We will study about transportation system on plant. For introduction you should know about main parts of plant first. We will commence with root as the bottomest part of plant, after that move to stem, leaf, flower, fruit and seed. Each of part have their own unique structure and functions.
- Melchisedek Subur -
Tuesday, August 18, 2009
Grade 7 (Experiment Report)
After the completion of experiment about growing plant, it time for you to make complete report about it. Please make the report accordingly with my instructions. Don't forget you should compare 3 seeds (i.e : red bean, corn and mung bean). What's different between the; its growth, its size and structure etc. You can accompany the report with drawing of plants (complete with its major organ parts).
- Melchisedek Subur -
- Melchisedek Subur -
Thursday, August 13, 2009
Grade 8
We already passed introduction about plant. That's mean all of you should know and understand clearly what's all about plant. its function for all living things, its importance usefulness for human kind. We will study plant's part and its function, we will go deeper to understand about all of mechanism inside plants.
- Melchisedek Subur -
- Melchisedek Subur -
Grade 9 (electrostatic)
We have conducted some simple experiments(3 experiments) on electrostatic. Right now, you should understand clearly what electrostatic mean; its characteristics and its difference with electric current. Sure, you should understand basic concept likes : atom. charge, electrical charge etc. Please do remember to submit its experiment's report the soonest.
- Melchisedek Subur-
- Melchisedek Subur-
Grade 7 (plant)
Please do remember to take care of your plants everyday. Observe and take a note what's happen with the seeds. If necessary please draw a picture to make it more easy to understand. Each group should submit its experiment's report one week after the seed have been planted. With this experiment you will familiar with stages of growth of plant, plant's structure and its parts as well.
- Melchisedek Subur -
- Melchisedek Subur -
Wednesday, August 5, 2009
All Grade - National Geographic
Dear all,
I recommend National Geographic as your best source for science stuffs. You can find there National Geographic magazine, Adventure Magazine, Travel magazine, books, video etc. You can visit its official website at www.nationalgeographic.com.
Grade 9
All of student should understand the basic concept of photosynthesis. Photosynthesis which mainly occured at green plant act like food manufacturer for all living things. Photosynthesis is chemical reaction which combine carbon dioxide from the air, water from the ground and using energy from sunshine become simple sugar : glucose, carbohydrate and starch. We will go deeper into its process step by step.
Grade 8
We already at the first step to understand its plant's structure and function. We realized one thing how vital role of green plant for all living things. Green plant not solely produced food i.e simple sugar likes carbohydrate but also its byproduct : oxygen which needed badly for living organism. Without green plant definitely human existence will desist.
Tuesday, August 4, 2009
Grade 9
After we finished flowering plant's topic, every one of you should understand clearly what's all about plants. Before we go deeper into photosynthesis, we have to grasp basic concept of it. Please study hard because we don't have so much time to covered all of topis in details.
Grade 7
Introduction about what plant is already finishedl including flowering plant. Everyone of you should understand about structure of plants and its major organ parts. Please do remember, next week we will conduct practical work : doing some farmer's work. You will apply scientific method to solve problems.
Thursday, July 30, 2009
Grade 7, 8 and 9
Dear all,
After first introduction about what science really is, we will go deeper into each subject i.e Physics, Chemistry and Biology. We already splitted the class into several groups. Sure we hope you can work together as a team, you can help each other.
-Melchisedek Subur-
After first introduction about what science really is, we will go deeper into each subject i.e Physics, Chemistry and Biology. We already splitted the class into several groups. Sure we hope you can work together as a team, you can help each other.
-Melchisedek Subur-
Wednesday, July 29, 2009
7A - Chemistry
Thursday, 30 - 7-2009
Today y 7A start to learn the first Chapter in chemistry..The learn about States of Matter...They already learn from the demonstration given...about 3 states of Matter, solids, liquids and gases..they know also about properties of each states. They know also why the properties are like that..
They have only 1 periods, so this chapter not finished yet....
-ayu-
Today y 7A start to learn the first Chapter in chemistry..The learn about States of Matter...They already learn from the demonstration given...about 3 states of Matter, solids, liquids and gases..they know also about properties of each states. They know also why the properties are like that..
They have only 1 periods, so this chapter not finished yet....
-ayu-
Notice for all students
Dear all,
First, please do remember that we are in international school. That's mean english become our mandatory language. Even all of subjects will be conveyed in english (except bahasa Indonesia). You should use english at all times, even when you talk to your friends. If you can not do that definitely you will get very serious problem : you can not understand even simple topics. So, you have to speak, to write even during you sleep, you dream. If you realize that your english is not good enough then you should improve it in no time. There are so many ways you can do : attend english course, reading a lot, watching movies etc. If you can afford, please buy dictionary for your own good (electronic dictionary much more conveniences than books).
Second, we do realize that we have so many topics to be covered but we don't have any much time. So, please you should study more harder and harder. It would be a good habit if you read and study the topics before you go to the school. If you get any difficulties about the subject please contact and discuss with teacher or your class guardian. It become your personal responsibilities to succeed. You can not keep silent you should do something about it. Become lazy is not an option.
Finally, we do hope we can work together to achieve goals. Have a nice day. God bless you all !!!
First, please do remember that we are in international school. That's mean english become our mandatory language. Even all of subjects will be conveyed in english (except bahasa Indonesia). You should use english at all times, even when you talk to your friends. If you can not do that definitely you will get very serious problem : you can not understand even simple topics. So, you have to speak, to write even during you sleep, you dream. If you realize that your english is not good enough then you should improve it in no time. There are so many ways you can do : attend english course, reading a lot, watching movies etc. If you can afford, please buy dictionary for your own good (electronic dictionary much more conveniences than books).
Second, we do realize that we have so many topics to be covered but we don't have any much time. So, please you should study more harder and harder. It would be a good habit if you read and study the topics before you go to the school. If you get any difficulties about the subject please contact and discuss with teacher or your class guardian. It become your personal responsibilities to succeed. You can not keep silent you should do something about it. Become lazy is not an option.
Finally, we do hope we can work together to achieve goals. Have a nice day. God bless you all !!!
wednesday, 7B
29-07-2009
Today their time to get chemistry, but they have only 1 period..So the lesson started with the introduction to rules and habits. We will continue next week for starting the lesson about chemistry.
-ayu-
Today their time to get chemistry, but they have only 1 period..So the lesson started with the introduction to rules and habits. We will continue next week for starting the lesson about chemistry.
-ayu-
wednesday, y 7A
29-07-2009
For y 7A they started the lesson with introduction to rules in science....After that we continue to start learning the first chapter about measurement and properties of matter. In this periods they learn about measurement unit for mass, length and time. They learn also about International Standard in Measurement Unit. We showed samples of instruments to measure mass, time and length.
-ayu-
For y 7A they started the lesson with introduction to rules in science....After that we continue to start learning the first chapter about measurement and properties of matter. In this periods they learn about measurement unit for mass, length and time. They learn also about International Standard in Measurement Unit. We showed samples of instruments to measure mass, time and length.
-ayu-
Monday, y 8B and 8C
27-07-2009 - Physic
On monday, both of y 8B and 8C already given and introduced about rules in sciences class and laboratory.
After that they continue to learn about the first topic in physic...Magnetism
They already can make differences between electricity and magnetism..they know about magnetic field, and they can make differences in magnetized and unmagnetized.
-ayu-
On monday, both of y 8B and 8C already given and introduced about rules in sciences class and laboratory.
After that they continue to learn about the first topic in physic...Magnetism
They already can make differences between electricity and magnetism..they know about magnetic field, and they can make differences in magnetized and unmagnetized.
-ayu-
Wednesday, y 8A
29-07-2009
For year 8A, they will learn about physic and chemistry. But this day we start our periods with introduction to rules and syllabus. For chemistry y 8A already learn about chemical reaction.
Before start this chapter, we review again about the topic Chemical and Physical change they have learn before in y 7.
There is 6 kinds of Chemical reaction...in this day they already finish in learn Combustion and Synthesis reaction....
They will continue to another kinds of chemical reaction.
-ayu-
For year 8A, they will learn about physic and chemistry. But this day we start our periods with introduction to rules and syllabus. For chemistry y 8A already learn about chemical reaction.
Before start this chapter, we review again about the topic Chemical and Physical change they have learn before in y 7.
There is 6 kinds of Chemical reaction...in this day they already finish in learn Combustion and Synthesis reaction....
They will continue to another kinds of chemical reaction.
-ayu-
Monday, y 8
27-07-2009
For year 8, they will learn about physic and chemistry. For chemistry y 8C already learn about chemical reaction.
Before start this chapter, we review again about the topic Chemical and Physical change they have learn before in y 7.
There is 6 kinds of Chemical reaction...in this day they already finish in learn Combustion and Synthesis reaction....
They will continue to another kinds of chemical reaction.
-ayu-
For year 8, they will learn about physic and chemistry. For chemistry y 8C already learn about chemical reaction.
Before start this chapter, we review again about the topic Chemical and Physical change they have learn before in y 7.
There is 6 kinds of Chemical reaction...in this day they already finish in learn Combustion and Synthesis reaction....
They will continue to another kinds of chemical reaction.
-ayu-
Monday Year 10
Monday, 27-7-2009
Y 10, have introduction about science class, rules. For beginning, we start with the first chapter Elements, Compounds and Mixtures. In the class there is explanation about elements. Demonstration about the differences of pure substances and impure substances.
Students know about element which contain only one atom and element contain 2 same atoms. Next periods they will continue to learn about compounds and mixture and also their properties.
Y 10, have introduction about science class, rules. For beginning, we start with the first chapter Elements, Compounds and Mixtures. In the class there is explanation about elements. Demonstration about the differences of pure substances and impure substances.
Students know about element which contain only one atom and element contain 2 same atoms. Next periods they will continue to learn about compounds and mixture and also their properties.
Tuesday, July 28, 2009
Short Introduction to Science
This introduction is very important thing to do because every students should have clear understanding about science. We are aware or not science and technology already pervaded in every aspects of our daily life. In ancient times, human in every civilization obeyed and controlled by gods. But Socrates, Greek philosopher tried to break this chains. Since that time, science was born.
Today, science already revolutionized our ways of thinking, our ways of working, our ways of playing. Science can make impossible things become possible and real. So many inventions made us become like gods. We can create small sun on earth : atomic bomb. Biotechnology can make perfect clones. Our future belongs to science and technology experts.
So every student of Stella Maris should prepare themselves for incoming extreme future, where innovation and creativity become a must have tools to survive.
Today, science already revolutionized our ways of thinking, our ways of working, our ways of playing. Science can make impossible things become possible and real. So many inventions made us become like gods. We can create small sun on earth : atomic bomb. Biotechnology can make perfect clones. Our future belongs to science and technology experts.
So every student of Stella Maris should prepare themselves for incoming extreme future, where innovation and creativity become a must have tools to survive.
Rules in Science Class
Rules in the class:
- Don’t come late to the class. (Late means = when the bell ring, u are not in class) -1 for ur class participation
- Don’t use hp, ipod, novel, comic or anything doesn’t relate to the learning process.
- Teacher speaking, student hearing. (U can speak only to the teacher, to ur friend only in group discussion or in group work).
- don’t eat during the lesson time, but u can drink
- Can’t go to toilet during the lesson periods, only 2 students in 1 class 1 boy and 1 girl in different time.(only if u have more than 1 period).
- U can go out side the class after the teacher allow u to go out (even after the periods time is finished)
- Before u go from ur class, clean up ur desk, and arrange ur class like when u come, through all waste in the dust bin not in class floor.
- Put all ur handout, quiz papers, exercises work papers given by ur teacher in science in one folder.
- Bring ur science handout and ur science hand book (-1 for ur class participation)
Laboratory rules:
- Have to use lab coat
- Lateness come to lab will minus your point (-1 for ur class participation)
- Have to bring the used tools like calculator, ruler, pen, pencil, books, have to bring at least 2 blank papers for pre-lab test and record the practical’s result.
- Practical can be started after the instruction of the teacher.
- Don’t use any laboratory tools which not needed for the practical.
- Don’t use chemicals which not allowed by the teacher.
- Cleaning up the desk after ur practical finished (if not -2 for ur class participation)
- Ayu Putri Dewanti -
- Don’t come late to the class. (Late means = when the bell ring, u are not in class) -1 for ur class participation
- Don’t use hp, ipod, novel, comic or anything doesn’t relate to the learning process.
- Teacher speaking, student hearing. (U can speak only to the teacher, to ur friend only in group discussion or in group work).
- don’t eat during the lesson time, but u can drink
- Can’t go to toilet during the lesson periods, only 2 students in 1 class 1 boy and 1 girl in different time.(only if u have more than 1 period).
- U can go out side the class after the teacher allow u to go out (even after the periods time is finished)
- Before u go from ur class, clean up ur desk, and arrange ur class like when u come, through all waste in the dust bin not in class floor.
- Put all ur handout, quiz papers, exercises work papers given by ur teacher in science in one folder.
- Bring ur science handout and ur science hand book (-1 for ur class participation)
Laboratory rules:
- Have to use lab coat
- Lateness come to lab will minus your point (-1 for ur class participation)
- Have to bring the used tools like calculator, ruler, pen, pencil, books, have to bring at least 2 blank papers for pre-lab test and record the practical’s result.
- Practical can be started after the instruction of the teacher.
- Don’t use any laboratory tools which not needed for the practical.
- Don’t use chemicals which not allowed by the teacher.
- Cleaning up the desk after ur practical finished (if not -2 for ur class participation)
- Ayu Putri Dewanti -
Sunday, May 31, 2009
Final Exam Result Sem.II Grade 9
78001 Written test-80 lab work test-72
78003 Written test-78 lab work test-73
78002 Written test-76 lab work test-68
89080 Written test-33 lab work test-46
78004 Written test-35 lab work test-53
78005 Written test-24 lab work test-32
78006 Written test-31 lab work test-31
78007 written test-44 lab work test-39
89066 written test-42 lab work test-54
89081 written test-25 lab work test-29
78014 written test-31 lab work test-31
89107 written test-40 lab work test-49
89076 written test-26 lab work test-41
89063 written test-29 lab work test-40
89045 written test-49 lab work test-40
89092 written test-65 lab work test-48
78009 written test-61 lab work test-61
78010 written test-74 lab work test-68
78015 written test-82 lab work test-74
89085 written test-13 lab work test-49
89062 written test-31 lab work test-48
78012 written test-38 lab work test-67
78013 written test-35 lab work test-55
78016 written test-73 lab work test-76
78003 Written test-78 lab work test-73
78002 Written test-76 lab work test-68
89080 Written test-33 lab work test-46
78004 Written test-35 lab work test-53
78005 Written test-24 lab work test-32
78006 Written test-31 lab work test-31
78007 written test-44 lab work test-39
89066 written test-42 lab work test-54
89081 written test-25 lab work test-29
78014 written test-31 lab work test-31
89107 written test-40 lab work test-49
89076 written test-26 lab work test-41
89063 written test-29 lab work test-40
89045 written test-49 lab work test-40
89092 written test-65 lab work test-48
78009 written test-61 lab work test-61
78010 written test-74 lab work test-68
78015 written test-82 lab work test-74
89085 written test-13 lab work test-49
89062 written test-31 lab work test-48
78012 written test-38 lab work test-67
78013 written test-35 lab work test-55
78016 written test-73 lab work test-76
Final Exam Result Sem.II Grade 8
No. Student Number
1 78017 (53)
2 78018 (77)
3 78019 (32)
4 89043 (56)
5 89102 (27)
6 89084 (45)
7 89106 (73)
8 78020 (61)
9 89087 (11)
10 78021 (50)
11 78022 (38)
12 78023 (59)
13 89099 (59)
14 89095 (53)
15 78024 (47)
16 89103 (65)
17 78025 (76)
18 78026 (39)
19 89086 (88)
20 78029 (17)
21 89096 (29)
22 78027 (57)
23 78028 (42)
24 89071 (39)
25 89113 (15)
1 78017 (53)
2 78018 (77)
3 78019 (32)
4 89043 (56)
5 89102 (27)
6 89084 (45)
7 89106 (73)
8 78020 (61)
9 89087 (11)
10 78021 (50)
11 78022 (38)
12 78023 (59)
13 89099 (59)
14 89095 (53)
15 78024 (47)
16 89103 (65)
17 78025 (76)
18 78026 (39)
19 89086 (88)
20 78029 (17)
21 89096 (29)
22 78027 (57)
23 78028 (42)
24 89071 (39)
25 89113 (15)
Final Exam Result Sem.II Grade 7A
No. Student Number
1 89048 (78)
2 89053 (64)
3 89075 (31)
4 89038 (70)
5 89068 (52)
6 89058 (72)
7 89064 (51)
8 89070 (65)
9 89089 (66)
10 89054 (31)
11 89073 (78)
12 89083 (48)
13 89031 (42)
14 89061 (53)
15 89101 (75)
16 78030 (12)
17 89049 (71)
18 89051 (35)
19 89088 (24)
1 89048 (78)
2 89053 (64)
3 89075 (31)
4 89038 (70)
5 89068 (52)
6 89058 (72)
7 89064 (51)
8 89070 (65)
9 89089 (66)
10 89054 (31)
11 89073 (78)
12 89083 (48)
13 89031 (42)
14 89061 (53)
15 89101 (75)
16 78030 (12)
17 89049 (71)
18 89051 (35)
19 89088 (24)
Final Exam Result Sem.II Grade 7C
No. Student Number
1 89109 (28)
2 89108 (68)
3 89046 (58)
4 89037 (81)
5 89040 (67)
6 89039 (38)
7 89032 (71)
8 89056 (15)
9 89077 (20)
10 89078 (48)
11 89047 (13)
12 89067 (65)
13 89059 (81)
14 89097 (28)
15 89082 (57)
16 89104 (62)
17 89034 (56)
18 89098 (30)
19 89041 (72)
20 F.L (78)
1 89109 (28)
2 89108 (68)
3 89046 (58)
4 89037 (81)
5 89040 (67)
6 89039 (38)
7 89032 (71)
8 89056 (15)
9 89077 (20)
10 89078 (48)
11 89047 (13)
12 89067 (65)
13 89059 (81)
14 89097 (28)
15 89082 (57)
16 89104 (62)
17 89034 (56)
18 89098 (30)
19 89041 (72)
20 F.L (78)
Final Exam Result Grade 7B
No. Student Number
1 89094 (76)
2 89036 (74)
3 89105 (75)
4 89057 (60)
5 89091 (19)
6 89069 (54)
7 89074 (27)
8 89055 (24)
9 89100 (68)
10 89093 (15)
11 89042 (45)
12 89110 (32)
13 89044 (32)
14 89065 (78)
15 89050 (35)
16 89035 (85)
17 89090 (51)
18 89060 (64)
19 89052 (56)
1 89094 (76)
2 89036 (74)
3 89105 (75)
4 89057 (60)
5 89091 (19)
6 89069 (54)
7 89074 (27)
8 89055 (24)
9 89100 (68)
10 89093 (15)
11 89042 (45)
12 89110 (32)
13 89044 (32)
14 89065 (78)
15 89050 (35)
16 89035 (85)
17 89090 (51)
18 89060 (64)
19 89052 (56)
Monday, April 27, 2009
Monday, March 23, 2009
Grade 8 class activity report-Monday, March 23rd 2009
Topic: Electromagnetism
Duration: 1 period
Activity:
- the class activity began by asking students to recall about magnetism that they have learned
and sharing what they know about magnet. Then I began to do brainstorming with the
students about the definiton of "electromagnetism" (it derives from the word electro and
magnet).
- after brainstorming, I continued to explain about electromagnetism in details. For this topic,
students are going to make their own electromagnet. This activity will be done tomorrow
(Tuesday, March 24th 2009) in groups. This activity is based on Oersted's Experiment.
- As the closing, I asked students to prepare the materials needed for tomorrow activity.
Grade 8-Electromagnetism (Lab activity on Tuesday, March 24th 2009)
ELECTROMAGNETISM
Oersted's Experiment
In 1819, a Danish scientist named Hans Christian Oersted discovered a close relationship between electricity and magnetism with this experiment. Oersted's discovery led to the study of electromagnetism. Try Oersted's experiment yourself!
Materials You Will Need:
- Two batteries (size D)
· - Small, non-metallic bowl
· - Needle
· - Modeling clay
· - Switch (you can make the switch from paper clips)
· - Tape (cellotape)
·
Steps to Create Oersted's Experiment:
-Stroke needle 50 times from center to one end with
magnet. Tape on cork and place in bowl of water.
- Watch direction of needle when you move magnet n near it.
- Place wire over top of dish. Secure it with clay.
- Connect one end of wire to switch.
- Connect other wire end from switch to negative (-)
lead of your batteries.
- Connect other wire end from bowl to positive (+) lead
of your batteries.
- Close switch. Observe results.Oersted's Experiment
In 1819, a Danish scientist named Hans Christian Oersted discovered a close relationship between electricity and magnetism with this experiment. Oersted's discovery led to the study of electromagnetism. Try Oersted's experiment yourself!
Materials You Will Need:
- Two batteries (size D)
· - Small, non-metallic bowl
· - Needle
· - Modeling clay
· - Switch (you can make the switch from paper clips)
· - Tape (cellotape)
·
Steps to Create Oersted's Experiment:
-Stroke needle 50 times from center to one end with
magnet. Tape on cork and place in bowl of water.
- Watch direction of needle when you move magnet n near it.
- Place wire over top of dish. Secure it with clay.
- Connect one end of wire to switch.
- Connect other wire end from switch to negative (-)
lead of your batteries.
- Connect other wire end from bowl to positive (+) lead
of your batteries.
You've done the experiment that Oersted did— and have shown that there's a magnetic field around the circuit wire when the electric current is flowing. When the current flows, the magnetic needle is deflected at right angles to the circuit wire.
This experiment is one of the most important in the utilization of electric power—it led to the discovery of electromagnetism and the development of the electric motor.
Tuesday, March 17, 2009
Chapter 4 Grade 7: States of Matter
States of Matter & Physical Change
(Course Outline)
A. The Particulate Model of Matter
A.1 What is Matter Made of?
A.2 Particulate Models in Science
A.3 Investigate Solids, Liquids and Gases and Their
Inter-conversion
Time allotment: Tue, March 17 – Tue, march 24, 2009
B. Physical Change
B.1 Changes around Us
B.2 the Distinction between Physical and Chemical
Changes
B.3 Use Simple Kinetic Particle Theory to Explain
Changes of State, Dissolving and Diffusion
B.3 Interaction of Matter and Energy
Time allotment: Tue, March 24 – Fri, April 2, 2009
C. Methods of Separating Mixtures
C.1 Variety of Methods of Obtaining Pure Substances
from Different Mixtures
C.2 Evaporation
C.3 Filtration
C.4 Distillation
Time allotment: Tue, April 14– Fri, April 24, 2009
(Course Outline)
A. The Particulate Model of Matter
A.1 What is Matter Made of?
A.2 Particulate Models in Science
A.3 Investigate Solids, Liquids and Gases and Their
Inter-conversion
Time allotment: Tue, March 17 – Tue, march 24, 2009
B. Physical Change
B.1 Changes around Us
B.2 the Distinction between Physical and Chemical
Changes
B.3 Use Simple Kinetic Particle Theory to Explain
Changes of State, Dissolving and Diffusion
B.3 Interaction of Matter and Energy
Time allotment: Tue, March 24 – Fri, April 2, 2009
C. Methods of Separating Mixtures
C.1 Variety of Methods of Obtaining Pure Substances
from Different Mixtures
C.2 Evaporation
C.3 Filtration
C.4 Distillation
Time allotment: Tue, April 14– Fri, April 24, 2009
Sunday, March 8, 2009
6 Levels of Learning
Here are the 6 levels of learning..for students and teachers as well:
1. I've heard of it-memorize the info
2. I can repeat
3. I can apply it in the same context
4. I can apply it in the different context
5. I can break it down and recognize it
6. I can teach it...
GOOD LUCK ALL!
Sunday, February 22, 2009
Grade 9-Forces
FORCES
Force can be defined as a push or a pull. (Technically, force is something that can accelerate objects.) For example, when you throw a baseball, you apply a force to the ball. Force is measured by N (Newton). A force that causes an object with a mass of 1 kg to accelerate at 1 m/s is equivalent to 1 Newton.
Section 2. Newton's First Law of Motion
You will have to learn a new terminology here: net force. Net force is the sum of all forces acting on an object. For example, in a tag of war, when one team is pulling the tag with a force of 100 N and the other with 80 N, the net force would be 20 N at the direction of the first team (100 N - 80 N = 20 N).
When you slide your book on floor it will stop soon. When you slide it on icy surface, it will travel further and then stop. Galileo believed that when you slide a perfectly smooth object on a frictionless floor the object would travel forever.
Isaac Newton developed the idea of Galileo further. He concluded that an object will remain at rest or move with constant velocity when there is no net force acting on it. This is called Newton's First Law of Motion, or Law of Inertia
Newton's First Law deals with an object with no net force. Newton's Second Law talks about an object that has net force. It states that when the net force acting on an object is not zero, the object will accelerate at the direction of the exerted force. The acceleration is directly proportional to the net force and inversely proportional to the mass. It can be expressed in formula
F = ma
From this formula, we can say that force is something that accelerates an object.
Mass and weight are different in physics. For example, your mass doesn't change when you go to the Moon, but your weight does. Mass shows the quantity, and weight shows the size of gravity.
If you know your mass, you can easily find your weight because
W = mg
where:
W is weight in Newton (N),
m is mass in kg, and
g is the acceleration of gravity in m/s2.
If your mass is 70 kg on Earth, your weight isW=(70 kg)(9.8 m/s2) = 686 N.
Weight is measured by Newton (N).
You will have to learn another vocabulary before you proceed: the normal force. The normal force acts on any object that touches surface (either directly or indirectly). The normal force would be applied on a ball on a table, but not on a ball in the air, for instance. It always acts perpendicularly to the surface. The formula to calculate the normal force is
FN = - mg
where:
FN is the normal force in Newton (N),
m is the mass in kg, and
g is the gravitational force in m/s2.
For example, the normal force acting on a 70 kg-person would beFN = - (70 kg)(-9.8 m/s2) = 686N
In previous chapters, we studied how objects move. In this chapter, we will study why objects move as they do. We will study Newton's Laws of Motion, which explain the relationship between acceleration and force. We will also use Newton's Laws for problem solving.
1. What is a Force?
1. What is a Force?
6. Friction
Force can be defined as a push or a pull. (Technically, force is something that can accelerate objects.) For example, when you throw a baseball, you apply a force to the ball. Force is measured by N (Newton). A force that causes an object with a mass of 1 kg to accelerate at 1 m/s is equivalent to 1 Newton.
Section 2. Newton's First Law of Motion
You will have to learn a new terminology here: net force. Net force is the sum of all forces acting on an object. For example, in a tag of war, when one team is pulling the tag with a force of 100 N and the other with 80 N, the net force would be 20 N at the direction of the first team (100 N - 80 N = 20 N).
When you slide your book on floor it will stop soon. When you slide it on icy surface, it will travel further and then stop. Galileo believed that when you slide a perfectly smooth object on a frictionless floor the object would travel forever.
Isaac Newton developed the idea of Galileo further. He concluded that an object will remain at rest or move with constant velocity when there is no net force acting on it. This is called Newton's First Law of Motion, or Law of Inertia
Newton's First Law deals with an object with no net force. Newton's Second Law talks about an object that has net force. It states that when the net force acting on an object is not zero, the object will accelerate at the direction of the exerted force. The acceleration is directly proportional to the net force and inversely proportional to the mass. It can be expressed in formula
F = ma
where:
F is the net force in N,
m is the mass of an object in kg and
a is its acceleration in m/s2.
F is the net force in N,
m is the mass of an object in kg and
a is its acceleration in m/s2.
From this formula, we can say that force is something that accelerates an object.
Section 4. Newton's Third Law of Motion
When you kick the wall in your room, you will probably end up hurting your foot. Newton's Third Law of Motion can explain why: when one object applies a force on a second object, the second object applies a force on the first that has an equal magnitude but opposite direction. In other words, when you kick the wall, the wall kicks you back with equal force. As a result you will get hurt. These forces are called action-reaction forces.
Remember when you kick the wall, you exerts force on the wall. When the wall kicks you back, it exerts force on you. Therefore, the net force on the wall is not zero and the net force on your foot is not zero neither.
When you kick the wall in your room, you will probably end up hurting your foot. Newton's Third Law of Motion can explain why: when one object applies a force on a second object, the second object applies a force on the first that has an equal magnitude but opposite direction. In other words, when you kick the wall, the wall kicks you back with equal force. As a result you will get hurt. These forces are called action-reaction forces.
Remember when you kick the wall, you exerts force on the wall. When the wall kicks you back, it exerts force on you. Therefore, the net force on the wall is not zero and the net force on your foot is not zero neither.
Mass and weight are different in physics. For example, your mass doesn't change when you go to the Moon, but your weight does. Mass shows the quantity, and weight shows the size of gravity.
If you know your mass, you can easily find your weight because
W = mg
where:
W is weight in Newton (N),
m is mass in kg, and
g is the acceleration of gravity in m/s2.
If your mass is 70 kg on Earth, your weight isW=(70 kg)(9.8 m/s2) = 686 N.
Weight is measured by Newton (N).
You will have to learn another vocabulary before you proceed: the normal force. The normal force acts on any object that touches surface (either directly or indirectly). The normal force would be applied on a ball on a table, but not on a ball in the air, for instance. It always acts perpendicularly to the surface. The formula to calculate the normal force is
FN = - mg
where:
FN is the normal force in Newton (N),
m is the mass in kg, and
g is the gravitational force in m/s2.
For example, the normal force acting on a 70 kg-person would beFN = - (70 kg)(-9.8 m/s2) = 686N
Grade 8 Parallel circuit
Parallel circuits
If two or more components are connected in parallel they have the same potential difference (voltage) across their ends. The potential differences across the components are the same in magnitude, and they also have identical polarities. Hence, the same voltage is applicable to all circuit components connected in parallel. The total current I is the sum of the currents through the individual components, in accordance with Kirchhoff's circuit laws. The current in each individual resistor is found by Ohm's law.
Grade 8 - Series Circuit
In electronics, components of an electronic circuit can be connected in series or in parallel. Components connected in series are connected along a single path, so the same current flows through all of the components. Components connected in parallel are connected such that there are multiple independent paths along which the current can flow; in other words, the current is split among the different paths. A circuit composed solely of components connected in series is known as a series circuit; likewise, one connected completely in parallel is known as a parallel circuit.
Series circuits are sometimes called current-coupled or daisy chain-coupled. The current that flows in a series circuit will flow through every component in the circuit. Therefore, all of the components in a series connection carry the same current.
http://http://en.wikipedia.org/wiki/Series_and_parallel_circuits
Thursday, February 19, 2009
Grade-7 How hydroeletricity works
So just how do we get electricity from water? Actually, hydroelectric and coal-fired power plants produce electricity in a similar way. In both cases a power source is used to turn a propeller-like piece called a turbine, which then turns a metal shaft in an electric generator , which is the motor that produces electricity. A coal-fired power plant uses steam to turn the turbine blades; whereas a hydroelectric plant uses falling water to turn the turbine. The results are the same.
Here are steps of how hydroelectricity works:
1. A hydropower plant uses falling water as stored energy. Water from the reservoir (A) passes through the penstock (a large pipe that carries water from the reservoir to turbines in the powerhouse) (B) to enter the powerhouse.
2. The flowing water turns the propeller-like water wheel or turbine (C), which is connected by a shaft to the generator (D), which spins and produces electricity.
3. As water leaves the turbine, it is discharged through the draft tube (E), where it enters the tailrace (F) and returns unaltered to the river below the dam.
4. The electricity produced by the spinning generator (D) is conducted to the power transformer (G), where the voltage is increased.
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