Forth design of RME: Comparing The Weight of Two Objects by Using a Hanger
Achmad Dhany Fachrudin1 Ummy Salmah2, dan Sitti Busyrah3
International Master Program on Mathematics Education (IMPoME 2012)
email: [email protected], [email protected], [email protected]
I. Introduction easily forgotten by pupils. One of the ways that you can use to make learning maths becomes even more meaningful is by putting mathematic as a part of the student life experience (Wijaya, 2008).
To support the implementation of a meaningful mathematics learning we need an approach that allows the connection between pupils' life experiences with the learning of mathematics, one of these is Indonesia Realistic Mathematics Education (IRME). IRME is an approach adapted from Realistic Mathematics Education (RME) that have been developed in the Netherlands which emphasize on the meaningfulness of a mathematical concepts to pupils itself through the use of context or realistic problem. this encourage researchers to design a learning at the elementary school level using IRME approach.
Ibtidaiyah Negeri 1 Palembang. Here a researcher uses a variety of realistic problems such as weight measurements made by the traders in the market or
store and body’s weight measurement as a starting point for developing the mathematical ideas and concepts. While, the tools media used are various objects that will measure the weight by using hand and cloth’s hanger as a non standard measuring instrument, and home scales as a standard measuring instrument.
Further, the process of the researchers with teachers to design, implement learning on learning in the classroom as well as a retrospective analysis of how researchers will be described in the instructional design below.
II. Designing Instructional
The phases are the preliminary design (analysis of the curriculum and the determination of learning objectives and indicators), continued with the implementation/testing of design (teaching experiment) and do a reflection of learning that had been performed (analysis/retrospective retrospektive analysis) that will be described as follows.
1. Preliminary Design
At this phase, the first steps taken by the researchers was conducting an analysis curriculum to determine the material would be taught, formulating objectives and indicators that would be achieved in learning process, determining the appropriate context to the material, prepare a learning tools such as lesson plan and worksheet to be used in the learning activities in classroom.
In the preparation of the learning tools, researchers and teacher doing the discussion in twice. In the first discussion, the determination of learning material and the context for the material to be taught. While the second was a discussion about worksheet-draft, lesson plan and learning media that had been made by researchers based on the teacher’s advice. Then the researchers did a revision of worksheet and lesson plan based on advice from the teacher.
Based on the results of these discussions, the context of the measurement of weight and objects that exist around the pupils’ lives as the initial step in the formation of the concept of weight measurement. The learning media used by researchers are hangers that are used as a non standard measuring instrument and home scales as a standard measuring instrument. Some of the objects are Staples, like flour, salt, plate, spoon and others as the objects to be measured and compared its weight.
At this phases, a researcher with the teacher learning divide in several activities.
a. Activity 1: introduce students in the problem in daily life that involves the measurement of weight. In this activity, contexts introduced among are the measurement of body’s weight and fruit in the store or market. The purpose of this activity is to guide the pupils about the concept of weight comparison.
b. Activity 2: students compare the weight of two objects using the hands as non standard measuring instrument. The purpose of this activity is to cannot be compared by using hand, that is objects that have a very small weight difference.
d. Activities 4. Students compare the weight of two objects using the home scales as a standard measuring instrument.
Figure 1. Iceberg
2. Teaching Experiment
This learning started with conveying the context that was associated with the measurement of weight. At the beginning of the lesson, the teachers asked the pupils whether they ever buy fruit. Most of the pupils answer “ever”. The teacher then resumed the question. How much fruit you bought in the market? Various answers from pupils appeared at that time. Some said 1 kg, 2 kg, and so on. Then the pupils were given a question again. What does the seller to find out 1 kg, 2 kg and so on? One of the pupils then replied measuring with the scales.
(a) (b) Figure 2. (a) Dividing class into 11,
(b) Pupils read the instruction in their worksheets
The first activity that compares two objects by using a heavy hand. Before this activity begun, the teacher explained the activities they would do. Five pairs of objects which have been provided were put in five different tables. In each table, it provided two pairs of the same objects. So that each table, there are two groups who perform the same activity.
Figure 3. Objects which were weighed by pupils
direct them. After comparing the weight of two objects using the hands, pupils discuss the results of the work they have done.
Figure 4. Pupils were comparing the weight of two objects by using their hands
After completing the first activity, pupils then continued working on the second activities. The second activity was comparing the weight of two objects by using the clothes hanger (hanger). Measured objects remains the same, just different tools used. Previously the two objects which were compared put into a plastic bag. Then the plastic hung on the left and right ends of the hanger. One of the members of the group was asked to hold the hanger handles. The results of the measuring activity that pupils did were written in the worksheet.
Figure 5. Situation when pupils are comparing the weight of two objects by using hanger as the non-standard measurement tool
they were snatched away to choose their favorite color suit hanger and when using hanger to compare the weight of two objects. After finishing the activity, they looked so happy by shouting the word “hore”. It was a sign that they succeed to finish this activity. This activity ended with a discussion on the activities of each group to answer the questions contained in worksheet.
Figure 6. Discussion
The third activity was continued to weigh heavy of objects by using home scale that used to weigh flour or sugar. Because the scales provided to weigh every matter was only one, then in the activities, only a few pupils were asked to do the weighing. For starting point, the teacher gave examples of how to weigh objects. At the beginning of weighing pupils were asked to specify the number/point which the scale shown.
Figure 7. Pupils were weighing objects by using scale
that they measured was. They also snatched away and hand-picked each other with enthusiasm in order to get a chance to weigh objects. Measurement results were written on the whiteboard so that all pupils can see the results.
Figur 8. Pupils were discussing
Figure 9. Pupil was writing the results on whiteboard
After all the objects have been weighed, the teacher invited pupils to compare the same objects which were weighing more heavily based on the results that they have done. Next, they discussed whether the results they got from the first activity when considering using the hands, using the hanger on the second activities as well as with the home scales at the last activity stayed the same or not. As a final activity, pupils were asked to conclude the results of learning today about comparing the weight of two objects.
3. Retrospective Analysis
groceries they saw when accompany their mother to market. They also pay close attention when the teacher gives directions about what they would do with their groups.
Figure 10. Pupils pay attention to teachers’ explanation
In the first activity on the first worksheet, each group works compact. They do not experience severe difficulties when comparing two objects of significant weight difference by using the palm of the hand like salt with cotton, a book with a cork, and 1 kg sugar with flour ½ kg. However, it is not easy for pupils to compare the two objects which have the same weight, namely spoon and cup. Some groups responded heavier glass, and others answered a spoon. There is only one group that answers these two objects are the same weight.
Figure 11. Pupils seemed excited to compare weight of objects by using the palm of hand
obtain accurate results. Teachers also lure pupils how to determine where a heavy object by looking at the position of both ends of the hanger.
Figure 12. Pupils’ activities compare weight of objects using a coat hanger
On the whole of the activities of these two groups, almost all replied that spoons and glasses have the same weight than when they compared with just using the palm of the hand. However, the reason of how they know where the heavier object varies. Some groups argued because that heavier objects because it was bigger, or more content, or with regard to the end of the coat hanger downward.
Figure13. Pupils’ reasons to determine the object that is heavier by using a coat
hanger
The concept of weight measurement using non-standard and standard units should be implemented during 2 meetings. So that learning math on that day should be finished at 11:10 pm continued till 11:30 pm. Teaching and learning process followed by weighing all the objects (books, sugar, flour, cork, salt, cotton, bowls, plates, spoons, glasses) with a balance scale figures covered. This is to facilitate pupils understanding leads to the standard unit of weight i.e. grams, pounds and ounces. Pupils are excited about doing the weighing was guided by the teacher. They calculated the scale of weights and wrote the results on the board. It is not believed by the researchers was a pupils answered weigh sugar is equal 1 kg. Even though teacher do not provide an explanation of this standard unit.
gram. For example, at the time wrote 3 units equal to 30 grams, but when 35 units they still write 35 grams, and some even wrote 305 grams. This is because the second grade pupils have not learned the concept of multiplication and the concept of numbers hundreds of them have not been established. One of his pupils is Gempar, which according to the guardian class is a smart pupils, was able to write all the weight of heavy objects from the unit to a standard unit gram. With activities using objects weighing scales, pupils were able to determine that heavier objects have a number of objects that weigh greater results. At the end of the lesson the teacher directs the pupils to see the results of the weighing of sugar which is 100 units or equal to 1000 grams who has written one of his friends said. Then the teacher shows the 1 kg of sugar listed on the packaging. Thus, the pupils can conclude that 1000 grams equals 1 kg.
Figure 14. Pupils’ answer (weight units and grams)
III. Conclusion
Teaching the concept of weight measurement can be started by the context in which it is known by the pupils as weighing groceries purchased in the shop or in the market. Further indicators comparing the weight of two objects can be done using a coat hanger. Using hangers pupils are able to understand the concept of weight that can lead pupils to gauge and standard units.
really enjoy these activities, because pupils learn while playing. Similarly, they measure the weight of objects by using balance. Although pupils still seemed confused and mistaken when writing unit weight in grams of the standard weight unit, pupils still look enthusiastic when measuring the weight of a variety of objects.
Iceberg learning about how to measure weight that has been done in MIN 1 Palembang as follow:
Figure 15. Iceberg Learning of Measurement Weight Concept
REFERENCE
Wijaya, Ariyadi. 2012. Penidikan Matematika Realistik: Suatu Alternatif
Pendekatan Pembelajaran Matematika. Yogyakarta: Graha Ilmu.
Contoh permasalahan kontekstual untuk pengukuran berat
