report Comparing The Weight of Two Objects by Using a Hanger
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
One of the principles of mathematics education is pupils can truly
understand the concepts being taught. To be able to understand the math
concepts, a knowledge or mathematical concepts must be meaningful for the
pupils. A knowledge will be meaningful for pupils if the learning process
involves realistic problems or are implemented in and by using the context
(Wijaya, 2008). Therefore, in the teaching and learning process we could not
put mathematics as an object that detached from reality which is easily
understood by pupils. It makes learning math becomes less meaningful and
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.
The material selected by the researchers on the development of
instructional design with IRME approach this time is a measurement with a sub
material comparing the weight of two objects with a nonstandard and standard
unit. The learning design will be applied for grade 2 pupils of Madrasah
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.
Based on the results of the first discussion researchers with the teacher
(Tartilah), the material to be taught is measuring the weight. The selected
indicators is comparing the weight of objects with the non standard
measuring unit and standard measuring unit. Learning will take place on once
the meeting or 2 hours of instruction. To support the implementation of the
learning design properly, then the research team with teachers designed the
learning tools such as lesson plan and worksheet to be used in the learning
process that is appropriate with the IRME approach.
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
emphasize to the students that the hand can be used as non standard
measuring tool.
c. Activity 3: students back is comparing two objects by non standard
measuring instrument, but this time by using a hanger. The tool used to
facilitate the understanding to the pupils that there are some things that
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.
This is the design of the iceberg of learning made by researchers and teacher.
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.
The introduction was enough to introduce the material that they would
learn that day. After the activity, the teacher then invited pupils to participate in
the main activities. Main activity consisted of three activities: the first activities
was that compared the weight of two objects using their hands, the second activity
that compared the weight of two objects by using clothing hanger (hanger) as the
non-standard measurement tools, while the third activity which compared the
weight of two objects by using home scale that is usually used for weighing the
sugar or flour. Before doing such activity, the pupils were divided into 11 groups.
Each group consists of 3 people. Each group was given the worksheet.
(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
To compare the first pair of object, each of the two groups were asked to stand on
a table that has placed the objects you want to compare later. For example, the
first and second groups will be measuring in the first table. Group 3 and 4 would
be measuring objects in the second table, and so on. To organize all groups,
teachers provided the instruction to switch and compare the following pairs of
objects that are located in the other table. Teachers provide the instruction by
shouting the words “move” while clapping. All groups done the activities
enthusiastically. The results of the activities were written in worksheet which has
been distributed to each group. Although there were some pupils who seem
snatched away to do the activity, the activity still took place well. If there are
members of the group who fight each other or snatched away, the teacher tries to
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
In the second activity, teachers provided the instruction like at the first activity to
organize pupils during a move to a table where other objects they will measure
were. Pupils looked very enthusiastic about doing this activity. It looked when
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
After that, pupils were guided to determine how many grams of weighing results.
For example when considering the weight of the book, the home scale of which is
appointed by the needle of the scales is 35, means the weight of book is 350
grams. It was similar to other objects. Pupils seemed enthusiastic in this activity.
Sometimes the debate while reading the scale appeared. Some pupils looked
confused and made mistakes in determining how the weight in gram of objects
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
In general, the implementation of the learning process is going well and smoothly.
Pupils enthusiastically attend any activities provided by the teacher. Each group
showed good cooperation and compact in doing any given activity. At the
beginning of learning, when the teacher asked the activity or activities that pupils
experienced related to weight measurement. Some pupils responded weight
measurement activities such as body weight or weighing process vegetables and
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
Before starting the second activity, the entire group back into place to
listen to the guidance teacher about the activities that will be done is compare the
weight of two objects using a coat hanger. When asked how to use a coat hanger
to compare two objects, some pupils look of confusion and doubt. But one
member of the group 3 forward confidently demonstrates in front of his friends.
Teachers then explain a coat hanger to hold true for the process of weighing later
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
In this activity pupils were able to determine that heavier objects by
looking at the position of the object at the end of the hook downward. However,
some groups are still experiencing problems when pouring their argument on
Pupils Worksheet. The interesting thing, which some groups are wrong when
weighing two objects of the same weight, namely glass and spoon error caused
members of the group in charge of holding the coat hanger. It is a matter of
internal discussion group. Because there are some members who see that the
position of the end of a coat hanger when weighing the two objects are equal, but
the other group members refute his statement. These different opinions,
accompanied by their researchers consulted, pupils concluded then write the
results on worksheet. The situation reveals the principles of realistic mathematics
learning that interaction between one pupil with other pupils. In addition, it can
train pupils in critical thinking skills.
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.
This activity is directed pupils find themselves how much weight each of
the objects that have been weighed (using a coat hanger) in units of grams by
using scales. With the teacher's explanation that the scale unit is equal to 10
grams, there are still many pupils who have not been able to write unit weight of a
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.
In general, learning about measuring weight using a coat hanger has been
run well. Indicators of learning can be done well even though there are obstacles
and problems that arise during the learning process takes place. Pupils seem
enthusiastic and works very compact in their respective groups when comparing
the weight of items given either by using the palm of the hand or by using a coat
hanger. It is also due to the rolling method when weighing these objects. Pupils
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:
Formal abstrak: mengukur berat benda dengan menggunakan
timbangan dan satuan baku gram
Penggunaan tangan sebagai model of dan gantungan baju
sebagai model for untuk membandingkan berat dua benda
Contoh permasalahan kontekstual
untuk pengukuran berat
Figure 15. Iceberg Learning of Measurement Weight Concept
REFERENCE
Wijaya, Ariyadi. 2012. Penidikan Matematika Realistik: Suatu Alternatif
Pendekatan Pembelajaran Matematika . Yogyakarta: Graha Ilmu.
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
One of the principles of mathematics education is pupils can truly
understand the concepts being taught. To be able to understand the math
concepts, a knowledge or mathematical concepts must be meaningful for the
pupils. A knowledge will be meaningful for pupils if the learning process
involves realistic problems or are implemented in and by using the context
(Wijaya, 2008). Therefore, in the teaching and learning process we could not
put mathematics as an object that detached from reality which is easily
understood by pupils. It makes learning math becomes less meaningful and
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.
The material selected by the researchers on the development of
instructional design with IRME approach this time is a measurement with a sub
material comparing the weight of two objects with a nonstandard and standard
unit. The learning design will be applied for grade 2 pupils of Madrasah
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.
Based on the results of the first discussion researchers with the teacher
(Tartilah), the material to be taught is measuring the weight. The selected
indicators is comparing the weight of objects with the non standard
measuring unit and standard measuring unit. Learning will take place on once
the meeting or 2 hours of instruction. To support the implementation of the
learning design properly, then the research team with teachers designed the
learning tools such as lesson plan and worksheet to be used in the learning
process that is appropriate with the IRME approach.
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
emphasize to the students that the hand can be used as non standard
measuring tool.
c. Activity 3: students back is comparing two objects by non standard
measuring instrument, but this time by using a hanger. The tool used to
facilitate the understanding to the pupils that there are some things that
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.
This is the design of the iceberg of learning made by researchers and teacher.
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.
The introduction was enough to introduce the material that they would
learn that day. After the activity, the teacher then invited pupils to participate in
the main activities. Main activity consisted of three activities: the first activities
was that compared the weight of two objects using their hands, the second activity
that compared the weight of two objects by using clothing hanger (hanger) as the
non-standard measurement tools, while the third activity which compared the
weight of two objects by using home scale that is usually used for weighing the
sugar or flour. Before doing such activity, the pupils were divided into 11 groups.
Each group consists of 3 people. Each group was given the worksheet.
(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
To compare the first pair of object, each of the two groups were asked to stand on
a table that has placed the objects you want to compare later. For example, the
first and second groups will be measuring in the first table. Group 3 and 4 would
be measuring objects in the second table, and so on. To organize all groups,
teachers provided the instruction to switch and compare the following pairs of
objects that are located in the other table. Teachers provide the instruction by
shouting the words “move” while clapping. All groups done the activities
enthusiastically. The results of the activities were written in worksheet which has
been distributed to each group. Although there were some pupils who seem
snatched away to do the activity, the activity still took place well. If there are
members of the group who fight each other or snatched away, the teacher tries to
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
In the second activity, teachers provided the instruction like at the first activity to
organize pupils during a move to a table where other objects they will measure
were. Pupils looked very enthusiastic about doing this activity. It looked when
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
After that, pupils were guided to determine how many grams of weighing results.
For example when considering the weight of the book, the home scale of which is
appointed by the needle of the scales is 35, means the weight of book is 350
grams. It was similar to other objects. Pupils seemed enthusiastic in this activity.
Sometimes the debate while reading the scale appeared. Some pupils looked
confused and made mistakes in determining how the weight in gram of objects
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
In general, the implementation of the learning process is going well and smoothly.
Pupils enthusiastically attend any activities provided by the teacher. Each group
showed good cooperation and compact in doing any given activity. At the
beginning of learning, when the teacher asked the activity or activities that pupils
experienced related to weight measurement. Some pupils responded weight
measurement activities such as body weight or weighing process vegetables and
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
Before starting the second activity, the entire group back into place to
listen to the guidance teacher about the activities that will be done is compare the
weight of two objects using a coat hanger. When asked how to use a coat hanger
to compare two objects, some pupils look of confusion and doubt. But one
member of the group 3 forward confidently demonstrates in front of his friends.
Teachers then explain a coat hanger to hold true for the process of weighing later
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
In this activity pupils were able to determine that heavier objects by
looking at the position of the object at the end of the hook downward. However,
some groups are still experiencing problems when pouring their argument on
Pupils Worksheet. The interesting thing, which some groups are wrong when
weighing two objects of the same weight, namely glass and spoon error caused
members of the group in charge of holding the coat hanger. It is a matter of
internal discussion group. Because there are some members who see that the
position of the end of a coat hanger when weighing the two objects are equal, but
the other group members refute his statement. These different opinions,
accompanied by their researchers consulted, pupils concluded then write the
results on worksheet. The situation reveals the principles of realistic mathematics
learning that interaction between one pupil with other pupils. In addition, it can
train pupils in critical thinking skills.
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.
This activity is directed pupils find themselves how much weight each of
the objects that have been weighed (using a coat hanger) in units of grams by
using scales. With the teacher's explanation that the scale unit is equal to 10
grams, there are still many pupils who have not been able to write unit weight of a
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.
In general, learning about measuring weight using a coat hanger has been
run well. Indicators of learning can be done well even though there are obstacles
and problems that arise during the learning process takes place. Pupils seem
enthusiastic and works very compact in their respective groups when comparing
the weight of items given either by using the palm of the hand or by using a coat
hanger. It is also due to the rolling method when weighing these objects. Pupils
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:
Formal abstrak: mengukur berat benda dengan menggunakan
timbangan dan satuan baku gram
Penggunaan tangan sebagai model of dan gantungan baju
sebagai model for untuk membandingkan berat dua benda
Contoh permasalahan kontekstual
untuk pengukuran berat
Figure 15. Iceberg Learning of Measurement Weight Concept
REFERENCE
Wijaya, Ariyadi. 2012. Penidikan Matematika Realistik: Suatu Alternatif
Pendekatan Pembelajaran Matematika . Yogyakarta: Graha Ilmu.