Corn vs. Soybeans - Part 1
How are corn and soybeans different? There are countless differences between corn and soybeans. In this
activity, you will look at a few of these differences. You will also see how they affect the growth and uses of
these plants.
Look at one corn seed and one soybean seed. Use these two seeds to answer the questions below.
1. Describe the corn seed.
2. Describe the soybean seed.
3. How are these two seeds different?
4. How are these two seeds the same?
5. Each seed has a part called a cotyledon that stores food. One seed is known as a monocot seed and
the other is known as a dicot seed. Which seed do you think is a monocot seed and which seed do you
think is a dicot seed? Why do you think this?
A “window grower” has been prepared for you to observe differences in the growth of corn and soybeans.
Inside to grower is a substance called vermiculite that will hold moisture for the seeds. Between the outside
of the grower and the membrane are the seeds. The grower is kept in a warm place out of direct sunlight.
You will be using this window grower to observe the growth of these seeds.
6. What do you think the vermiculite simulates in this grower? Why?
7. Why do you think this grower is kept out of direct sunlight?
8. What do you predict you will observe about the seeds in the next few days?
9. Do you think you will see the same thing from the corn and soybean seeds? Why?
Corn vs. Soybeans - Part 2
The day before, you observed the outside of a corn and soybean seed. Today you will observe the inside. You
need to get a split corn seed and a split bean seed, a paper towel, and a magnifying glass. Once you have all
these things at your station, lay out the halves of the seeds next to each other so you can examine them.
1. Take a picture of inside of the soybean seed. Then take a picture of the inside of the corn seed. Be
sure the picture is zoomed in so you can see all the inside parts of each seed. You will be labeling each
of these pictures later.
2. You need to locate each of the following parts of each seed. You may need to use the magnifying glass.
The picture below will also help. Label each of these parts in your pictures that you took.
a. Embryo – the undeveloped plant
b. seed coat – the outer covering of the seed that protects the embryo from insects, disease, and
damage
c. cotyledon – stores food for the developing embryo; the first part of the plants that emerges
from the soil
d. epicotyl – forms the stem of the plant; growing point of the plant
e. endosperm – source of energy (starch) and protein for the germinating seed
3. Remove the seed coat of each seed and place it on the side of your paper towel. Remember that the
seed stores food for the embryo to start to grow. Much of this food is stored in the form of starch.
Which seed do you think has more food storage, corn or soybean? Why?
4. To see if your prediction in number 4 is correct, ask your teacher to place a drop of iodine on each
seed. Iodine causes a substance to turn blue-black color if starch is present. Which seed had more
starch – corn or soybean? How did you know?
5. Why do you think one seed had more starch than the other?
6. How do you think the amount of starch in the seed will affect the growth of the seed?
7. Look back at your predictions from Part 1 (questions 8 and 9). Does anything about your predictions
change? Why or why not?