Let Us Go Back to Nature Study Dorothy L. Gabel Indiana University, Bloomington, IN 47405 The Second International Studv for the Evaluation of Educational Achievement ( 1 ) conducted between 1983 and 1986indicatesthat the United States ranked eiahthout of 15 countries in science achievement for 11-year-old children and 13th out of 18 for 14-vear-old children. Yet an examination of the chemistry content of both textbooks and tradebooks deemed appropriate for children at the presecondary level would make one think that the United States would place first in such surveys. Although the cause for the low science achievement of United States youngsters can be attributed to many factors, might one of these be that the content of the books is too advanced and is inappropriate for the age level specified? Can children under the age of 11 really understand polar molecules, the kinetic molecular theory, balanced equations, and the difference between heat and temperature? All of these topics are found in hooks written for children in grades 1-5. But when children are asked about these topics, they reveal a naive understanding of what has been taught. For example, when a child is asked why water becomes cold on the addition of calcium chloride, he or she is likely to reply that it is "giving off cold". If chemistry instruction is to be improved, we must understand how these naive conceptions, or misconceptions, are acquired. Ways Mlsconceptlons Are Acqulred
There are three obvious wavs that persons acquire misconceptions. They acquire them from nature, fromianguage, and from instruction. First, consider children's observations of the physical phenomena around them. Sometimes the senses "deceive" them. For example, if a child is sitting on an unholstered chair that has metal lees in an air-conditioned room, when asked whether the me& or the cloth is colder, the child will say that the metal is colder. To the child who has never placed a thermometer on the metal and on the cloth to make the com~arison.the metal feels colder. In other cases, children give a logical reason to a new situation to which it does not a.. p ~. l vFor . example, . . consider an experiment on measuring the temperatures of equal volumes of water bv fourth araders. Children obtained separate samples of hot and cold aater from two large bucketsblaced in front of the classroom. Each pair of children filled two vials onethird full of water, hot in one and cold in the other, and measured the temperatures that were then recorded on the hoard. When the children were asked how thev would reoort the temperature of the water in the bucket; even t h b h children at this age usually have an uncanny sense to select the median value or the mode, one boy insisted that the temperature would be the hiehest one reported. When asked to explain his selection, his reply was, "There is more water in the bucket than in the vial so the temperature must be higher." He was so convinced that his hypothesis was correct that after he came to the front of the room and placed the thermometer in the hucket of hot water, he waked a long time for the temperature to go up! Chemists should not be surorised at children's naive conceptions about matter and the'changes it undergoes because thev too believed in "naive theories" such as ~hloeistonuntil ratier recently. Furio Mas, Perez, and ~ a r r i(2) s iave shown
that adolescents' conception of gases parallels that of h i s totle. A second reason why children acquire misconceptions is because words are used differently in everyday usage from their scientific usage. Almost everyone has heard the expressions, "the coffee is strong", "sugar melts in my mouth", or "the toast is burnt". When science books are not carefully written they may containstatements suchas "heat moves up the rod" or "molecules expand on heating". Chemistry teachers may make a statement such as "observe the substance in the test tube" when the test tube contains a mixture of substances. Even a p o ~ u l a rafter-dinner game perpetuates misconceptions whkna question such as;'~o melt in vinegar?'' is not considered a trick question and the correct answer is given as "yes". This inadvertent improper use of vocabulary does not confuse naive learners. Instead thev acauire the nonscientific meanine of the words and use them in this improper way in their science classes. Acouisition of misconce~tionsthroueh formal instruction is a third reason why chiidren have &isconceptions. This occurs when (1) children are presented concepts in two few contexts or (2) what is presented is beyond their developmental level. The learning of the concept "volume" illustrates how limiting the context creates distortions of it. Although children in the first and second grades are generally presented with the idea that the volume of a container is its capacity or the amount of space that an object occupies, once children have' reached the grade level where mathematics is associated with the meanine of volume. thev memorize that volume is length times widih times he;ght.~s adults they continue to a ~ ~ this l v definition indiscriminatelv to other eeometric si&es (3)! In order to understand the concept of volume or any other concept that is so fundamental to inderstanding chemistry, such as mass, changes of state, solutions, and chemical and physical changes, students need a myriad of hands-on experiences beginning from early childhood and continued throughout their precollege education. To have them be able to repeat that the freezing point of water is 0 'C and the boiling point is 100 OC, but to think that all ice exists at 0 O C or to be unable to tell whether another substance is a solid, liquid, or a gas at a given temperature when given its freezing and boiling points is inexcusable. It shows that students have memorized trivia. The other reason why formal instruction aids in the development of misconce~tionsabout chemistrv is that the content that is sometimes presented to children in the elementary classroom or in science textbooks is beyond their comprehension and their developmental level. Most children in the elementary school are in what Piaget calls the concrete operational stage of development (4). The implication of this for teaching chemistry at the elementary level is that children need to work with concrete ohiects rather than learn about models and theories. Yet an e;amination of textbook series for use in erades K-6 shows that most textbook series introduce atomsand molecules by the second or third grade. In order to make atoms and molecules "concrete", some teachers have children make marshmallow and gumdrop
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models. Although well-meaning, this use of a concrete model does not make an abstract theory (the kinetic molecular theory) concrete for young children because it is beyond their mental caoacitv to make the connection between the analogue and tce thLoretical construct. In practice, it may confuse them even more and create other misconceptions! Chittenden (5),in a study of 8-year-old children, found that manv had the view that the roundness of the earth could be compared to a round plate or to an open umbrella. Even though the earth is less abstract than atoms and molecules, childien were unable to make the connection between the analogue and the real object. Some high school and college students in introductorvchemistrv courses experience this same difficulty in connecting analogues with chemistry phenomena (64.One reason for this lack of understading is that science instruction includes the introduction of theoretical constructs such as the kinetic molecular theory before students have become familiar with the macroscopic properties of the world that surrounds them. They memorize the theory and apply it unwittingly, or they extend the theory incorrectly. Oshorne and Cosgrove (9) found that when children in New Zealand were shown a picture of a transparent vessel containing boiling water and were asked a multiplechoice item ahout the nature of the bubbles that formed in the water, 40% of the 725 17-year-old students thought that thev were made of hvdroeen and oxveen rather than water that 14- and 15mofecules. Vos and kercionk (10) f&d vear-old students in a chemistw course in Utrecht had many conceptual errors about m o l e d e s even after instruction. They state: ~
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Several groups, after learning that in hot water the moledes move fester than in cold water, continued to talk about hot and cold molecules as if themolecules werenot only inmotion but also had atemperature of their own. One group, after adiscussion with the teacher, corrected this view by writing that even in hat water the molecules are cold inside. Although the above examples in no way prove that preaentine theoretical constructs too earlv causes children to acqui; misconceptions, it does give cgildren opportunities to create in their own minds explanations that will be intellectually satisfying to them but yet do not correspond to reality. If children were constructing this knowledge based on a broad view of macroscopic observations, there would be less cause for concern. What actually seems to be happening, however, is that the theoretical information is replacing hands-on experiences with concrete obieets--what might be called "nature study". Recommendations for Teachlng Chemistry
Studv Nature
Because adults find intellectual satisfaction in being able to exolain ohvsical ohenomena in terms of the atomic and moleklar {heories does not mean that children also find this intellectuallv satisfying. For children the "what" of science is as interesting as the "why". For a child, watchingtable salt reappear from a solution is an exciting event. There are so many things in nature that are of interest to children that scientists and educators will not run out of exciting things for them to do in erades 1-5. One that thev reallv like is growing alum cryst& even without describing what is occurrine on the oarticle level (11). The hands-on ex~eriences t b 2 children have in the elementary grades witk matter, volume, mass, solutions, chemical changes, and phase and other physical changes on the macroscopic level provide the experimental base for understandine the microscopic view wlien it is presented in terms of the kinetic molecul& theory and the atomic theory at a later time. This approach makes sense not only in terms of the developmen&i level of chil728
Journal of Chemical Education
dren, but it is also sound from the standpoint of teaching ahout the nature of scientific inauirv. Theories arise as explanations of observed Presented in the reverse, the theory is memorized and not properly related to the phenomena from which it was originally derived. Present Concepts in a Varlety of Contexts
If a concept is presented in only one context, children construct extensions of the conceot that are not in accordance with nature. For example, elementary texts frequently state that water freezes at 0 OC and boils at 100 OC. If this is presented as an isolated fact, children gain the mistaken notion that everything freezes and boils at these temperatures. How many other substances have most children seen freeze or boil? After learning about water's phases, can children answer questions like the ones that folfow? D& everything freeze or boil? Can sugar he melted and boiled? Are things cold when they freeze and hot when they boil? Why does butter get soft when it melts, but ice melts all of a sudden? Is the freezine noint lower when vou freeze a laree quantity of water? ~ o ; a ' c a nthe freezing Goint and melting point be the same? Can ice be colder than 0 'C? When given the boiling point and freezing point of another substance, can the phase of the substance be predicted at various temperatures? What is the lowest temperature known? What is the highest temperature known? How hot is the sun? Use Hands-on Experiences
Presenting concepts in a variety of contexts may not he effective in broadening students' conceptual framework on a eiven tooic unless aovrooriate instructional strateeies are ised to teach the concepts. Hands-on activities for the eake of hands-on activities mav do little in enhancine conceot development if the activit; is not properly structured andLif there are no preactivity and postactivity discussions. A wide diversity of activities should be used including reading. Activities should provide some cognitive conflictthings that do not seem "right"-that causes the student to modify his or her thinking. An example of this on the college level occurs when a student reports that the thermometer "has gotten stuck" when collecting temperatures at timed intervals while a substance melts. Seeing the same phenomenon as a demonstration or reading about it in a textbook does not orovoke the same level of conflict or curiositv as doine the same activity oneself. Teach Critical Thinking Skills
Hands-on activities should not only be used to clarify and to extend concepts, but also to teach children to think. Using science process skills (12)that include observing, classifying, inferrine. oredictine. measurine. relation-. u s h -e soaceltime . ships, c&&olling &ables, making hypotheses, interpreting data, defining operationally, using models, and experimenting do this. Unfortunately what has happened to many science curricula at the intermediate level is that thev continually have children focus on the seven basic skilgwhile neglecting the development of the more challenging, integrated skills. Chemistry is an ideal medium for teaching the science process skills while simultaneously teaching chemistry concepts and motivating children to study more chemistry. Present Theories at the Appropriate Time
Children in the intermediate erades have undoubtedlv heard of atoms and molecules and-may be very interested in them. In the intermediate grades children can be presented with explanations of phenomena using particles, but it would he better to set up activities for the puruose of teachof matter raihe; than aspects ing the macroscopic of the kinetic molecular theory. For example, the SClS curriculum contains an experiment in which children boil Freon
in a haggie from the heat of their hand. An ice cuhe placed on top of the puffed-up hag causes the Freon to condense. When some third made children see the dronlets form and return to the bottom of the hag, they describetheir observation as "It's raining!" I t would he much better to determine whether the children think that the "rain" that is forming inside the hae is water from the meltine ice cuhe leakine through the & or they simply call thcprocess of condensing "raining", rather than trying to teach what is happening on the molecular level. Berkheimer (13) found that it was possible to teach children about the particle nature of matter as it is related to phase changes beginning at about the sixth grade level hut not about chemical changes. Considering the findings of Oshorne and Cosgrove (9) cited earlier and the work of Yarroch (14), who found that half of the students whom he interviewed that balanced equations correctly were unable to represent the formulas in terms of atoms and molecules, this is not sur~risine.Even at the middle school level care must be taken n i t to present the
reo on
kinetic molecular theow in lieu of the macrosco~ic hen omenon that forms the bask for the theory. This s t k leaves the auestion ahout the aee level when atomic theorv should he presented. Is high sciool chemistry not soon enough? Literature Clted ~ hinscum i ~ ~ A ~ I ~~ M W tR W P P P~ B - ~ NW York, 19%. 2. Furio Mas,C.J.;Pema, J. H.;Hanis,H. H.J. Chem.Edue. 1987,M, 616. 3. Ch~msfryTho Study ofMotler. Teaeher'a Edition;Allvn and Bamn: Nenton, MA, 1. sciewe ~
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5. Chittenden,E., unpublishedpsper,1988. 6. Dabel. D. L.: Samuel. K. V.J. Res. Sci. Teach. 1986.23.83.
12. he& Science Education &~lemenforySehoal Teachera;AMS Mise.Publiurtion 705,1970. 13. Berkheimer. G.D.; A n d m n , C. W.;Lee. 0.;Blake&~, T. D.Matter and Molecule8. Michigan StateUniu, 1988. . L.J. Re*. Sei. Teach. 1985,22,449. 14. Yarrah, W
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