system can supply a virtually endless supply of flies and is usefull if you will be performing this experiment more than once.
  • The wings of the flies can be removed to encourage them to walk on the grid rather than fly. For this, capture a fly in a vial and chill it in a refrigerator until it is immobilized. (Flies are pretty resilient but it is still possible to freeze-kill them, so it’s best to check them often and take them out of the freezer as soon as they are completely still) Once the fly is “asleep” you can cut the wings off with a small pair of scissors. The flies can “wake up” rather quickly, so it’s best to do this one at a time and place each fly in an arena immediately after its wings have been cut.
• Instructors
  • If working with younger children, it is a tremendous advantage to have an adult instructor work with one group of 4-5 students. However, this is adjustable depending on the age of the students, the number of students, and the number of instructors (or parent volunteers) that are available.
  • If instructors are not educators by profession, it may be usefull to meet with them beforehand and explain the experiment by reviewing the Instructor’s Experimental Packet.
• Sugar Solution
  • Mix equal parts by volume of water and sugar.
  • Place a single drop of sugar solution on a random square on the fly grid a little before beginning the fly search segment of the experiment making sure it does not dry out.
• Time
  • We completed this experiment in two hours while working with fifth graders.
  • It is advisable to adjust this expectation depending on age and aptitude of the students