Dialogue Between Teacher and Students with a Scientific Approuch
The application of a scientific approach will be the challenge of teachers through the development of 7 activities of students that is observing, asking, trying, processing, tasting, reasoning, and creating.
The dialogue :
On monday morning chemistry class prepare the references to study about endothermic and exothermic reactions before the the teacher comes.
On monday morning chemistry class prepare the references to study about endothermic and exothermic reactions before the the teacher comes.
*teacher enter the class*
Teacher: Good morning everybody, in this morning we will discuss about corrosion. So who know the definition of corrosion?
Student : *hand’s up* I know sir
Teacher : Yes, please
Student : Corrosion is a natural process, which converts a refined metal to a more chemically-stable form, such as its oxide, hydroxide, or sulfide
Teacher : thats good, and It is the gradual destruction of materials (usually metals) by chemical and/or electrochemical reaction with their environment. Corrosion engineering is the field dedicated to controlling and stopping corrosion.
student :*hand’s up* I'm sorry ser, I do not understand corrosion, can you explain in more detail?
Teacher : Of Course, In the most common use of the word, this means electrochemical oxidation of metal in reaction with an oxidant such as oxygen or sulfur. Rusting, the formation of iron oxides, is a well-known example of electrochemical corrosion. This type of damage typically produces oxide(s) or salt(s) of the original metal, and results in a distinctive orange colouration.
Student : *hand’s up*, so Whether corrosion has a negative impact on daily life?
Teacher : yes, you are right.In everyday life, corrosion can be encountered in various metals. Buildings and electronic equipment that use metal components such as zinc, copper, iron-steel and so on can all be attacked by this corrosion. Zinc for the roof can leak due to corrosion.Similarly, PJU poles and baliho poles can not be free from corrosion problems. The poles can be vulnerable due to corrosion and will be fatal if the pole collapses. Not infrequently we hear the news of accidents on the road due to crashed power poles collapsed or struck billboards collapsed due to corrosion.
Student : *hand’s up*, so How to prevent ser?
Teacher :okey, Prevention of Preventing contact with oxygen and / or water, Cathode protection (sacrifice of anode),Make alloy or stainless metal alloy,Painting,Tin Plating (coating with tin),Galvanizing (coating with Zink), Cromium Plating (coating with chromium).
*the bells are ringing*
Teacher : Ok, I think It’s enough for today. See you on the next lesson and don’t forget to prepare the references about colloid for next week.
All of students : Ok sir!
Explain the chemical reaction of the corrosion event? What effect if we still keep using the stuff that has been corrosion. Example: rusty spoon.
BalasHapusThe item can not be used again, and if the spoon is still bus cleaned then it can still be used
HapusA piece of iron that undergoes oxidation process will rust, wear out and disappear. Likewise with the human body. Naturally, slowly but surely the human body will "rust", aging and death. What is the cause of rust on the human body? The answer, free radicals.
Free radicals are molecules that have free electrons (unpaired) on their outer shells. Free radicals are rust that damage our bodies slowly and are believed to be closely related to the occurrence of premature aging, facial spots, cancer, heart, blood vessels, strokes, cataracts and various other diseases.
Free radicals can be described as burning residues on machines that produce black soot that contaminates spark plugs and at some stage will cause damage to the engine. In the human body, the food and drinks we consume daily are the fuel. Once through the process of digestion, food will be converted into energy through the process of metabolism in our body cells.
Antioxidant-rich foods enter the body and are digested in the digestive system. It is through the bloodstream that antioxidants enter the cells and give free electrons to free radicals. Antioxidants can also repair the body cells that are destroyed by free radicals. You can meet the need for natural antioxidants through the foods we consume daily, such as vegetables and fruits that contain many antioxidants to minimize damage to body cells.
Why gold can't corroted
BalasHapusThe electrons in iron are very easy to escape (out of the metal), while the electrons in gold prefer to be inside the metal. That is why, when iron meets with water and oxygen, the iron electrons will easily escape and react to form rust.
HapusPlease show me,The reaction when Iron Is corroting
BalasHapusCorrosion as a whole is an electrochemical process. In iron corrosion, certain parts of iron as anode, where iron undergoes oxidation.
HapusFe(s) à Fe2+(aq) + 2e–
The electrons released in the oxidation will flow to other parts to reduce oxygen.
O2(g) + 2 H2O(l) + 4e– à 4 OH–(l)
What kind of learning you use in the lesson?
BalasHapusDirect Learning Model
HapusThe direct learning model is not the same as the lecture method. The direct learning model is one of the learning models that can help students learn basic skills and obtain information that can be taught step by step. Direct learning model is a learning model designed specifically to develop learning about procedural knowledge and declarative knowledge that is well structured and can be studied step by step.
Direct learning models require detailed planning and execution, especially on task analysis. Although the direct learning model is teacher-centered, it must still ensure student involvement. Learning environments should be created that are oriented towards the tasks that learners must accomplish.
Some advantages of direct learning model such as among others follows.
A. The material presented is relatively more for a short time.
B. For procedural material, the direct learning model is easy to follow.
While the weakness of the direct teaching model, among others, if the learning is not well designed, then this model will be filled with lecture methods that do not train students to be independent, and construct their own knowledge, and can make students bored quickly.