This is the new updated edition of the first book in the bestselling Uncovering Student Ideas in Science series. Like the first edition of volume 1, this book helps pinpoint what your students know (or think they know) so you can monitor their learning and adjust your teaching accordingly. Loaded with classroom-friendly features you can use immediately, the book includes 25 “probes”—brief, easily administered formative assessments designed to understand your students’ thinking about 60 core science concepts.

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The purpose of this assessment probe is to elicit students’ ideas about seeds. The probe is designed to find out what students think most seeds need to germinate.

Justified list

Life cycle, germination, growth, seeds

Although there are some exceptions, the best answer is water, air, food, and warm temperature. Like other embryos of living things, the plant embryo inside a seed needs water, air, food, and a warm temperature to carry out the life processes that will support its germination and growth. The young plant embryo needs food as its source of energy and building material for growth. The food it needs is already contained within the seed. This food was made by the parent plant and stored in seeds for later use by the embryo. As the seed germinates, it uses this food for growth and energy. On some emerging seedlings, such as bean plants, you can see the cotyledons that are the remaining part of the food in the seed. This food supports the growth of the seedling’s first leaves, which need light in order to make food for the seedling through photosynthesis. The cotyledon gradually “shrivels” as a result of the food being used by the seedling to grow and develop leaves so the plant can make its own food.

Most seeds germinate best under dark conditions, and some are inhibited by light. However, there are some seeds, such as the seeds of poppies, lettuce, and geraniums, that germinate best when they are exposed to light. These seeds will often remain dormant when covered with soil.

Air is necessary for seeds to respire. Seeds must take in oxygen to use and release energy from their food. Seeds also require a warm temperature and water for the life-sustaining chemical reactions that take place in the cells of the young plant embryo to occur. However, some seeds, such as acorns, need to go through a cold period before they germinate. Too much liquid water “drowns” seeds by preventing them from taking in oxygen and causes them to rot. Some seeds can sprout in very humid air without the need for a moist surface. The right amount of water needs to be available.

Seeds can sprout without soil as long as they have a source of moisture and a surface to grow on. Sunlight is not needed by most seeds, as evidenced by the way most seeds germinate when covered by soil. Seeds have sprouted in microgravity in space. Gravity affects the ability of the sprout to send its early root structures downward, but seeds can sprout even in conditions where gravity is much less than that on Earth, such as on the International Space Station in conditions of microgravity. Fertilizers are not needed by seeds. They are used by plants once they have established roots and can take in these substances from the soil to contribute essential nutrients to the cells that make up plant structures.

Elementary Students

Elementary students typically have experiences germinating seeds and growing plants. Early experiences focus primarily on the seed’s need for water and a warm temperature. Because students often plant their seeds in soil and water them, they may not realize that soil is not necessary for a seed to germinate. Likewise, because the seeds are in soil, they may think darkness is a requirement and that sunlight would harm a seed. Investigations that involve germinating seeds under various conditions help students recognize that some factors are needed for germination and others are not. Students can eventually distinguish between the needs of seeds and the needs of the growing plant.

Middle School Students

Middle school students’ experiences investigating plants and their needs becomes more systematic. The seed’s cotyledon is recognized and investigated as a source of food for the developing embryo and seedling before it grows into a plant capable of making food within its leaves from carbon dioxide and water using energy from sunlight. As students develop an understanding that all living things carry out similar life processes and that seeds are living, they recognize that seeds also need oxygen to carry out cellular respiration. They may learn about specialized factors that can affect germination, such as the need for some seeds to travel through animals’ digestive systems in order to open the seed coat or the need for some conifers to be exposed to fire in order to release seeds. They may also investigate the concept of inhibitors where chemicals released by some plants will inhibit the germination of other seeds in their area. At this level, students should be able to distinguish between what seeds need to initiate growth and what complete plants need to function.

High School Students

Although experiences investigating germination are usually in the elementary and middle school curriculum, this probe may still be useful in determining if students retain commonly held ideas related to germination, particularly the idea that seeds don’t respire. At this level, students can measure the respiration rate of germinating seeds.

This probe is best used with grades 3–8. You may use visual props with the probe. Show students an ungerminated bean seed and a germinated bean seed, or show them a picture of a germinated seed and a seedling if they do not know what a sprout is. For older students, you may substitute the word germinate with sprout and replace air with oxygen. The probe can be extended by asking students to explain why the plant needs each of the things selected from the list.

• Driver et al. (1994) studied a large sample of 15-year-olds and found that many of the students thought that respiration occurred only in the cells of leaves of plants because those cells have gas-exchange pores. They did not see things like seeds as exchanging gases. Driver and her team’s study also revealed how students fail to recognize a seed as a living thing; therefore, they do not recognize that seeds have needs similar to those of other living things.
• Russell and Watt (1990) interviewed younger students about their ideas related to conditions for growth, focusing on germination and vegetative growth. Ninety percent of the 60 children interviewed identified water as necessary. Only a few mentioned air, gases, “food” (which to them was soil nutrients), the Sun, light, or heat.
• A study conducted by Roth, Smith, and Anderson (1983) found that students held strongly to the idea that light is always required by plants, even when presented with contrary evidence such as seedlings germinating in the dark.

Barman, C., M. Stein, N. Barman, and S. McNair. 2001. Students’ ideas about plants: Results from a national study. Science and Children 41 (1): 46–51.

Cavallo, A. 2005. Cycling through plants. Science and Children 42 (7): 22–27.

Keeley, P. 2011. Needs of seeds. Science and Children 48 (6): 24–27.

Keeley, P. 2014. Needs of seeds. In What are they thinking? Promoting elementary learning through formative assessment, P. Keeley, 39–46. Arlington, VA: NSTA Press.

Quinones, C., and B. Jeanpierre. 2005. Planting the spirit of inquiry. Science and Children 42 (7): 32–35.

West, D. 2004. Bean plants: A growth experience. Science Scope 27 (7): 44–47.

• “Seeds in a Bag” is a related version of this probe focused on the need for water and is available for grade K–2 students in Uncovering Student Ideas in Primary Science, Volume 1 (Keeley 2013).
• The part of the K–2 disciplinary core idea stating that “plants need light to live and grow” applies to plants once they grow true leaves. This does not apply to most seeds as they germinate or to seedlings, which use the food in their cotyledons before they grow true leaves and can photosynthesize. Have students argue, with evidence, whether the idea that all plants need light applies to every stage in the life cycle of a plant, including seeds.
• This probe can be followed up with an inquiry-based investigation. Have students make predictions and test their ideas with seeds that germinate easily, such as bean or pea seeds.
• Have students examine bean seeds soaked overnight. Dried lima beans work well for this. Help them see where water is taken in and food is stored for the young embryo. Rather than focusing on naming the parts of a seed, help students understand how the structure of a seed contributes to the growth and life functions of the young plant.
• An interesting question for middle school students to discuss is, “Why do seeds and nuts have so many more calories than the stems and leaves of plants”?
• Older students can investigate how environmental conditions affect the respiration rate of seeds.
• Show videos of seeds grown in space to gather evidence of whether seeds need gravity. This video from NASA, called “Space Station Live: Cultivating Plant Growth in Space,” is a useful one: www.youtube.com/ watch?v=9MfWARdoF-o.