OBJECTIVES:

Students record plant measurement data over time.
Make observations about living things
Use a line graph to show the rate of growth.
Learn that seasonal changes in light and temperature impact plant growth

 
VOCABULARY:

seed, roots, leaves, sprout, stem
plant
nutrients
habitat
seasons

MATERIALS:

Plant growth models (Safariology -- Cycle of a Green Bean Plant)
Established milkweed plants
Ruler/meter stick
Garden space in sun
Water
Soil
Numbered plant pots 5 gallon
Model Measurement worksheet
Growth Data line graph (all data with example line graph)
Student Booklet

ADDITIONAL DETAIL FOR PLANT MEASURING LESSON WITH SAFARIOLOGY BEAN PLANT MODELS

MODEL 1 – SEED:  The first model shows that the life cycle of a plant starts with a seed. The purpose of the seed coat is primarily to protect the embryo (or baby) plant against such hazards as excessive drying, mechanical injury, and the digestive juices of animals (if it is eaten). Many seed coats are impermeable to water or oxygen or are hard, which helps them remain "asleep" or dormant for a long time. When the conditions are right, the dormant seed will grow or germinate.

Remember, seeds are used by other organisms as food because seeds have food stored in them. Seeds furnish humans with great proportions of food. A large part of the world relies on the grains of wheat, rice, soybeans, corn, rye, and barley. Oils and fats are produced from the seeds of coconut, corn, cotton, flax, castor bean, sesame, peanut, and soybean. Oil from the cotton seed and peanut is utilized in the manufacture of various products such as butter and lard substitutes and soap.

 MODEL 2 – GERMINATION – SPROUT AND ROOT:  The second model shows the process of germination, the development of roots and a sprout from a seed.  A root will go into the earth while the leaves go toward the light. 

 Roots help anchor the plant and draw water and minerals from the soil. Some roots form a shallow network underneath the soil surface, while others have tap roots that can go quite far down to find water and anchor the plant.

 The sprout grows toward the light because it needs light to develop a system to get food (or energy) from the sun (photosynthesis). The sprout is developing nutrients from the soil (especially nitrogen) to create chlorophyll which will help the plant make food for itself.

MODEL 3 – SEEDLING – ROOTS AND LEAVES:  The third model shows the development of first leaves and the increased spread of the roots. With the development of first leaves, the plant is considered a seedling. Most of the food produced by plants is made in the leaves. The leaves provide ample surface area for the absorption of light energy and contain many chloroplasts (which contain the molecules of chlorophyll), and it is in the chloroplasts that photosynthesis occurs.

Chlorophyll has pigments that take in energy from the sun and convert carbon dioxide and water into sugars, a process that is called photosynthesis. Photosynthesis allows the plant to feed itself and continue to grow.

 As the plant grows larger on top, it needs a larger root system.

 MODEL 4 – PLANT – STEM, LEAVES AND ROOTS:  The fourth model shows the development of the seedling into a mature plant. At this point the plant produces side stems and branching leaves, giving the plant height, width, and depth. Roots continue to deepen and spread to support the leaves with nutrients and water. Spreading leaves are essential for the plant to have the energy to make flowers and seeds to produce the next generation of plants.

BACKGROUND:

Plants are living organisms and share common characteristics with all other living things. All organisms have cells, grow, reproduce, and respond to various kinds of stimuli like temperature. However, plants have additional characteristics that distinguish them from other organisms. Plants have the ability to manufacture food (photosynthesis), have unlimited or almost unlimited growth, and have cell walls made of cellulose (used in making paper).

Students should learn that most plants are green, have roots, grow, have flowers, have leaves, live in soil, and drink water. They do not move from place to place on their own.

 The kingdom of plants includes seed plants, algae, ferns, and mosses. Plants have many cells and tissues. They make their own food using chlorophyll (the green pigment) through a chemical process called photosynthesis, which converts water and carbon dioxide into sugars, if there is enough light.

 Children sometimes mistake some invertebrate animals, like coral or sea anemones, for plants. Children reason that if it looks like a plant, it is a plant. Most children think even mushrooms are plants because they grow in the ground. When children just see a part of a plant like a bulb, root, or seed, they may not think it is a plant because it is not green.

Plants provide food and shelter for many other organisms. While this project focuses on plant growth, it also looks at plants as habitats for animals. A habitat meets all the environmental conditions an organism needs to survive. In our case, the milkweed plants students will study for plant growth also provide a habitat for the monarch butterfly caterpillar. At the end of this year, students will plant their plants in the garden, providing an increasing monarch butterfly habitat at the school.

PROCEDURE:

 PREPARATION – Set up enough milkweed in 5-gallon containers so children can work in pairs and have their own plant to measure. For a class of 24, the class will need 12 plants (but should have at least 4 to 8 additional plants in case of plant damage or death).  Plants should be located where they receive sun for a large portion of the day. They will need to be regularly watered, so a location with automatic sprinklers is ideal.

Student teams will follow the same plant throughout the year unless there is a problem. For instance, if one of the plants dies or is broken off, another plant can be used and the students will note in their journals that they have switched plants.

1.PRACTICE MEASURING WITH PLANT MODELS – Using the plant models, teachers review what happens at each stage of plant development (see Additional Detail for Plant Measuring Lesson, below, for detail of each stage).

Students will put the models in order of growth. Next, students use a ruler to practice measuring plant height. (They should use centimeters instead of inches.) They need to make sure the 0 on the ruler is down. If the plant does not show above the ground, the measurement should be recorded as 0 cm (first model). After measuring, they should enter their measurements on the plant model worksheet and draw the plant at each stage.

Review with students what measurements they have for each stage. Since they are using models, measurements should all be the same. If they get a significantly different number, they should try measuring again, as they might be holding the ruler wrong.

2.Assign a plant number to each pair of students. Students will work in pairs to measure their individual plant. Each student has a lab booklet to fill in. The lab booklets have room for students to write their observations about the plant and any organisms they find on the plant and to draw their plant.

3. MEASURING LIVE PLANTS – Go to the milkweed plants and have students measure their plant height and put it in their data booklet. To get accurate measurements, make sure students hold the ruler/meterstick vertically and do not push it into the dirt. 

Students should enter plant height in their booklet on the daily page as well as on the back page summary (see images below).

 Each pair should also let the teacher know the plant height so the teacher can record it on the teacher master list. Note:  ALL plants, including those not assigned, should be measured each time and measurements added to the teacher master sheet.

 4.Students should also draw their plant and add any observations or questions to their booklet. This gives them practice with scientific observation and writing. If they need help with how to observe, they can count the leaves, look for any insects, and notice any holes or other imperfections.

 If students have problems knowing what to write, the teacher can provide sentence frames.

5. GRAPHING THE DATA – Eventually students will plot the plant height data on a line graph. This should be done at least every three months. At the end of each graphing event, you can compare the data sheets of each plant. Students should look for patterns. Are they all growing fast during similar months? Are they all slower in different months? Do any have particular problems like insects eating them? Did that affect their growth?