dialogue teacher and student

The scientific approach is the scientific framework of learning that is carried by the Curriculum 2013. Steps on a scientific approach is a form of adaptation of scientific steps in science. The learning process can be matched by a scientific process, therefore the 2013 Curriculum mandates the essence of a scientific approach in learning. The scientific approach is believed to be a golden tool for the development and development of students' attitudes, skills, and knowledge. In approaches or work processes that meet the scientific criteria, scientists are more concerned with inductive reasoning than deductive reasoning. Among the saintific approaches are:

1. comucating skill

Communication is the main activity of human in everyday life. Communication skills are the ability, intelligence, and communication skills. Communication is the capital and key suses in association and career because only with communication a good relationship can be built and nurtured.2. Argumentation skill

Generating counterarguments is an important argument skill.Thinking about counterarguments will lead to a more thoughtful and informed consideration. For example, if you have to write an essay or an argumentative paper or if you are preparing a debate. For a more considered judgment on moral issues, one which addresses moral counterarguments, it may be useful to know something about ethical dilemmas and moral values.3. Problem solving skill

Most problem-solving skills are developed through everyday life and experience. However, the following interests and activities may be useful in applying to high-level skills such as engineering, IT, operational research and some areas of finance.'Mind games' such as cryptic crosswords, Sudoku, chess, bridge, etc;Computer games - the best of these can involve strategic planning, critical and statistical analysis and assessing the pros and cons of different courses of action;'Practical' interests such as programming, computer repairs, car maintenance, or DIY;Working with sound or lighting equipment for a band, event or show;Academic study: evaluating different sources of information for the essays, designing and constructing a 'microshelter' for an architecture project; Setting up a lab experiment.4. Incuiry skill

One method of teaching that is very kontruktivistik is the method of inquiry (investigation). In this method students are really involved to actively think and find the understanding they want to know. In this method of learning students are involved in the process of discovery through data collection and hypothesis testing. In general, Inquiry is the process by which scientists ask questions about the nature of this world and how they systematically seek answers.5. Contracting skill

The ability of contracting is the ability to be able to arrange or process everything so that it can be a capability that helps in concluding and so on.

Here is an example of a dialogue between teacher and student about colligative properties of solution


Mrs. Shabrina              : okay class in this morning we will discuss about                                                        carbohydrate, who know what is carbohydrate?

Randi                          : carbohydrate is biological molecule

Dina                            : it’s contain of carbon atom

Mrs. Shabrina              : yes, any one?

(silent)

Mrs. Shabrina              :  a carbohydrate is a biological molecule consisting of                                                 carbon, hydrogen, and oxygen atoms. With the empirical                                            formula Cn(H₂O)n. Carbohydrate are technically hydrates                                      of carbon. Structurally it is more accurate to view them as                                       polyhydroxy aldehydes and ketones. The term is most                                              common in biochemistry, where it is a synonym of                                                    “saccharide”. Are you know why the synonym is                                                                saccharide?

Doni                            : i just know that saccharide is the name of latin from sugar.

Mrs. Shabrina              : yes doni, you are right. Saccharide a group that includes                                          sugar, strach, an cellulose. The saccharides are divide into                                          four chemical groups: monosaccharides, disaccharides,                                               oligosaccharides, and polysaccharides.

Laras                           : mrs, what the different from those?

Mrs. Shabrina              : in general, they exhibit much of the same properties, such                                        as water solubility and sweet taste. Both consist of only                                                 carbon, hydrogen, and oxygen in varying proportions. Did                              you know where we can find carbohydrate?

They all shout for this question, look like much interested. And i choose who the first rise hand.

Dara                            : we can found carbohydrate in rice, potatos, bread.

Nirvana                       : we can found in fruits, vegetables, milk

Mrs. Shabrina              : yes all you said right. Carbohydrates are found in wide                                            variety of foods. The important sources are sereals (wheat,                             maize, rice), potatos, sugarcane, fruits, table sugar, bread,                                               nilk, etc.

Dina                            : but mrs, i’ve read there is other name of carbohydrate. That                                     called carbohydrate complex and simple, would you                                                   explain about that?

Mrs. Shabrina              : okay thank you it’s good question. Carbohydrate are called                                     simple or complex, dipending sugars found naturally in                                              foods. Such as fruits, vegetables, milk.Complex                                                         carbohydrates include whole grain breads and sereals.

                                      The difference between a simple nd complex carb is in how                                     quickly it is digested and absorbed. Most carbohydrates can                                      be broken dwon by digetion into glucose. Complex                                                carbohydrates, are starches formed by longer saccharide                                             chains, wich means they take longer to break down.

                                      Okay class i think our times is over, and next weeks we will                                     do experiment to know food contains carbohydrate. Okay                                              see you next week class, bye.

All students                 : thank you mrs see you.  

  

vocabulary in chemistry

1.      Acetone

is a carbonyl compound that is found in the atmosphere as a reactive gas. Acetone is considered to be a volatile organic compound (VOC), which is emitted into the atmosphere by industrial processes. Acetone has been linked to the formation of ozone in the troposphere due to the fact that it is a source of free radicals.

2.      Acidification

This process happens when compounds like ammonia, nitrogen oxides and sulphur dioxides are converted in a chemical reaction into acidic substances. Most of the compounds are a direct result of air pollution.

3.      Acid-pulse (dry deposition)

deposit of powder - like substance over the ground surface; especially effecting plant leaves; that when contacted by water has a very low pH.

4.      Addition reaction

A reaction in which two atoms or groups of atoms are added to a molecule, one on each side of a double or triple bond

5.      Antinodes

points of constructive interference between two waves

6.      Backscattering

      Process by which up to 25% of radiant energy from the sun is reflected or scattered           away from the surface by clouds. Serves the greatest importance in the Atmospheric          Heat Budget. Large errors in the assumed value of this variable may have important   effects on computer models of the atmosphere.

7.      Bayer process

      used to obtain aluminum from bauxite

8.      Benzene

      is an aromatic hydrocarbon. It can be found in the air by several different ways of             transmission. It can be produced for use with plastic or produced through the burning           of fossil fuels.

9.      Binary compound

      A compound consisting of two elements;      may be ionic or covalent.

10.  Buffer solution

Solution that resists change in pH; contains either a weak acid and a soluble ionic salt of the acid or a weak base and a soluble ionic salt of the base.

11.  Coeffecients

 Numbers in front of each substance in a equation.

12.  Compound

 substance in which the atoms of 2 or more elements are combined.

13.  Combustion Reaction 

 Substance reacts with oxygen to make heat and light.

14.  Covalent Bond 

 Attraction formed when elements share electrons.

15.  Chemical Formula

 A formula that shows what elements are in a compound and what it will become.

16.  Distillation 

 A process for separating substances by evaporating a liquid and recondensing its vapor.

17.  Diffusion 

 Spreading of particles throughout a given volume until they are distributed.

18.  Diatomic Molecule

 Consists of 2 atoms of the same element in a covalent compound.

19.  Double Displacement Reaction 

 Two elements replace another to make a product.

20.  Denature

There are two common meanings for this in chemistry. First, it can refer to any process used to make ethanol unfit for consumption (denatured alcohol). Second, denaturing can mean breaking down the three-dimensional structure of a molecule, such as a protein is denatured when exposed to heat.

21.  Electrolyte An electrolyte 

 ionic compound that dissolves in water to produce ions, which can conduct electricity. Strong electrolytes completely dissociate in water, while weak electrolytes only partially dissociate or break apart in water.

22.  Element 

 If all the atoms in a substance has the same identity it becomes {blank}.

23.  Electrons 

 Particles in a atom with a negative charge.

24.  Electron Cloud

 Area around a nucleus where electrons are mostly found.

25.  Electron Dot Diagram 

 Uses the symbol of the element and dots to represent electrons.

26.  Metallic Bonding   

Positively charged metallic ions surrounded by a electron cloud.

27.  Metals 

 Good conductors of heat and electricity.

28.  Metalloids 

 Has properties of both nonmetals and metals.

29.  Malleable 

 Can be hammered.

30.  Molecule 

 A neutral molecule that forms as a result of electron sharing.

31.Nonmetals 

 Usually gasses or brittle solids at room temperature.

32.  Nucleus  

The center of a atom.

33.  Neutrons  

 Particles in a atom with no charge.

34.  Oxidation Number 

Tells you how many electrons an atom has gained or lost.

35.  Physical Property

 Characteristic of a material you can observe without changing the identity.

36.  Physical Change  

 A change in size, shape, or state.

37.  Periodic Table

 A table filled with elements in order of atomic numbers, etc.

38.Pressure 

Force exerted per area. (Formula)

39.  Polyatomic Ion 

Positively or negatively charged, covalently bonded group.

40.                        Additivies

 something that is added, as one substance to another, to alter or improve the general quality or to counteract undesirable properties

41.  Affinity

 Affinity is the tendency of a molecule to associate with another. The affinity of a drug is its ability to bind to its biological target (receptor, enzyme, transport system, etc.)

show cause and effect in chemical reaction

 Buffer

Why do we care about the pH of a solution? Most of the body’s cells only function within a very narrow range near neutral pH. Enzymes that help us grow and reproduce, break down the food we eat, and assist in other vital functions each work within a specific, narrow pH range. To help maintain this pH, buffers are present in nearly all living solutions.

A buffer is any substance that minimizes change in the pH of a solution. Most buffers consist of a combination of a weak acid and the weak base, where the base is the anion remaining after the weak acid dissociates (separates) to release H⁺ ions. This may sound confusing, but it is actually a fairly simple back and forth reaction where the buffer acts as a “friend” to H⁺ ions when necessary, but also to OH^- ions when necessary, maintaining a constant balance in the pH value.

Imagine a family with three children. If the oldest child and the youngest child tend to fight a lot, the middle child often acts as a “buffer” between the two fighting children. When we say buffer in this situation, we mean that the middle child will play older kid games at times when the oldest child needs attention and play simpler, younger kid games at times when the youngest child needs attention. By shifting to meet the needs of each child, the middle child buffers the situation, resulting in less angry children. This may not be optimal for the middle child buffer, but it makes the parents happier!     

if we add a strong acid or strong base to water, the pH will change dramatically. For instance, adding a strong acid such as HCl to water results in the reaction HCl + H₂O → H₃O⁺ + Cl^-. In other words, the proton (H⁺) from the acid binds to neutral water molecules to form H₃O⁺ raising the concentration of H⁺. The resulting large concentration of (H⁺) makes the solution more acidic and leads to a dramatic drop in the pH.

                                    

Solid NaOH consists of Na⁺ and OH^- ions packed into a crystalline lattice. When this solid is added to water, the ions float apart leading to extra OH^- ions in the water: NaOH → OH^- + Na⁺. The resulting large concentration of OH^- makes the solution more basic and leads to a dramatic increase in the pH. (Remember that since the product of concentrations, [OH^-][H⁺], remains fixed at K_w=10^-14, as the concentration of OH^- ions goes up, the concentration of H⁺ ions goes down.)     

                               

If we mix a weak acid (HA) with its conjugate base (A^-), both the acid and base components remain present in the solution. This is because they do not undergo any reactions that significantly alter their concentrations. The acid and conjugate base may react with one another, HA + A^- → A^- + HA, but when they do so, they simply trade places and the concentrations [HA] and [A^-] do not change. In addition, HA and A^- only rarely react with water. By definition, a weak acid is one that only rarely dissociates in water (that is, only rarely will the acid lose its proton H⁺ to water). Likewise, since the conjugate base A^- is a weak base, it rarely steals a proton H⁺ from water.

So, the weak acid and weak base remain in the solution with high concentrations since they only rarely react with the water. However, they are very likely to react with any added strong base or strong acid.

                               

If a strong base is added to a buffer, the weak acid will give up its H⁺ in order to transform the base (OH^-) into water (H₂O) and the conjugate base: HA + OH^- → A^- + H₂O. Since the added OH^- is consumed by this reaction, the pH will change only slightly.

                        

If a strong acid is added to a buffer, the weak base will react with the H⁺ from the strong acid to form the weak acid HA: H⁺ + A^- → HA. The H⁺ gets absorbed by the A^- instead of reacting with water to form H₃O⁺ (H⁺), so the pH changes only slightly.

                                

Buffers are extremely important to living organisms because most biochemical processes proceed normally only when the pH remains within a fairly narrow range. An excess of H⁺ or OH^- can interfere with the structure and activity of many biomolecules, especially proteins. Therefore, buffers are commonly used in living organisms to help maintain a relatively stable pH. In humans, for example, buffers act to maintain blood pH between 7.35 and 7.45 even though acids and bases are continually being added to and removed from the blood as it travels through the body. The 3 main buffer systems in our bodies are the bicarbonate buffer system, the phosphate buffer system, and the protein buffer system.

In the laboratory, molecular and cellular biologists make extensive use of buffers to stabilize the pH of aqueous solutions. When studying biomolecules in a test tube, the biomolecules may be altered or may behave in ways that are uncharacteristic of their natural behavior if they are in a solution with a pH that is significantly different from the pH of their natural environment.

Reference

http://chemcollective.org/activities/tutorials/buffers/buffers3act

https://en.wikipedia.org

https://dlc.dcccd.edu/biology1-2/ph-and-buffers

http://examples.yourdictionary.com/cause-and-effect-examples.html]