Energy Transfer Outdoor Bucket Lab
How is Energy Transferred Within a Food Chain?
Objectives: In this lab, you will model the flow of energy through a food chain by passing a quantity of
water along a chain of students. When you have finished this lab, you will be able to demonstrate how
energy is transferred along a food chain. You will be able to model one type of interaction among
species in a food chain.
Materials: five gallon bucket filled with water, 1 plastic cup per student (with one or two pencil-sized
holes in the center of the bottom), 1 two-liter plastic bottle with the neck cut away (end container), 1
tag (sticker/labels) per student with species name, marking pencils, ruler.
Pre-lab Discussion: One of the most important concepts in ecology is the flow of energy through
ecosystems. Energy flow takes place through the food web and is often thought of as moving from
organism to organism, or from species to species, in food chains.
The energy that an organism at one level of a food chain obtains from an organism it has eaten is called
assimilated energy. Assimilated energy follows these routes:
1. Some of the energy is converted to heat during routine metabolism and various activities
(walking, running, jumping, flying, mating, etc.).
2. The rest of the assimilated energy is used to support growth or is stored until needed. This
energy becomes available to a consumer at the next level of the food chain.
Some of the energy in an organism eaten by a consumer does not become available to the consumer.
This energy is referred to as unassimilated energy. There are two major forms of unassimilated energy
in food chains:
1. Parts of consumed organisms discarded during feeding, such as bones and hides.
2. Undigested food that passes completely through the consumer’s digestive tract become
feces.
This lab uses interactions within groups of students to simulate the transfer of energy in a food chain.
You will not be rquired to transfer calories of energy to one another; instead you will transfer quantities
of water in cups. You will compare the results of the transfer among food chains for different length.
Safety precautions: Take care when transferring the water. Do not trip or fall and get hurt. Do not
drink water from any containers used in this lab!
INDOOR PROCEDURE
A. Constructing a Food Chain (should be done indoors)
1. Form as many groups as possible consisting of 1, 2, 3, 4, or 5 students each. Each group will receive
a set of tags with the names of plant or animal species.
2. Using the tags, construct a realistic food chain and decide who will wear each tag. Before wearing
your tag, write a number on it representing your link number in your group’s food chain. (Students
working alone: wear the name of a plant and write the number 1.)
3. Check your food chain and link numbers before moving on to part B.
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Energy Transfer Outdoor Bucket Lab
OUTDOOR PROCEDURE
B. Transferring “Energy” Along Your Food Chain (must be done outdoors)
1. Obtain a cup with one or two pencil-sized holes in the bottom. Links 1, 2, and 3 get cups with one
hole; links 4 and 5 get cups with 2 holes.
2. The area is labeled with rows of numbered markers. Choose a row with a number of markers equal
to the number of links in your group’s food chain.
3. Stand with your cup in your group’s row on a marker whose number corresponds to your link
number. You must be standing on your marker when water is poured into your cup.
4. Read the following instructions completely for a 3-link food chain before starting the “energy”
transfer:
a. When your teacher instructs you to start, link 1 in each group will fill his cup completely from
the 5-gallon bucket. It is up to the link 1 person to remember and record how many times he
draws water from the large bucket.
b. Link 1 will immediately go to link 2 at the second marker and pour all of the water from link 1’s
cup to link 2’s cup.
c. Link 1 returns immediately to the large bucket to refill the cup, and link 2 immediately goes to
link 3 and transfers the water. As soon as the transfer is made, link 2 returns to the #2 marker
to receive more water from link 1.
d. Continue passing water up the chain to link 3, who each time empties the water from his cup
into the end container.
e. When your teacher says “Stop,” continue passing the water already in the cups up the chain to
the end container. Then meet with your group at the end container.
5. When all groups have stopped transferring water, carefully measure the volume of water in the end
container using a ruler. Which team has the most water in their container wins!
ON A SEPARATE PIECE OF PAPER ANSWER THE FOLLOWING QUESTIONS!
Questions
1. What happened as water was transferred from one person to the next?
2. Which chain was the most efficient? __________________________ Why?
(Based upon which team had the fewest draws from the 5 gallon bucket and most water at the end.)
3. Why do you think that few food chains have more than 5 links?
4. How could your team have been more efficient in getting water to the last container?
5. Explain how this activity demonstrates energy transfer in a food chain.
6. What could the five gallon bucket demonstrate? (Hint: it is the main source of energy/water in this
activity)
7. What would happen if there were toxins in the five gallon bucket?
8. Where would most of the toxins have wound up in the end?
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