Photosynthesis: Teaching a Complex Science Concept to Juvenile Delinquents *

DAVID W. TEST AND WILLIAM L. HEWARD The Ohio State University, Columbus, Ohio 43210

lntroduct ion

Behavioral techniques have proven effective in increasing student performance in a wide range of academic skill areas, including mathematics (McCarty et al., 1977; Van Houten & Thompson, 1976), spelling (Ballard & Glynn, 1975; Fawcett & Fletcher, 1977), writing (Neef et al., 1977; Rapport & Bostow, 1976), and reading comprehension (Knapczyk & Livingston, 1973, 1974; Lahey et al., 1973). However, research on in- struction of science concepts, a subject area included in most school curriculum, is no- ticeably lacking in the behavior analysis literature.

Teaching science concepts to special populations is a demanding task requiring a systematic approach and innovative activities (Esler et al., 1977; Schery, 1975). One group of learners that presents special problems for academic instruction is juvenile de- linquents (Sabatino & Mauser, 1978a, 1978b). Delinquent youths frequently display low academic achievement (Jerse & Fakouri, 1978). While applied behavior analysis has proven effective with juvenile delinquents, most of the studies have reported modi- fication of social behaviors (e.g., Liberman et a]., 1975; Phillips et al., 1971). Some studies with juvenile delinquents have focused on increasing academic behavior ( e g , Tyler & Brown, 1968); however, none could be found that investigated knowledge of a scientific concept as the dependent variable.

The Visual Response System (VRS) was created by Wyman to raise the level of activity and interaction in classrooms for the deaf (Heward, 1978a; Wyman, 1968, 1969). The VRS is a classroom where each student’s desk has a built-in or adjacent overhead pro- jector. Students respond by writing, pointing, matching, placing objects, etc., on the stage of the overhead projector. The teacher also has an overhead projector and possibly a 35 mm slide projector and filmstrip projector for presenting visual stimuli to the students. The most common arrangement for the VRS is to align the student overhead projectors in a horseshoe-shaped configuration with the teacher’s projector at the open end. For a more complete description of the VRS see Heward (1978b).

* This research was supported by a grant from the Bureau of Education for the Handicapped (No. (3007703334) to The Ohio State University Research Foundation. The authors are indebted to Dr. Christ L. George, Superintendent of Education, Ohio Youth Commission, Mr. Ron Stewart, Principal, Buckeye Youth Center, and Mr. Jeffrey Alexander and Ms. Janine Bourdo, science teachers, Buckeye Youth Center, for their support of this research. Reprints may be obtained from William L. Heward, Faculty for Exceptional Children, The Ohio State University, 356 Arps Hall, 1945 North High Street, Columbus, Ohio 43210.

Science Education 64 (2): 129-139 (1980) Q 1980 John Wiley & Sons, Inc. 0036-8326/80/0064-0l29$01 .OO

130 TEST AND HEWARD

The two most powerful instructional features of the VRS are (1) active student response is generated, all students respond to all questions or problems rather than taking turns, and (2) all student responses can be directly observed allowing the teacher to provide virtually immediate feedback to each student.

A V R S was used to teach a standard chemistry curriculum to 13 students, aged 15- 17, at a high school for hearing students (Barrette, 1971). The completion of workbook as- signments was reinforced immediately with points that counted toward the course grade. I n addition, the V R S has been shown to be an effective technology for teaching sentence writing skills to deaf children (Eachus, 1971; Heward & Eachus, in press) and compu- tation of math fractions (Shadding, 1979), completion of employment applications (Joynes et al., 1978), and self-management skills (Marshall, 1979) to institutionalized juvenile delinquents.

Method

Subjects Seven male students, ages 13-18, enrolled in a science class at a residential correctional

facility for juvenile offenders served as subjects. The students were selected based on their performance on a pretest covering photosynthesis (see Procedure) given to determine what students could benefit most from the program. Prior to coming to the correctional facility the students were in grades 9-1 1 in public schools. The students’ reading com- prehension, as measured by the Gates-MacGinitie Reading Tests (Gates & MacGinitie, 1965) upon admission to the facility, ranged in grade level from 5.3-12.6 with a mean of 7.3. Their math ability, as measured by the California Achievement Test (Tiegs & Clark, 1970), ranged in grade level from 4.0-7.6 with a mean of 6.3.

Setting

The experiment was conducted in an eight-student VRS located in the high school at the correctional facility (see Fig. 1). Student overhead projectors were built into the desks and the projected images were focused on anti-keystoned screens constructed of 3/4 in. flakeboard covered with egg-shell white Formica. This provided a durable and washable projection surface.

Each student desk also contained a feedback unit that consists of a red light, a green light, a teacher call button, and an electronically operated counter that can be advanced with switches located at the teacher’s desk. Also at the teacher’s desk were individual and master switches to control all of the overhead projectors. The teacher’s desk also contains a sound system consisting of a cassette tape deck and intercom. The sound system was used to provide corrective feedback and verbal reinforcement to students.

Turger Behavior The photosynthesis program was developed in conjunction with a science teacher at

the correctional facility. The concept of photosynthesis was divided into four major parts, requiring students to: ( 1 ) write the three major parts of a green plant and state two functions of each part; (2) write the chemical symbols for the atoms and molecules in the photosynthesis equation, and, given the symbol for a compound, calculate and write

TEACHING COMPLEX SCIENCE CONCEPTS 131

s ' O'h' I

I X l l I I I I I ' I - L II A

1 anti-keystoned w d I Figure 1. Floor plan of VRS-Buckeye Youth Center.

the number of molecules and atoms in the compound; (3) write the photosynthesis cycle; and (4) write a definition of photosynthesis that includes seven distinct components. The dependent variable throughout the study was the number of answers correct in each part as measured by recording students' responses on a written paper-and-pencil test requiring a total of 3 1 responses (see Table I). The test was administered seven times throughout the study, once as the pretest, once after each part was taught, and as the three and six week follow-up test.

M a teria 1s * In addition to the master test, the teacher and students used the following materials

during certain instructional sessions. Teacher Overhead Transparencies. Teacher Overhead Transparencies (TOTs) were

used to present new concepts to the students. Information was presented using overlays, masking, and progressive disclosure. All TOTs required the students to respond in some way to the information presented by the transparency.

Student Response Slides. Student Response Slides (SRSs) are 3 in. X 3 in. acetate slides that contain single words or phrases. Students were required to place on their overhead projectors response slides containing the correct answers to questions or problems pre- sented by the TOTs. SRSs were used to identify the three parts of a green plant, two functions of each part, and the photosynthesis cycle.

* Copies of instructional materials used in this program may be obtained by writing the authors at the address given on page 129.

132 TEST AND HEWARD

TABLE I Target Behaviors Included in Photosynthesis Unit

I . Name the three major p a r t s of a green p l a n t and l i s t two func t i ons

o f each p a r t . (9 p o i n t s )

1. leaves

a. absorb gasses

b. manufacture food f o r the p l a n t

2 . stem a. supports the p l a n t

b. conducts l i q u i d s up and down

3 . _Roots

a. absorb water

b. absorb n u t r i e n t s

I t . Wr i te the chemical symbols f o r the f o l l o w i n g chemical names. (9 po in ts )

1. Carbon D iox ide - 2. Water ==

3 . Oxygen - 02 - 4 Hydrogen - H

5. Carbon =c Answer the Fol lowing: 8 ~ 2 ~ 0 4

6. 8 molecules

7. 16 atoms o f hydrogen

8. 8 atoms s u l f u r ( s )

9. 32 atoms oxygen

I l l . Complete the photosynthesis cyc le by f i l l i n g i n the blanks (6 p o i n t s )

1 . Man exhales carbon d iox ide .

2. P lan ts take i n carbon d i o x i d e and water.

3 . Plants make sugar ( food1 and m. 4. Man breathes m.

I V . Wr i te the d e f i n i t i o n o f photosynthesis. ( 7 p o i n t s )

Photosynthesis i s the process by which green p l a n t s take i n

carbon d iox ide and yBLcT. and us ing energy from the sun.

make food (sugar) and m.

Student Response Transparencies. Student Response Transparencies (SRTs) were divided equally into six numbered sections. Students either wrote answers or placed re- sponse slides in the numbered sections of the response transparency as directed by the teacher. SRTs resulted in each student organizing his/her responses the same way on the overhead projector, making it easy for the teacher to quickly scan the projected re- sponses and provide feedback as appropriate.

TEACHING COMPLEX SCIENCE CONCEPTS 133

Atom Transparencies. Atom Transparencies (ATs) were 1 in. circles of transparent acetate with the letter H (hydrogen), C (carbon), or 0 (oxygen) written on them.

Experimental Design A multiple-baseline-across-behaviors design (Baer et al., 1968) was used to evaluate

the effectiveness of the instructional program. In a multiple-baseline design, data are collected on two or more dependent variables simultaneously. An intervention is then performed on one of the dependent variables, and changes in that behavior are contrasted with the steady states of the other dependent variables. Another behavior is then selected as the target of the intervention and its performance is measured, When each dependent variable changes maximally at the point of intervention, one may conclude that the in- tervention is effective in controlling the behaviors under study. For a more detailed de- scription of -the multiple-baseline design, see Sidman (1960).

Each of the four parts of photosynthesis was taught in succession (see Table I). Each time the instructional program was completed for a set of items, the students were ad- ministered the test. Data from the students’ performance each time they completed the test were used in the multiple-baseline analysis.

Procedure Pretest. Students were given 20 minutes to complete the master test in a regular

classroom setting. Subsequent administrations of the master test were given in the VRS immediately following the completion of each part. Except for the followup tests, students received no feedback on their performance on the master test.

Teaching procedure. Although the specific teaching procedure was different for each of the four parts, the general procedure followed a stimulus-student response-feedback model. Approximately 90% accuracy was required of each student during each step before proceeding to the next step. During some steps all student overhead projectors were “on” while students responded, and students were allowed to look at each others’ responses. A total of five daily 40 minute instructional sessions was required to complete instruction on all four parts. Each part required approximately one period to teach, but the admin- istration of the test after each part was completed caused the study to last an extra day. Table I 1 summarizes the teaching procedure used for Part I-Green Plants: Their Parts and Functions.

Points earned by each student were exchanged for cigarettes or lottery tickets (20 points = 1 ticket or 1 cigarette). Lottery tickets were drawn at the end of the photosynthesis unit, until three different winners had been selected. Winners could choose either a soft drink or a rock ’n roll poster.

Three-week and six-week followup. Three weeks (13 school days) after the photo- synthesis unit was completed, the students were asked to complete the master test. Feedback, in the form of returning the graded test, was given to each student within one week following this test. Six weeks after the photosynthesis unit was completed the stu- dents were again asked to complete the master test. The six-week followup test was conducted with only three students; the remaining four students were no longer at the correctional facility.

TAB

LE I

I T

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r P

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The

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(OW

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10

wri

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. A

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ap

pro

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ch

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w p

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D z 0 I

rn 5 n 0

TEACHING COMPLEX SCIENCE CONCEPTS 135

BASELINE AFTER VRS INSTRUCTION FOLLOW-UPS

ln I- n W u 2 s

I I -

a

b-L

0 9 ; ; ? ! I I 1 PRETLST I 2 3 4 S W L K 6WLEK

PROBES

Figure 2. Average number of questions answered correctly by seven students before and after instruc- tion.

Interobserver reliability. A second, independent observer graded all of the master tests completed by the students throughout the study. Reliability was computed by dividing the number of questions on which both graders agreed by the total number of questions attempted and multiplying by 100. Reliability on the pretest was 96.3%. Reliability was 97, 99.5, 98.5, and 99% on the tests given after instruction on each of the four parts. Reliability was 98.6 and 100% on the three-week and the six-week followup tests, re- spectively.

Results

Figure 2 shows the average number of questions completed correctly by the seven students on the master test across the four parts. Mean performance of the seven students is presented because it is representative of each student's behavior, except for student 1 who answered six of nine questions correctly on part 11 on the pretest, and remained at this level throughout the study. Student 1 was absent the day part 11 was taught. Students averaged 6.3 (range 0-1 1) questions correct on the pretest. 29.5 (range 24-31) correct on the probe following instruction on all four parts, 25.4 (range 13-31) correct

136 TEST AND HEWARD

on the three-week followup, and 27.3 (range 21-31) correct on the six-week follow- UP.

Discussion

Results of this study show that the instructional program was effective in teaching juvenile offenders basic principles of photosynthesis. After instruction on all four parts, two students answered all 3 1 questions correctly, three students completed 30 questions correctly, one student completed 28 questions correctly, and student 1 answered 24 items correctly. One factor that may have worked to keep student 1’s score low is the fact that he did not receive instruction, due to absence, on the second set of items-atoms and molecules. Although his pretest score was six of nine questions correct, these answers were on writing the symbols for different chemicals. Student 1 was not able to calculate the number of atoms and molecules in a compound on the pretest. Student 1’s perfor- mance on the other three parts increased after instruction. The fact that student 1’s performance on the second part did not increase (since he was absent during training), lends support to the effectivenesswf the instructional package.

The technology provided by the VRS allowed the teacher to incorporate at least four positive features into the program. First, high rates of student response were maintained during the program. Schery (1975) has pointed out the importance of active student participation in teaching science to low-achieving students. Hall et al. (1 977) have noted that a major difference between inner-city children who are academically behind their suburban peers is that inner-city classrooms, as a rule, provide students with very little opportunity to actively engage in the skills they are supposed to learn. In several studies, Hall and his colleagues found that simply increasing a student’s opportunity to respond often resulted in academic gains. They write, “we . . . should . . . find systems which will allow pupils to increase their responding which will not be punishing to the teacher because of the heavy workload they might impose” (1977, p. 22).

In this study, the average number of responses per student during a 40 minute period was 55, 25, 18, and 25 for the four parts of the photosynthesis unit. (Differences in the number of responses made by each student across the four parts of the program are a function of the different content and procedures used in each of the parts.) This rate of student response was accomplished in a small group setting, meaning that a total of 385 individual student responses were emitted and received feedback during the session on green plants. Use of SRSs in certain parts of the program was partly responsible for the high student response rate. Instead of writing out answers, a student only had to place a response slide on the stage of his overhead projector.

The second positive feature of the program was that each student response received feedback almost immediately. The teacher only had to scan the projected responses to get visual access to each student’s work. Use of the SRTs meant that when students emitted responses to a series of questions, each student arranged his responses in the same format. This enabled the teacher to locate quickly a student’s response to each particular question. To reinforce correct responses, the teacher simply had to move a toggle switch on the teacher’s console, advancing the student’s counter. After all students had re-

TEACHING COMPLEX SCIENCE CONCEPTS 137

sponded, the teacher projected the correct response, which provided remedial feedback to students who had not responded correctly.

Third, the VRS enabled a variety of student responses to be incorporated into the program. Esler et al. ( 1977) recommended employing manipulative materials when teaching science concepts to exceptional students. In the part on atoms and molecules, each student constructed directly on the stage of his overhead projector molecules from individual atom transparencies. This exercise helped the students to experience a concrete dimension of a concept that previously had been entirely abstract, to determine the composition of the molecule in photosynthesis, and to help conceptualize the chemical equation of photosynthesis.

Finally, because the students could see each others’ responses when the overhead projectors were “on,” they were able to use their classmates’ correct responses as models. This student-student interaction made possible by the VRS may have resulted in feedback directed toward one student serving as a functional consequence for other students. On numerous occasions a student, who had committed an error similar to one made by a peer, would self-correct his response after he had seen the teacher remediate his peer’s work.

Results of the two followup tests show the students not only maintained the knowledge they had acquired about photosynthesis, but that generalization across academic settings had occurred. Facts demonstrated in the VRS were recalled by students on followup probes presented in their regular classroom (see Fig. 2).

Students were administered a questionnaire about the program after the three-week followup test. All seven students reacted very positively to the VRS in general and to the photosynthesis unit in particular. Students stated that they enjoyed being “right” so often (all students responded with over 95% accuracy during the instructional sessions) and one student said that the VRS made it possible for students who did not know an answer to learn from him, if his response was correct, and vice versa.

In summary, the program enabled the students to learn basic facts of photosynthesis in five 40 minute sessions. Science teachers at the school where this research was con- ducted felt it would take at least two weeks to teach the same concepts in the regular classroom, and they doubted students would do as well. Results of the present study suggest that the VRS, which enables all students to respond actively in a variety of ways, is an effective environment in which to teach science concepts.

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Received 16 April 1979 Revised 28 June 1979 Accepted for publication 26 July 1979