Children s Ideas Children come to science instruction with a diverse set of ideas about natural objects and events and how things work. These ideas are fairly tenacious after all, they were developed based on the student s own experiences. These ideas, though, can be erroneous, illogical or misinformed. These erroneous understandings are termed alternative conceptions or misconceptions 1. Alternative conceptions are not unusual. In fact, they are a normal part of the learning process. We quite naturally form ideas from our everyday experience, but obviously not all the ideas we develop are correct with respect to the most current evidence and scholarship in a given discipline. Here is a list of what we know about alternative conceptions: Alternative conceptions that learners bring to science instruction cut across age, ability, gender, and cultural boundaries. Alternative conceptions are tenacious and resistant to change. Alternative conceptions often parallel explanations of natural phenomena offered by previous generations of scientists and philosophers. Learners prior knowledge interacts with knowledge presented in formal instruction, resulting in a diverse set of unintended learning outcomes. Alternative conceptions have their origins in diverse sets of personal experiences including direct observations and perceptions, peer culture and language, and in teachers explanations and instructional materials. Teachers often subscribe to the same alternative conceptions as their students. Instructional approaches that facilitate conceptual change can be effective classroom tools. Dealing With Students Alternative Conceptions: Instructional strategies that can lead to change in students' alternative conceptions (misconceptions) and to learning of new concepts and theories: 1. Ask students to write down their pre-existing conceptions of the material being covered. This allows you to overtly assess their preconceptions and provides them with an opportunity to see how far their understanding has come after learning the new concepts. 2. Consider whether student preconceptions could potentially be beneficial to their learning process. It is possible that preconceived notions about material, even if not entirely accurate, could provide a base from which to build knowledge of new concepts. For example, using students' correct conceptions and building on those by creating a bridge of examples to the new concept or theory is a beneficial strategy to help students over misconceptions. 1 We like to call them alternative or naïve conceptions rather than misconceptions. They aren t wrong from the learner s point of view they are what they ve developed to explain their experience. Calling them alternative conceptions honors the leaner s life experience. Our jobs as educators is to provide experiences that help them create more sophisticated understanding. Children s Ideas Page 1
3. Present new concepts or theories that you are teaching in such a way that students see as plausible, high-quality, intelligible and generative. 4. Use model-based reasoning, which helps students construct new representations that vary from their intuitive theories. 5. Use diverse instruction, wherein you present a few examples that challenge multiple assumptions, rather than a larger number of examples that challenge just one assumption. 6. Help students become aware of (raise student metacognition about) their own alternative conceptions (misconceptions). Following are common ideas children in grades K-6 have about Life, Life Cycles and Shape and Structure of Organisms. This material is included to help you consider why a child would be likely to believe this and what evidence might help the student develop more sophisticated ideas. 1. Plants do not reproduce in the same sense that animals do. Plants and animals both reproduce sexually with sperm and egg uniting to form the first cell of a new individual the fertilized egg. There is an equal contribution of male and female hereditary material, just as in animals. Children may hold this idea because they associate reproduction with the act of mating in animals and they do not observe females or males in plants. 2. Plants are neither male nor female. Plants have male and female reproductive structures. The male structures produce sperm and the female structures produce eggs. In many cases, both male and female reproductive structures occur on the same individual (in flowering plants, they are found in the flower). In other cases there are individuals of separate sexes. Children may hold this idea because they don t observe what is familiar to them as a female or male and they don t understand that plants reproduce sexually. 3. Seeds are not alive, but can give rise to a plant. All living things arise from other living things. Seeds are formed from a fertilized egg, which is a living cell that arises from the union of two other living cells sperm and egg. These cells themselves arise from living cells there is no discontinuity in this process. Seeds demonstrate all the characteristics of life: they re made of cells, they have a life span, they use matter and energy, they respond to their environment, and they carry DNA. 4. Seeds contain a tiny adult plant already formed inside. Children may hold this idea because they do not readily observe developmental differences between a sprout and an adult one is a miniature of the other. Seeds, however, do not contain tiny adult plants; they contain a plant embryo that has developed from the fertilized egg. In larger seeds, this embryo can be observed by dissecting the seed. Given appropriate care, the embryo can be seen to go through different developmental stages, from sprout to adult. Children s Ideas Page 2
5. Seeds use the sun for energy to sprout. The embryo inside a seed depends on food stored in the seed to support it until it can begin to photosynthesize as a sprout. If you take this food source away before a seed sprouts, the plant will not survive in sunlight alone. During the sprouting process, a small amount of food begins to be provided by photosynthesis. Once the sprout is established, photosynthesis becomes the sole supplier of food. Children observe that seeds sprout in the presence of sun and water. If they don t know that seeds store food, it s understandable that they consider the sun as the seed s energy source. 6. Flowers are for insects to feed upon. Children often think that one life form exists to serve another. When they observe insects feeding on flowers, this may be a conclusion. Life forms, however, do not have a purpose ; they have functions, which may include being beneficial to other life forms. Flowers do function to provide food for many insects, but the sole function of a flower for the plant is reproduction. 7. Fruits are always sweet, fleshy products of plants. A fruit is the ripened ovary formed from a flower. A fruit contains the seeds. Many things that children consider vegetables are actually fruits, including pea pods, cucumbers, peppers, and tomatoes. Nuts and pods are also fruits. 8. If it moves, it is alive. Many things that move aren t alive, such as cars, clouds, and flowing water. The living things that are most familiar to children are likely to be animals that move. Since they consider animals to be alive, they may associate the characteristic of movement with life. 9. If it seems to move by itself, it s alive; if it s moved by something else, it s not alive. A shadow moves by itself, but it s not alive. Fire also moves by itself. Once children recognize that there are non-living things that can be moved by an external force like clouds moved by the wind, or a bicycle pedaled by a person, they may make the finer distinction that something is alive only if it can move itself. 10. If it makes light or a noise, it s alive. A burning candle and a flashlight make light but are not alive. A ringing bell and a piano make noise, but are not alive. Younger children may believe this because they associate doing something with being alive. 11. It s not alive unless it s doing something. Children s Ideas Page 3
A potato doesn t appear to be doing anything, yet a potato is alive. If you plant a potato in a suitable environment, it will grow into a potato plant. At the cell level, all living things are constantly doing something, even if this can t be detected. Children may hold this idea because they connect life with activity, particularly movement. In contrast, familiar examples of nonliving things like rocks or books don t demonstrate activity. 12. To be alive, something has to breathe. Not all living things breathe in the same way that animals do inhaling and exhaling. Plants, for example, do not breathe. However, the cells of all living things do take in and release gases. Children s firsthand experience of the need to breathe and their observations of other animals may lead them to think that all living things have to breathe. The process where plants take in CO2 and release O2 during photosynthesis is sometimes likened to breathing, so children may equate it with breathing. 13. Growth is not a pre-requisite of life. One characteristic of life is a life span, which includes a period of growth. From a living beginning as a single cell, all life forms can be observed to grow even organisms that are made of only one cell. Growth occurs as cells get bigger and, in multicellular organisms, as cells divide to form new cells. This idea may arise because children observe some living things when they are no longer growing. A full-grown plant, for example, may not appear to grow. 14. Objects like seeds, spores, eggs, and pupae are not alive, but they can give rise to living things. Because seeds, spores, eggs, and pupae appear to be doing nothing, many children think they re dead or nonliving while at the same time believing that they can give rise to living things. Just as all cells come from an existing cell, all life comes from something that is alive there is no discontinuity of life during a life span. Seeds, spores, eggs, and pupae represent the living beginnings of a life span and have the potential for growth, development, reproduction, and death. They also demonstrate the other characteristics of life. This makes them alive. Children may believe this because they do not observe any activity in these objects, and they can t see the developing organism inside. 15. Plants and fungi are not alive. Because plants and fungi don t move, some children think they aren t alive. Nonetheless, both plants and fungi demonstrate the characteristics of life. They are built from cells, have life spans, require matter and energy, respond to their environment, and carry the hereditary material DNA. Children who consider movement as a requirement for life may hold this idea. In this case animals may be considered to be the only things that are alive. 16. Plants have a different kind of life than animals. Children s Ideas Page 4
Plants and animals differ in many ways. However, the characteristics of life apply equally to both groups of organisms. Each is made of cells, has a life span, uses matter and energy, responds to its environment, and carries the hereditary material DNA. Children may think this because the observable differences between plants and animals seem to make them opposites of each other. This also may be reinforced by placing the emphasis on differences while teaching about these groups of organisms. 17. Young children do not volunteer reproduction as a criterion for life. Reproduction is a characteristic that defines life. Reproduction, however, is not an immediate observation that young children are likely to make of living things. Once they have enough experience observing the production of offspring by parents and see themselves as a part of this pattern, they are more likely to add this to their definition of life. 18. Reproduction is synonymous with mating. Children probably hold this idea because they are most familiar with an animal model for reproduction where mating involves the act of copulation. Not all life forms mate to reproduce. Even life forms that involve the union of male and female sex cells do not necessarily mate plants are a good example. And, there are even animals that don t mate. Female fish and frogs, for example, deposit their eggs in the water where the males fertilize them externally. And many aquatic invertebrates for example, sponges, jellyfish, starfish, and clams shed sex cells into open water where fertilization occurs. 19. The environment is the cause of variation among individuals. Individual variation exists even when the environment is kept constant. Children readily observe individual variation. If they have not been introduced to the basics of heredity (i.e., DNA and genes), then they are likely to account for individual differences by considering what might vary around that individual: the environment. 20. The environment is more important than genes in causing variation. If the environment were more important than genes in causing variation, even subtle changes in the environment would be expected to have an impact on any number of traits. Yet despite constant changes in the environment, very little change occurs in individuals as a result. If children have a basic understanding of the genetic basis of heredity, they may still believe the environment has a greater role in causing variation because they have a hard time believing that there is so much variability resulting from genes alone. Since they can t observe variation in genes, and they can observe variation in the environment, they may conclude that the environment has a greater impact. They may also have had experience manipulating conditions that have dramatic effects on plants this could influence their early ideas about the environment vs. genes. Children s Ideas Page 5
21. Adaptation involves individuals changing in response to their environment in order to survive. In an evolutionary sense, adaptation occurs over many generations and involves change in a population. It is observed when some variation in a trait becomes more common with each generation. This is different than the responses that an individual might make in order to survive during its lifetime. The first meaning that children have for the word adaptation will often involve a change that an individual makes. To build an understanding of adaptation as an evolutionary concept, children might be encouraged to consider two or more generations of a population that have changed in ways that make each successive generation better suited to its environment than the previous one. 22. Individuals adapt out of need or desire. Adaptation has a genetic basis. Need or desire to change (i.e., vary) in some way in order to survive has no impact on the information that is already present in an individual s genes. This reflects anthropomorphic reasoning: People can consciously decide to change, therefore change comes about because of need or desire. One way to counter this idea in terms of evolution is to encourage children to think about other life forms that cannot think like plants. 23. Traits that are developed during an individual s lifetime can be passed on to their offspring. In order for traits to be passed to offspring, they must be coded in a parent s DNA and then transferred during reproduction. Traits that are developed during a lifetime, such as a muscular build or the ability to speak several languages, do not have an impact on one s DNA. Children who understand that offspring inherit traits from their parents may extend this idea to traits that a parent develops during his or her lifetime. It may be difficult to challenge this thinking with traits that have a genetic basis one s build, for example. Encouraging children to think about someone who has dyed his or her hair or who has learned how to swim may help challenge this thinking. Children s Ideas Page 6