Showing posts with label Ringkasan Materi Ilmu Pengaetahuan Alam (IPA). Show all posts
Showing posts with label Ringkasan Materi Ilmu Pengaetahuan Alam (IPA). Show all posts

The Chemical Substances Hazardous ang dangerous for humans

Chemical Substances Hazardous There are chemicals that are harmful to humans , among others :
a. Aluminum sulfate (also 4 )
Shaped white crystals , soluble in water . Sulfatdigunakan aluminum instead of alum .
b concentrated ammonia ( NH 4OH )
Concentrated solution of ammonia gas in water , if exposed to the skin and eyes can cause irritation . In vapor form may interfere with breathing . Ammonia concentrated very dangerous if swallowed .
c . Sulfuric acid ( H 2SO 4 )
Sulfuric acid is a colorless liquid , toxic and highly corrosive . Sulfuric acid can cause burns to skin , eyes , and can damage clothing .
d . Hydrochloric acid ( HCl )
Hydrochloric acid is a liquid , toxic , corrosive , and is in vapor form can damage the skin , eyes , and respiratory apparatus .
e . Ethanol ( C 2H3OH )
Ethanol is often called alcohol . Ethanol has flammable properties and is used as a solvent .
ff f ... Or ormalin malin for 40 % ( HCHO ) Formalin is toxic , either liquid or gas . Formalin is used to kill pests .
g . Klorofrom ( CHCl 3 )
Chloroform is a colorless liquid and is toxic . Chloroform is used as an anesthetic in the laboratory .
h . Beer Metilin Blue
Metilin intangible dark blue solid . These chemicals are used as coloring the cell nucleus .
i . Sodium hydroxide ( NaOH )
Sodium hydroxide is a white solid , easy to absorb moisture , air , toxic and corrosive . Sodium hydroxide including hazardous material that can cause burns to skin and eyes .
j . Cobalt chloride ( CoCl 6H2O )
Cobalt chloride is a solid , red crystal , it is very easy to absorb water , and can bind water vapor . Cobalt chloride is used to test the air humidity .
k . Sodium Chloride ( NaCl )
Sodium chloride is a white solid substance , shaped crystals . Sodium chloride is also known as table salt .

how to use a microscope properly

How do I use a microscope correctly ? To be able to use a microscope to properly consider the following steps :
a. Finding the visual field by adjusting irradiation to produce the visual field is the mengatu mirror while looking at that light into the eyepiece to the diaphragm , resulting in optimum reflectivity . The bright part is called the spherical field of view .
b Adjust the focus of the microscope with a magnification weak or shadows on the table Put preparations preparations , clamped with tongs as he watched from the side of the tube microscope microscope lowered with a rough player , do careful not to touch the objective lens preparations . Then look through the eyepiece and slowly microscope Bring up the tube so that the object is clearly visible. Once the object looks , smooth player to rotate forward or backward to get the best possible image . Magnification of the microscope is obtained by multiplying the numbers in the objective lens with the numbers listed in the ocular lens . For example, the objective lens 5x 10x 50x eyepiece then perbesarannya .
c . Adjusting the focus of the microscope ( shadow with powerful magnification ) To obtain the shadow , can be done by changing the objective lens has a magnification weaker by the stronger . For example, an objective lens with a magnification of 5x to 10x or 40x replaced by rotating the revolver until you hear terdetak . Smooth player rotated forward or backward in order to obtain a clearer object .
d . Set the microscope to position stored Upon completion microscope is used , adjust the microscope with position ready to be stored in the following way :
1 ) Tube microscope is raised .
2 ) Mixture taken .
3 ) The objective lens is the weakest lowered as low as played exactly the microscope until the hole table .
4 ) The diaphragm is closed again .
5 ) Condenser lowered and mirrors in an upright position .
6 ) Raise the microscope with the right hand carefully holding the arm and prop feet mikrokop microscope with the left hand and then put into place and locked .
How to make preparations :
1 ) Make preparations without incision : To make a wet mount without an incision , for example on
time observation of microorganisms present in water . How: water to be observed , taken with a Pasteur pipette and placed on glass objective and cover with a glass cover , observe with a microscope .
2 ) Make an incision preparations : Make preparations in organ organism , for example cross-section of leaves , stems , roots , muscles , etc. How: slashing organ as thin as possible , to make a good and thin incision with an instrument called a microtome , but if not using a microtome can have razor sharp .

microscope

In the history of the microscope discovered 16th century thanks to the discovery of a scientist , living things
which can not be seen can be seen by using a tool . The tool is a microscope , which allows one to observe objects or beings that are not able to be seen with the naked eye . The microscope consists of two parts , namely :

1 . In the mechanical part mechanical part consists of :
a. Feet serve to support the microscope microscope .b . Pillar or joint inclination as a liaison between the legs with arms microscope .c . Regulatory condenser condenser serves to draw down .d . The condenser is used to focus light onto the object being observede . Arm microscope microscope serves as a handle .f . Hinge arm drive serves as a liaison with legs microscopeg . Counter preparations serves to put the preparations to be observed .h . Preparations or preparations clamp holder serves to clamp the preparations to be observed so as not to shift .i . Serves to connect the tube between the objective lens and eyepiece .j . Revolver serves to place the objective lens .k . Screw rough player function for quickly moving the microscope tube from top to bottom .l . Screw player works fine for the tube to move up and down slowly . This tool is used if the object has been focused by turning a rough player .
2 . Optical parts optical section consists of :
a. Two pieces of mirror , a flat mirror and a concave mirror . Mirror function is to search for , collect , and directs the light to the object observed . Flat mirrors for enough light source and a concave mirror to a less bright light source .b . Diaphragm , serves to regulate the extent of the mirror reflected light toward the eye .c . Objective lens , serves to enlarge the shadow object , located on the revolver .d . Ocular lens , serves to enlarge the shadow of the object , located at the top of the tube .

Scientific Work

Scientific Work If someone wants to know something by observation , would not work well if the observations made without going through the steps or planned and systematic method to obtain evidence of the biotic and abiotic . Biotic is a living part of nature , while abiotic are natural objects that are dead . Step or the most appropriate method used in the observation that the scientific method .
The scientific method is a tool to solve problems , find out the cause so that the conclusions that can be reasonable and credible . To that end , the scientific method and scientific attitude person uses in making observations . The steps of the scientific method , as follows :
1 . Discovering the problem and formulate the problem .2 . Collecting information to solve the problem .3 . Develop assumptions or hypotheses for obtaining temporary answer .4 . Testing allegations by conducting experiments or experiments .5 . Attractive conclusions .6 . Testing conclusions by repeating the experiment .
Scientific attitude must be owned by an observer , among others , as follows :
1 . Loved truth this attitude encourages someone to be honest and objective .2 . Not ancient thought not think prejudice is not good and does not make sense .3 . Characteristically tolerant of other people's knowledge is not absolutely perfect , then respect the opinions of others can be used to repair , equip , improve knowledge and not force others .4 . Ductile not desperate and always trying to find the truth but often do not gain anything .5 . Thorough Thorough and careful in doing something and be careful in drawing conclusions and opinion.6 . Want to know curiosity is the starting point of knowledge to pushed to want to know more of doing things 7 . Optimistic Always optimistic as familiar with the trials or experiments . In the experiment therethe factors that influence the experiment . These factors were named variables . There are four kinds of variables , namely :1 . Manipulative independent variable or variables independent variable was deliberately different factors or altered .2 . Dependent variable or response variable The dependent variable is the variable obtained by other variables .3 . Variable controls are control variables that must be controlled .4 . Variables confounding variables are confounding factors that may affect the results of the experiment , but it can not be predicted in advance . From the observations made , the result is called data . There are two ( 2 ) kinds of data , namely :
1 . Qualitative data is data is not presented in the form of numbers .2 . Quantitative data is data that is presented in the form of numbers . The results and conclusions from experiments or observations reported
in a journal called scientific journals . Scientific journal is a magazine that contains articles or posts which contains research reports . Diverse forms of scientific journals , there are published weekly , monthly orthree months. With the development of science and technology scientific journals can be viewed over the internet .

Factors that affect chemical reactions

Factors that affect chemical reactions Chemical reactions can take place quickly, it can also be slow. There are several factors that affect the rate of reaction, among others:

1. Factors Particle Size

Collisions between reactants can result in a chemical reaction to a substance. The more collisions occur, the faster the reaction takes place. Particle size affects the speed of the reaction of a substance.

2. Factor Temperature

How is the effect of temperature on reaction rate? The higher the reaction temperature, the faster the reaction takes place. If the temperature is raised to cause the movement of reactant particles faster. The faster the movement of the particles causing the collision between reactants increased, so that the reaction becomes rapid.

Characteristics of Chemical Reactions

Characteristic Chemical Reactions Chemical reactions that occur result in some changes , among others :
1 . Characteristic Chemical Reaction Formation Deposition
Try to observe the bottom of the pot used to boil water , is there anything that sticks to the pan ? The substance is a carbonate compound that is formed when water containing lime in heat .
2 . Characteristics Produce Gas Chemical Reaction
Have you seen the workers were welding the weld metal ? Carbide is mixed with water , produces acetylene will react . Acetylene used for splicing metal by
welding . In the food industry , while making the cake batter baking soda added . At the time of the heated cookie dough , baking soda produces carbon dioxide gas decomposes . This causes the gas to inflate the cake batter . What happens , if the cookie dough is not coupled with baking soda ?
3 . Characteristics of Temperature Changes in Chemical Reactions
What can you observe , when bonfires were lit ? Combustion reaction is an exothermic reaction . Exothermic reaction is a chemical reaction that produces energy . The energy produced can be either hot or heat . In the event of a chemical reaction of photosynthesis requires energy . The chemical reaction is called an endothermic reaction requires energy .

Various chemical reactions

Various chemical reactions in order to facilitate the conduct of chemical reactions , chemical reactions are then grouped by similarity owned . One classification system based on the way the atoms rearrange in chemical reactions , among others :
1 . Chemical reactions Merger
In reaction to the merger of two or more substances incorporated to form other substances . The general formula coupling reaction as follows :
A + B → AB
example
The reaction between hydrogen with oxygen to form water is a coupling reaction .
2H2 ( g ) + O2 ( g ) → 2H2O ( )

2 . Chemical decomposition reactions
Decomposition reaction is the opposite reaction than the coupling reaction . In this reaction a split or decomposed substance into two or more simpler substances . Most of these reactions require energy in the form of heat , light , and electricity . The general formula decomposition reaction as follows :
AB → A + B
example
Decomposition reaction of water by electricity generating hydrogen and oxygen . electricity
2H2O ( ) → 2H2 ( g ) + O2 ( g )
3 . Chemical Reaction Replacement
Single replacement reaction occurs , when one element replaces another element in a compound . To complete the replacement of the equation , there are two equations , namely :
a. At issue , A replaces B as follows :
A + BC → B + AC
b . At issue , the D replaces C as follows :
D + C + BC → BD
example
A copper wire is inserted into a solution of silver nitrate . Copper is more active than silver , copper replaces the silver to form a solution of copper ( II ) nitrate is blue . The reaction between copper with silver nitrate , as follows :
Cu ( s ) + 2AgNO3 (aq ) → 2AG ( s ) + Cu ( NO3 ) 2 ( aq)

Some things to consider in the equation of Chemistry

Some things to consider in the equation , namely :
1 . Coefficient
Numbers are on the left formula reactants and reaction products are called coefficients . Each coefficient in the equation represents the number of units of each substance in the reaction
2 . Steps Balance Chemical Reactions
Equalizing the reaction equation can be done with the following steps :
a. Set the coefficient of one of the substances , which usually has the most complex formula equal to one , while other substances are given coefficients while the form of letters .
b . First balance the elements directly related to the coefficients of the given substance .
c . Balance the other elements .
example
The reaction of methane ( CH4 ) with oxygen gas to form carbon dioxide gas and water vapor .
Step 1 :
Write down the formula of the reactants and the reaction proceeds as follows :
CH4 ( g ) + O2 ( g ) → CO2 ( g ) + H2O ( g )
Step 2 : Equalization
1 . Specify coefficient of CH4 = 1 , while the other with the letter CH4 ( g ) + AO2 ( g ) → bCO2 ( g ) + CH 2 O ( g )
2 . Balance the atoms C and H. Note the number of C atoms on the left = 1 ; mean number of C atoms on the right = b = 1 . Notice the number of H atoms on the left = 4 ; mean number of H atoms on the right = 2c , meaning 2c = 4 , or c = 2
3 . Balance the O atoms , the number of O atoms on the left = 2a . On the right side = 2 + 2 = 4 , then 2a = 4 or a = 2 . Thus obtained the following equation : CH4 ( g ) + 2O2 ( g ) → CO2 ( g ) + 2H2O ( g )

Chemical reaction equation

Equation describe chemical reactions which consisted of reagent chemical formula and reaction products with coefficients respectively . In a chemical reaction , one or more substances may be transformed into a new kind of substance . Substances react called reagent ( reactant ) , while the new substances produced are called the reaction product ( product ) . John Dalton argued that , the type and number of atoms involved in the reaction has not changed , but the chemical bond between the two substances change . The changes can be explained by using the chemical formulas of substances involved in the reaction equation is called . For example , the reaction between hydrogen gas with oxygen gas to form water can be explained as follows :
2H2 ( g ) + O2 ( g ) → 2H2O ( )
Symbols used in the equation , such as:
→ produce+ plus( s ) solid ( solids )( g ) gas( ) Liquid ( fluid )( Aq) aquous ( dissolved in water )
Numbers that precede the chemical formula of the substance in the equation is called the coefficient of the reaction . In the example above can be explained that the coefficient of hydrogen is 2 , the coefficient of oxygen is 1 , and the coefficient of water is 2 . Posting equation can be done in two steps
a. Write down the formula of reactants and products , complete with a description of his form .
b . Equivalency , which gives the coefficients corresponding to the same number of atoms of each element on both formulas .

separation of the mixture

Have you ever wondered , if the oil that is in liquid oil wells already ? Why cooking oil mixed with water when heated will cause sparks ? Well , consider the following explanation of this ! Each substance is composed of particles that are very small . The existence of particles can be demonstrated , for example one tablespoon of salt dissolved in a glass of water . What can you feel when the solution is worth trying ? Not taste salty ? How can we obtain the salt that has been dissolved in water ? Try to heat the salt solution to boiling , so that all the water evaporates . You will get back the salt . This suggests that the separation of the mixture can be made ​​based on the difference in boiling point between the constituent particles . Separation of the mixture can be done in various ways , among others :
1 . Separation of the mixture by means of filtration ( filtration )
Have you ever seen a construction worker who was doing the separation between the sand with gravel ? Do you know why after shredded coconut should knead while adding water ? Separation of sand with gravel and water to the grated coconut separation aims to separate substances that are mixed in the mixture . Particles that have a smaller size will escape intact, large sieve will be captured on the filter. Why well water looks clear even though it was raining ? Natural events to earth rain will flow to the lower surface of the earth by bringing other substances .
The water seeped into the soil through tiny cracks , and suffered filtering by the soil layer , thus resulting clear water sources . Separation of mixtures of laboratory operations can be performed using filter paper . Selection of filter size adjusted to the size of the substances to be separated . Separation of the mixture by looking at the difference in solubility can also be done by filtration ( filtration ) . Example , we want to separate a mixture of salt and sand . Step we take is to provide water to the mixture . Water is a solvent for substances that have properties dissolved . In this case the salt can be dissolved by water , while sand . Through a sand filtration process will be left behind , while the salt water passes from the filter . Substances are stuck and left in the filter paper is called the residue . Fluid can escape from the filter paper is called the filtrate .
2 . Separation of the mixture by means of Distillation ( distillation )
Refining or distillation is the process of separating a liquid mixture based on differences in boiling point substances . The process of separation of the mixture by means of distillation carried out by two processes , namely evaporation and condensation . Examples of the separation of the mixture by means of distillation , such as: obtaining gasoline from a mixture of water and gasoline , obtaining pure water from a mixture of water that has been contaminated with dissolved solids in it , obtaining water from a mixture of water and salt .
3 . Separation of the mixture by means of crystallization
Solids can not be separated from the solution by means of filtered . Solid substances , such as sugar and salt are dissolved in water can be separated from the solution by evaporation and occurs
crystallization . Farmers get salt salt by evaporating sea water . How do farmers get salt salt from sea water ? Sea water flowed into the ponds to be made off the coast . The flow of sea water can occur because one natural events , namely the tide is affected by the moon's gravity . After the sea water trapped in ponds , further evaporation process occurs with the help of sunlight . The water contained in the sea water will evaporate , thus forming salt crystals .

4 . Separation of the mixture by means of Sublimation
Separation of the mixture by sublimation performed on substances that can sublimate . Sublimation is the change of a substance from the solid state to gas or vice versa . Substances that can sublimate , among others : camphor , iodine , caffeine and others.
5 . Separation of the mixture by means of Chromatography
Mixture separation process based on differences in velocity between the particles propagate substances mixed in a medium called chromatography . Activities you can do , eg how to separate a mixture of black ? Black ink is a mixture of several colors . Black separation into its constituent colors can be done by chromatography . understanding mix

physical and chemical changes in substances

1 . Changes in physical substance
Physical changes are changes to the substance does not produce new types of substances . For example , rice is ground into flour . Rice is ground into flour , just show the shape and size of the change , but the molecular nature of the substance remains the same rice and flour . Events change states of matter , such as: evaporate , condense , melt , freeze , sublimate , crystallizing a physical change . There are several characteristics of the physical changes , ie : not formed a new kind of substance , a substance that can turn back into shape , just followed the changing nature of physics alone . Changes in physical properties that appear are the shape , size , and color change .
2 . Changes in chemical substances
A chemical change is a change in a substance that produces a new type . Have you ever burn paper ? What can you see after the paper went up in flames ? There ash obtained as a result of the combustion process . Paper before the fire have different properties to the paper after burned . Examples of chemical changes , such as: rice rot , stale milk , vegetables became stale , rotting eggs , salted eggs , rusty iron , and others . There are some characteristics of chemical changes of a substance , ie a substance to form a new kind , a substance that can not be changed back to its original form , accompanied by changes in the chemical properties through chemical reactions . During a chemical change , substances before the reaction mass equal to the mass of a substance after the reaction .

Chemical properties of a substance

Chemical properties of a substance is a characteristic of a substance that is associated with the formation of new types of substances . Note metals that are around you , whether all can react with oxygen ? Iron includes substances that easily react with oxygen , which would cause the iron to rust . Here are some examples of chemical properties owned by an object , namely :
a. The chemical properties of flammable substances
Have you ever noticed , why refueling station there is a ban on " NO SMOKING " ? This warning is intended to remind the consumer that , gasoline including flammable substances . By knowing the properties of the materials are flammable, we will be able to use it safely .
b . Chemical properties of substances and sour rot
As a result of chemical reactions occur in a food or beverage , food and drink can lead to the rot and turn into a sour taste . For example , rice that is left for days to react with the air becomes stale , the milk is turned into a sour taste .
c . Chemical properties of substances Rustic
The reaction between metal and oxygen can lead to the rusty object . Metals , such as iron and zinc is easily corroded . There are objects that can not rust , such as plastic and glass . Rusting is a chemical property , because the reaction occurs that produces a new type .
d . The chemical properties of substances explode Easy
Interaction with oxygen in natural substances that have no explosive properties , such as : magnesium , uranium and sodium .
e . Toxic chemical properties of substances
There are some substances that have toxic chemical properties , such as: insecticides , pesticides , fungicides , herbicides and rodenticides . The toxic substances used by humans to eradicate pests , both insects and mice . understanding of substance

Physical properties of substances

Substances Substances have properties characteristic of each . Copper wire you can bend easily , while the hard iron bar bent . Characteristic of a substance that can be observed without changing the substance of the constituent materials , called physical properties . Physical properties of an object , such as:
a. Being physical properties of substances
Three kinds of states of matter that we know are : solid , liquid and gas . The substance can be transformed from one form to another form . Some events change as we know , namely : evaporate , condense , melt , freeze , meyublim , and crystallized . Substance has a boiling point and melting point is different for each type of substance . The boiling point of water at normal atmospheric pressure ( 76 cmHg ) is 1000C , while gasoline approximately 800C .
Colour physics b.sifat
Each object has a different color . Color is a physical property that you can observe directly . The color of an object is owned by distinctive characteristics that distinguish between one substance with another substance . For example , milk white , carbon black , pale gray nails and others.
c . physical properties of solubility
Water is a solvent for the solutes . Not all substances can be dissolved in a solvent . For example , salt is soluble in water , but coffee is not water soluble . The solubility of a substance in a specific solvent is a physical property .

d . physical properties of electrical conductivity
Metal objects in general can conduct electricity . Objects that can conduct electricity well are called conductors , while objects that can not conduct electricity are called insulators . The electrical conductivity of a substance can be observed from the symptoms it causes. For example , copper is connected with a voltage source and a lamp . As a result of what you can look is to turn on the lights . Electrical conductivity is a physical property .
e . physical properties of Magnetism
Based on the magnetic properties , objects are classified into two objects magnetic and non- magnetic objects . Magnetic objects are objects that can be drawn by a powerful magnet , while the non- magnetic objects are objects that can not be pulled by a magnet . For example , there is a mixture of iron filings and sand . Separation of this mixture can not be done by filtering or sieving . An easier way is to bring a magnet to the mixture . Including magnetic iron powder material , it will be attracted to the magnet . Differences physics as an object of interest in a magnet can be used to separate substances in a mixture . Try to collect some other information , about the physical properties of an object !

Benefits of Heat in Everyday Life

Benefits of Heat in Everyday Life In everyday life you have encountered many household appliances which works using the principle of heat transfer concepts , eg pressure cooker ( pressure cooker ) , irons , tool refining , and refrigeration . Here are some examples of the application of heat transfer is radiation in everyday life .
a. On a hot day , people prefer to wear bright clothes of the dark clothes . It aims to reduce heat absorption b . Paint made ​​shiny car or motorcycle to reduce heat absorption .c . Wearing a thick jacket or snuggled under a thick blanket of cold air when your body feels comfortable . Including the air a good insulator . Some insulating material composed of many tiny air pockets encased . The bag prevents heat transfer by convection . So do you know why in a blanket filled with tiny hairs or fibers that trap air ? This is done to prevent the possibility of heat loss .d . Wall thermos flasks coated silver . It aims to prevent heat loss is radiation . Vacuum between the glass walls of the flask to prevent heat transfer by convection .

Radiation heat transfer in or radiance

Radiation is the emission of radiation or heat transfer without going through an intermediary substance. When the first fire at Scout activities at your school, what did you feel when you're around a campfire flame? You will feel the warmth of a campfire from a distance apart. How hot campfire can get to your body? Heat received from a campfire flame caused by the energy beam.

The tools used to detect heat radiation or radiant heat energy called termoskop. Termoskop consists of two pieces of glass balls connected by a U pipe filled with water colored alcohol. From the results of observations made can be concluded that:

1) The surface of a black body, dull, rough and a transmitter and a good heat absorber.

2) The surface of the white stuff, shiny and smooth is a transmitter and a poor absorber of heat

Convection is heat transfer or flow

Convection Convection is the movement or flow of heat in a substance that is accompanied by displacement of the particles of the substance. Convection occurs because of differences in the density of the substance . You can understand convection events , among others :
1 ) In the liquid due to differences in the density of a substance , eg water heating systems , hot water flow system .
2 ) In a gas substance due to differences in air pressure , such as the sea breeze and land breeze , air ventilation system , to get the cooler air in the room mounted air conditioner or fan , and factory chimneys .
The sea breeze and onshore wind are examples of natural events involving convection currents in the gas substances . Do you know how the sea breeze and onshore wind ? During the day the land heat faster than the oceans . This resulted in a hot air will rise and the land is filled by cold air from the sea surface , resulting in the movement of air from the ocean toward land commonly called the sea breeze . Sea breezes occur during the day , commonly used by traditional fishermen to return to the mainland . How onshore winds occur ?
At night the land is colder than the ocean faster . This resulted in hot air at sea level will rise and the place is filled by cold air from the mainland , resulting in the movement of air from land to the sea which is called onshore wind . Onshore winds occur at night , usually used by traditional fishermen to go to sea for fishing .

Heat Transfer by conduction / conduction

Heat Transfer Heat can move from one place to another . How do I heat it changed ? Heat can be transferred in three ways , namely conduction or conduction , convection , or flow , and
radiation or emission .
Conduction is the transfer of heat through a substance without displacement of the particles of the substance by heat conductivity , objects can be divided into two , namely :
1 ) Conductor
Conductors are substances that have good heat conductivity . Example : iron , steel , copper , aluminum , etc.
2 ) Isolator
Insulators are substances that have a poor conductor of heat . Example : wood , plastic , paper , glass , water , etc.
In everyday life , you can encounter housewares principle works utilizing the concept of heat transfer by conduction , such as: electric irons , solder . Why are household appliances such as irons , solder , pots , pans hold of materials are insulators ? It aims to prevent heat conduction to not come down to us .

Dissolve the substance remains Requires Temperature Heat

Dissolve the substance remains Requires Temperature Heat At melted liquid is transformed from solid to liquid requires heat . At normal air pressure ice transformed from solid to liquid at a temperature of 00C . Heat energy required to raise the temperature is not used , but to change the states of matter from solid to liquid . The temperature at the time of the solids melt is called the melting point . If the outside air pressure change , the melting point of substances will also undergo changes . It can be shown that the air pressure of 76 cmHg ice will melt at temperatures below 00C .
Melting point of a substance can be changed by means of : pressure plus the melting point down , the pressure is reduced then the melting point rises, and then add the impurity substance melting point down . How you can explain how to make ice cream ? Why is the ice cream maker is mixing salt with ice ? Salt mixed with ice cubes to lower the temperature of the ice to -20 0C .
These events can be used to cool the water to ice in making ice cream . fall
salt lowers the temperature due to the melting point of ice . Some everyday appliances that utilize the properties of heat , such as: rice cooker , pressure cooker , freezer, water distillation equipment , autoclaves ( bacteria -killing ) . To change the solid state to a liquid at the melting point of heat energy required . The amount of heat energy needed to change 1 kg of a substance from the solid state to a liquid at its boiling point is called the heat of melting . Mathematically it can be written :

 
Q = m x L
information
Q = heat energy required ( J )
m = mass of substance ( kg )
L = heat of melting ( J / kg )
When melting occurs substance requires heat , while the freezing liquid releases heat until it turns into a solid . The amount of heat that is released to change 1 kg of a substance from liquid to solid form in the so-called heat frozen freezing point . Freezing point is the temperature at which liquid water freezes . Experiments conducted by scientists produces a statement that :
Melting Heat = heat frozen

Factors Affecting Evaporation

Factors Affecting Evaporation
There are several volatile substances , among others : spirits , gasoline , alcohol , etc. . Have you seen why a hot beverage is poured in the cup ? Have you fed your sister hot food , why should blow first? Why should wash wet clothes dried in the sun ? Now follow the following explanation ! .
Understanding Evaporation is a moving event release molecules from the surface of the liquid . Some way speed up evaporation , namely :
a. heat
When finished washing some clothes , try jemurlah one in the shade and some in the hot sun . Which dry faster ? In drying you do , the clothes in the sun to dry. This suggests that the water contained in the clothes evaporates faster .
b . Expanding the liquid surface
Pour hot coffee portion you made on plates . Wait a minute , then drink . Just compare , which one is faster cold water or a cup of coffee in the cup ? You will get the coffee in the cup of water faster than cold water in a cup of coffee . This shows that the evaporation of water in the cup of coffee that has a wider surface will be faster than evaporation in the glass .
c . Blowing air over the surface of a liquid
When you feed your sister with hot food , why should blow first? Hot foods whose surface is blown cold rather fast . This is because the food is blown faster evaporation so cool .
d . reduce pressure
By reducing the air pressure on the surface of a substance , resulting in the distance between air molecules becomes large . This results in the molecules on the surface of the liquid will move on to the air in it so speed up the evaporation process .
Some events evaporation , among others :
1 ) Boil water 100 0C .
2 ) Drying wet clothes to be dried .
3 ) Evaporation freon gas in the refrigerator .
4 ) Alcohol or rubbing alcohol hand dripped on the skin can evaporate .

Understanding heat and heat formula

Heat is a form of energy that can naturally move from a high temperature object to the lower temperature when in contact . Heat can also move from a low temperature to a higher temperature when the engine is assisted by means of cooling . So that you may better understand the heat .
From some of the above conclusions can be drawn a statement that the amount of heat required to raise the temperature as follows :
The amount of heat ( Q ) required by an object is proportional to the mass of the object( m ) , depending on the specific heat ( c ) , and is proportional to the temperature rise ( Δt ) . Mathematically it can be written :
Q = m x c x Δt
information
Q = heat required or released ( J )
m = mass of object ( kg )
c = specific heat of objects ( J/kg0C )
Δt = temperature rise ( 0C )
Δ = delta
According to the SI unit of heat is joule ( J ) . There is a unit of heat commonly used in everyday life , such as kilocalories , calories . One can be defined many calories of heat are required every 1 gram of water , so that the temperature rise of 10C . While a defined number of kilocalories of heat required to raise 1 kg of water , so that the temperature rise of 10C . There is equality between the unit joule calorie Dangan unit commonly known as heat between mechanical .
1 calorie = 4.2 joules1 kilocalorie = 4,200 joules1 joule = 0.24 calories
Specific heat of a substance is the amount of heat that is required by 1 kg of a substance so that the temperature rise of 10C . Mathematically the specific heat of a substance can be written :
c = Q / mxΔt
While the heat capacity is the amount of heat that is required by an object so that the temperature rise of 10C . Mathematically, the heat capacity can be written :
C = m x c
because :
Q = m x c x Δt then ,Q = C x Δt
information
Q = heat required or released ( J )
C = heat capacity of objects ( J/0C )
Δt = temperature rise ( 0C )
Δ = delta