The effects of Swedish Knife Model on students’ understanding of the digestive system

Subjects

The subjects involved in this study were 7th grade students at an elementary school in Gumushane. The teaching model under investigation was applied in two classes, a total of 40 students. The sample was informed of the research subject in a traditional lecture before the study.

Data Collection

The Digestion System Test (DST) was used in this study and consisted of 7 open-ended questions. The targets of the questions were given in Table 1. The purpose of this test was to evaluate the effectiveness of Swedish Knife Model, by comparing the results of the tests which was given before and after the instruction. The validity and reliability of the DST was established by giving the questions to three science teachers and by conducting interviews with those students who sat the DST. They all agree that the questions were readable, clear and appropriate. The test was administered twice: once on the first day of the study (pre-test) and once in the fifth week of the study, after application of the worksheet had been completed (post-test). The administration of the test was as follows: the papers were distributed to the students and each student wrote his/her answer on the test paper. The total time taken to complete the test was about 20 minutes.

Upon completion of the study, semi-structure interviews were conducted with 10 students. All the participants were individually interviewed. Each interview lasted about 15 min. The students were asked to asses the teaching process.

**Table 1.** Targets of the DST’ questions
*Items*	*Targets*
1	Explanation of digestion Digestive tract Mechanical digestion Chemical digestion Function of liver Function of large intestine Analogies for digestive organs and structures
2
3
4
5
6
7

Analysis of the Data

Different criteria are used in the literature, in terms of open-ended questions. In this study, a simple categorization was used, based on students’ answers, and each of these categories was identified as different learning levels (given in Table 2). Students’ answers were graded by each of the authors and discussed, until it was agreed which category they would go into.

**Table 2.** Criteria used in the evaluation of the students’ answers
*Levels*	*Categories*	*Shortenings*
A	Correct choice, scientifically correct and full explanations	CE PC CW W UE/NE
B	Partially correct explanations
C	Both correct choice and wrong explanations
D	Wrong explanations
E	Unrelated/No explanations

The data from the interviews were analyzed qualitatively, after completing the data collection; records were transcribed verbatim as soon as possible. Students’ answers were categorized according to agreement and disagreement.

Teaching Design

The overall study was completed in 6 hours and the prior knowledge of the students was determined by using DCT. After students had grouped and delivered the worksheets (10 mins), the treatment was started and five activities were completed in 110 minutes:

First Activity (10 mins): The lesson began with a class discussion based on the dialogue between Sylvester and Tweety. The aim of this activity was to ascertain the views of the students in terms of digestion in general.

Second Activity (20 mins): A general description of digestion was given by the teacher and the students were keen to solve the puzzle, in accordance with the directions given in the worksheet. Five boxes are present on the puzzle; each of them represents a structure of digestive system respectively. Students will find the correct poem for each box firstly and then they will find the drawing and analogy of this structure. After completion of this part, all of the answers of the groups were discussed and the correct answers were repeated by the teacher. The main aim of this part was to teach the functions of the organs and their structures. Following is an example from this activity.

Poem for box 1: I am going to stomach from the pharynx           Correct answer: esophagus
                           This is a thin, long and muscular path
                           There is no digestion in this place

Correct analogy: Correct drawing:

Third Activity (20 mins): Students were given a structured grid and they were asked to write the answers. After completion of this activity, the answers of the groups were discussed in the class. This activity aimed to examine students’ understanding of the topic.

large intestine	small intestine	mouth
esophagus	teeth	stomach
liver	anus	salivary

In which organs digestion occurs?
In which organs mechanical digestion occurs?
In which organs chemical digestion occurs?
Which of them helps digestion?

Fourth Activity (40 mins): ‘Fill the blanks in the story’ activity aimed to assess what the students had learned. These activities also provide an opportunity to strengthen students’ knowledge.

I am an apple, my digestion story started in the ……. Teethes disassembled me smaller parts and I was digested ……………. by saliva. Means that I digested both …………….. and chemically an moved through the esophagus by the aid of muscular contraction and I conducted to the stomach. There was no digestion in the esophagus. My name was bolus now. There are strong ………….. in the stomach. They digested me mechanically and also …….. digested me chemically. Now I was a chime. Stomach propelled me into the small intestine. There was a chemical digestion in the small intestine. After completion of digestion, its walls absorbed me. I changed very much, now I could pass into ……….. My waste products passed into the…………... and there was no ……….in it. As I was passing through the large intestine, …………..was absorbed and the left was eliminated through the rectum.

blood, large intestine, secretion, water, digestion, mechanically muscles, chemical digestion, mouth.

Fifth Activity (20 mins): This is a cut-and-stick activity. The organs of the digestive system were drawn on the paper separately. The students cut them and stick on the paper to form digestive tract. The purpose of this activity was to teach the digestive tract and correct place of the digestive organs.