That’s My Baby! (A Life Cycle Unit Using FOSS Structures of Life)
By Tena Brown, Wengert Elementary School, Las Vegas, Nevadalarge

This young scientist measures the height of his bean plant.

These were just a few of the remarks I overheard from my third-grade students as they examined and measured their bean plants during our life cycle investigations as part of the FOSS Structures of Life Module. They sounded like parents of toddlers as they bragged about and compared their plants with others before documenting the growth and development.

“What's this green stuff on my roots?”
“Do I need to add more water?”
“Can I eat the bean?”

Students had many questions as they watched the changes that took place in their plants.

Someone observing my class (without looking at my lesson plans) may have thought we were studying only science all day, but reading, writing, and math were integrated into the Structures of Life study. This module takes my class at least six weeks to complete. I use our science book during our reading block, we maintain a science journal as part of our writing, and we make various measurements to reinforce our math. The unit culminates with a 6- to 12-page report on one of the three life forms we study, which contributes to a grade for science, reading, and writing. We investigate plants and crayfish, and I usually add hatching chicken eggs and raising silkworms. I have found that the timing of the life cycles for our plants, eggs, and silkworms is very consistent and easy to plan for.

Students put together their own seed sprouting containers. I also place enough bean seeds for the entire class into the sprouter so they will be ready at the same time as the student sprouts. I add alfalfa seeds to the top level of the sprouter so students get a chance to taste the sprouts. Most of my students have never tasted alfalfa sprouts, and none of them has watched them grow. We predict how long it will take for the seeds to sprout, and students are always surprised at how soon the tiny roots appear. I grew up in the country and love to garden, but the Las Vegas environment is not favorable for backyard gardens. It warms the cockles of my heart to watch children become excited about plants bursting forth from their small, hard enclosures.

A successful life cycle results in a green bean, ready to eat!

I want my students to witness the entire life cycle of a plant. We document the properties and record group observations in our science journals. There are hydroponic containers in the Structures of Life Module, one for each Notes from the Field...group of four. I decided I wanted each student to have his or her own inexpensive hydroponic container. I use two-liter soda bottles for many projects in my class, so it wasn't long before I realized that I could cut the top portion off, craft a piece of Styrofoam plate to fit inside as a float, and thus provide all of the students with their own container, all with recycled materials.

I encourage students to analyze the parts of the FOSS hydroponics container that provide for successful plant growth as I help them design their individual containers. By looking at the features of the container that were necessary for success (clear plastic, holds water, enough depth so the plants have enough water) and discussing what available materials have the same features, the students soon suggest the two-liter bottles.

I make a short cut from the shoulder of the bottle down to the bottle's label. Students complete the job of cutting the top off and removing the label. They also cut a slice of Styrofoam plate so that it would fit inside the bottle, poke a hole in the center of the piece of plate with a pencil tip, and make a cut to the hole. They fill the container half full with water and set the sprout inside. A piece of masking tape on the side for a label ensures that each student always examines his or her own plant.

Tena's students grow beans in individual hydroponic containers that they construct from two-liter soda bottles.

The sprouts are usually ready for the containers about one week after they germinate, when they have enough stem to slide into the Styrofoam. The sprouts have a better chance of surviving if I place them in the Styrofoam so that the stem just above the roots is held firmly. I have tried to raise the corn, pea, and sunflower plants hydroponically, but only the beans work well. Students start documenting the growth as soon as their sprout is in its container. I have modified the student sheet to provide more room for students to write. Students know that it is important to always record the date, the height, and changes and to make a drawing. The plants are kept under a grow light between observations. Students make their second entry two or three days later. It always amazes students to see how much change happens in the first two days. We discuss the shapes of the leaves and the difference between the first two leaves and those that follow. I encourage students to draw pictures as accurately as possible. Students use magnifying lenses to observe the hairs on the leaves and their veins. They are often tempted to lift the plants out of the water, but I try to discourage them from doing this. I encourage students to use correct vocabulary when writing about their seedlings and labeling their drawings.

Students watch their plant go through the four stages of life: birth (germination), growth and development, reproduction, and death. I always hope that the last stage won't happen until after they take their plant home, but it is an inevitable stage of the process. As the bean plant grows taller, it will need to be staked. I roll a sheet of recycled newspaper into a tight roll, securely taping it to the side of the container, and use yarn to tie the plant to the stake when necessary. The FOSS kit contains a packet of nutrient powder to provide nitrogen and other water-soluble nutrients for the plants. After diluting the powder, I usually add a "blop”to each student's container. I expect each student to record the addition of the nutrients and their purpose in their documentation. One of the great things about growing the plants in a clear container is that the roots are clearly visible. It won't take long before blossoms appear, followed by the tiny bean as the blossom dries and drops off. This is a good time to look at the parts of a flower and how different flowers' pistils and stamens look. Students love the chance to take a flower apart and examine the interior. Because not all plants reproduce from seeds, I bring in a potato, an onion, and a strawberry to discuss how plants can grow from tubers, bulbs, and runners.

My students write a report on the eggs, crayfish, silkworms, or their bean plants. Their reports include photos and illustrations, graphs showing rate of growth, and a section of research. The cover page and outline are computer-generated; the rest of the report is handwritten. Besides the science, I grade the reports for language. I have had students and parents tell me years later that those reports are still cherished. This is their first major report, a milestone for third grade.

Tena Brown taught at Wengert Elementary School in Las Vegas, Nevada, when she conducted these investigations with her third-graders. You can contact Tena at Tbrowntena@aol.com.