Curricular Materials to Accompany the
McIntosh Apple Development Poster
Distributed by the Education Committee of the Botanical Society of America
Posted March 2001
Grade Levels: 6-8; 9-12
|Abstract: Many plants rely on wind to carry their fruits
or seeds. In this activity, students explore the mechanism of wind dispersal by creating
their own model fruit and evaluating the relationship between the fruit structure and its
At the end of this exercise, students will be able to:
- Identify different types of fruit and seed
- Design fruits/seeds so that they will
disperse effectively in the wind
- Measure the distance the fruit/seed travels
and estimate the time aloft
- Summarize their data in graphical format and
analyze their results.
- Determine if there is a correlation between
the distance a fruit or seed travels and the amount of time aloft
Dispersal of seeds is important for the continued
survival of a plant species. If plants grow too closely together, they compete for
light, water, and soil nutrients; therefore, seed dispersal is a way to distribute
offspring. In flowering plants like apple trees, one or more seeds are housed within
a fruit which is the portion of the apple that we eat. Sweet fruit like apples are
eaten by animals that disperse the undigested seeds. In contrast, some plants have
fruit that remain on the plant and disperse only the seeds. In either case, plants
have evolved different dispersal mechanisms. Some fruits can be carried by water,
like the coconut. Burdock fruits have hooks that attach to and are dispersed by
animals. Dandelion fruits are suspended from feathery "parachutes" that
are carried on the wind. The fruit of maple and ash trees have wings that let them
float on air. This activity is a fun way for the students learn how fruit or seed
size and shape influence their ability to disperse by wind. Students design their
own fruit or seed and measure two important qualities that enhance the ability of it to
disperse in the wind: distance travelled and time aloft.
- fruit and/or seed examples from sunflowers,
dandelions, maple trees, coconuts, apples, peas, nuts, etc. (you may choose many different
types or the same for each student).
- supplies to construct artificial
"fruit" or "seeds" (paper, tape, sissors, glue, pipe cleaners, etc...)
- window or large fan
- meter stick or tape measure
- stop watch
- Set up lab stations with different types of
fruits and seeds at each station (or a group of fruits/seeds with similar methods of
dispersal). Have students record the fruit or seed type, type of dispersal,
and sketch the fruit/seed.
- After the students have viewed each fruit or
seed, review what they have observed. Ask questions that have students consider the
relationship between the fruit or seed structure and its mode of dispersal.
- Distribute one sunflower fruit (commonly
called "sunflower seeds") and supplies to construct a wind dispersal mechanism
for the fruit. Explain to the students that they will be placing their completed
"fruit" in front of the fan and measuring the distance it disperses. This
is a competition to determine which travels the furthest. In addition, they will be
measuring the maximum time the "fruit" remains in the air--the maximum time
- After they have created their
"fruit", the class will evaluate their dispersal characteristics. Set the
fan up on a desk blowing horizontally across the room. Establish a standard drop
site above the fan and set a tape measure along the floor beneath the fan. Each
"fruit" should be dropped by the student three times and the average used in
their results. Alternate students in charge of measuring the distance from the fan
as well as measuring the time the "fruit" is in the air.
- For the second part of the experiment, have
the students drop their "fruit" from a standard height (2 meters) while
measuring time spent aloft with a stopwatch. Repeat so that each student does three
trials of this experiment. Calculate the average of the three trials and record in
- After all the data has been collected, the
students should graph the distance traveled and the time aloft. Have students graph
all of the classes data.
- The students should determine if a
correlation exists between the maximum time aloft and the distance traveled from their
- Discuss with students why the winner's
"fruit" traveled the furthest and lasted the longest in the air.
- What design did the winning "fruit"
have? Why was this a paricularly effective disperser? That is, what may have contributed to
the win? Was it built better, stronger, lighter? How much
paper or tape did the student use? Do these affect the weight of the
- Does it matter how the student dropped
the "fruit" in front of the fan?
- What other factors in nature
contribute to wind dispersal?
- Does it matter if the plant is higher from
the ground? In an open area?
- What are the advantages of wind dispersal?
Are there any disadvantages?
- Is wind dispersal more likely in dry or
Introductory plant biology books will discuss
fruit and seed dispersal. Several are listed below.
- Burnie, David. 2000. Plant. Dorling
Kindersley Eyewitness Books, New York.
- Raven, P.H., R.F. Evert, S.E. Eichhorn. 1998. Biology
of Plants. Worth Publishers Inc., New York.
- Stern, Kingsley R. 2000. Introductory
Plant Biology, 8th ed. McGraw Hill, Dubuque, IA.
- Uno, Gordon, R. Storey, and R. Moore
2001. Principles of Botany, 1st ed. McGraw Hill, Dubuque, IA.
- Vogel, Steven1981. Life in Moving Fluids,
the Physical Biology of Flow. Princeton University Press, Princeton, NJ.
This activity was developed and edited
by Amy Russell and Steven Rice, Department of Biological Sciences, Union College,