Properties of Materials
We use variety of objects in our day to day lives. Objects are made up of different materials.   An object can be made from more than one material Example: Cake, Soaps Different objects can be made from the same material Example: Table, Chair, and Door are made from wood. An object can be made from different materials Example: Bottles from glass, Plastic, metals. Importance of grouping Grouping materials in groups makes it convenient for study. Objects are grouped on the basis of their shapes, the materials they are made up of, and the properties of these materials. Materials can be grouped on the basis of similarities or differences in their properties. Grouping of objects on the basis of common properties Objects are grouped on the basis of properties like lustre, hard/softness, transparency, solubility, floatation, attraction towards magnet, conduction of heat and conduction of electricity. Property - Lustre:  Materials can be grouped as lustrous and non-lustrous on the basis of lustre/shine possessed by them. Lustrous materials are those that have a shine on them. Due to this property metals are widely used for making jewellery. Example: Gold, silver and most metals are lustrous in nature. Non-lustrous materials are dull in appearance. Example: Wood, Plastic, etc. Property - Hard/Softness Materials that can be compressed or scratched easily are called soft materials. Example:  Cotton, Sponge. Some materials that are difficult to compress are called hard. Example: Iron and most of the other metals. Property - Transparency Materials can be classified as transparent, opaque and translucent on the basis of transmittance of light by them.   Transparent Materials Transparent materials allow light to pass through them completely. One can see through such materials Example: Glass, water, Air and Some plastics   Opaque Materials Opaque materials do not allow light to pass through them. You cannot see through them. Example: Wood, cardboard and metals.   Translucent Materials Translucent materials allow light to pass through them only partially. They are partially transparent and partially opaque. Example: Butter paper, Frosted glass. Property- state Everything in this universe is made up of matter. Matter exists in 3 states - Solid state, liquid state and gaseous state. Solid state All solid substances are said to have solid state. Properties of solid state      •  Solids have definite shapes, volumes and are not compressible.      •  The particles are closely packed and they cannot flow. Liquid state All liquid substances are said to have liquid state. Properties of liquid state      •  Liquids do not have definite shapes; they take the shape of the container and have definite volume.      •  The particles of liquids are loosely packed than the particles in solids      •  They can be compressed to a small extent.  Gaseous state All gaseous substances are said to have gaseous state. Properties of gaseous state      •  Gases have no definite shape or volume      •  Particles of a gas are very loosely packed      •  Gases are highly compressible. Property - Soluble or Insoluble Substances that completely dissolve in water are said to be soluble in water. Example: Lemon juice, vinegar, sugar, salt are completely soluble in water and form a single layer with water. Materials (solids or liquids) that form distinct layers with water are said to be insoluble in water. Example: Substances like sand and sawdust do not dissolve in water even if you stir them very well. They are said to be insoluble in water. Lemon juice, vinegar are completely soluble in water and form a single layer with water whereas mustard oil and kerosene will not dissolve in water, but will form distinct layers. Liquids that are soluble in water and form single layer with water are said to be miscible in water. Whereas liquids that are insoluble in water and form distinct layers are said to be immiscible in water. Some gases can dissolve in water as well. For example, oxygen dissolved in water is useful for plants and animals that live underwater.  Property - Float or Sink Materials that are insoluble in water either float on the surface or sink in water. Light materials float in water. Example: Paper, Plastic boll etc.  Heavy materials sink in water. Example: Metals, stones etc. Attraction towards a magnet Substances that are attracted to a magnet are called magnetic substances. Example:  Iron, Nickel. Conduction of heat Materials that allow the heat to pass through them are called good conductors of heat. Example: Generally metals are good conductors of heat. Materials that do not allow the heat to pass through them are called bad conductors of heat. Example:Plastic, air. Conduction of Electricity Materials that conduct electricity are called conductors. Example: Generally metals are good conductors of electricity. Materials that do not conduct electricity are called insulators or bad conductors of electricity. Example: Plastic, Wood, air.

#### Summary

We use variety of objects in our day to day lives. Objects are made up of different materials.   An object can be made from more than one material Example: Cake, Soaps Different objects can be made from the same material Example: Table, Chair, and Door are made from wood. An object can be made from different materials Example: Bottles from glass, Plastic, metals. Importance of grouping Grouping materials in groups makes it convenient for study. Objects are grouped on the basis of their shapes, the materials they are made up of, and the properties of these materials. Materials can be grouped on the basis of similarities or differences in their properties. Grouping of objects on the basis of common properties Objects are grouped on the basis of properties like lustre, hard/softness, transparency, solubility, floatation, attraction towards magnet, conduction of heat and conduction of electricity. Property - Lustre:  Materials can be grouped as lustrous and non-lustrous on the basis of lustre/shine possessed by them. Lustrous materials are those that have a shine on them. Due to this property metals are widely used for making jewellery. Example: Gold, silver and most metals are lustrous in nature. Non-lustrous materials are dull in appearance. Example: Wood, Plastic, etc. Property - Hard/Softness Materials that can be compressed or scratched easily are called soft materials. Example:  Cotton, Sponge. Some materials that are difficult to compress are called hard. Example: Iron and most of the other metals. Property - Transparency Materials can be classified as transparent, opaque and translucent on the basis of transmittance of light by them.   Transparent Materials Transparent materials allow light to pass through them completely. One can see through such materials Example: Glass, water, Air and Some plastics   Opaque Materials Opaque materials do not allow light to pass through them. You cannot see through them. Example: Wood, cardboard and metals.   Translucent Materials Translucent materials allow light to pass through them only partially. They are partially transparent and partially opaque. Example: Butter paper, Frosted glass. Property- state Everything in this universe is made up of matter. Matter exists in 3 states - Solid state, liquid state and gaseous state. Solid state All solid substances are said to have solid state. Properties of solid state      •  Solids have definite shapes, volumes and are not compressible.      •  The particles are closely packed and they cannot flow. Liquid state All liquid substances are said to have liquid state. Properties of liquid state      •  Liquids do not have definite shapes; they take the shape of the container and have definite volume.      •  The particles of liquids are loosely packed than the particles in solids      •  They can be compressed to a small extent.  Gaseous state All gaseous substances are said to have gaseous state. Properties of gaseous state      •  Gases have no definite shape or volume      •  Particles of a gas are very loosely packed      •  Gases are highly compressible. Property - Soluble or Insoluble Substances that completely dissolve in water are said to be soluble in water. Example: Lemon juice, vinegar, sugar, salt are completely soluble in water and form a single layer with water. Materials (solids or liquids) that form distinct layers with water are said to be insoluble in water. Example: Substances like sand and sawdust do not dissolve in water even if you stir them very well. They are said to be insoluble in water. Lemon juice, vinegar are completely soluble in water and form a single layer with water whereas mustard oil and kerosene will not dissolve in water, but will form distinct layers. Liquids that are soluble in water and form single layer with water are said to be miscible in water. Whereas liquids that are insoluble in water and form distinct layers are said to be immiscible in water. Some gases can dissolve in water as well. For example, oxygen dissolved in water is useful for plants and animals that live underwater.  Property - Float or Sink Materials that are insoluble in water either float on the surface or sink in water. Light materials float in water. Example: Paper, Plastic boll etc.  Heavy materials sink in water. Example: Metals, stones etc. Attraction towards a magnet Substances that are attracted to a magnet are called magnetic substances. Example:  Iron, Nickel. Conduction of heat Materials that allow the heat to pass through them are called good conductors of heat. Example: Generally metals are good conductors of heat. Materials that do not allow the heat to pass through them are called bad conductors of heat. Example:Plastic, air. Conduction of Electricity Materials that conduct electricity are called conductors. Example: Generally metals are good conductors of electricity. Materials that do not conduct electricity are called insulators or bad conductors of electricity. Example: Plastic, Wood, air.

#### Activities

Activity 1 Sciencekids.co has created a wonderful interactive simulation on Properties of Materials. Students learn different properties of materials on their own by testing the properties of materials in a tester. This activity is very useful for younger students. Students can also learn more about grouping of objects. Go To Activity Activity 2 Librosvivos.net has created an interactive animation on “Properties of Materials”. This is a quiz based activity. Students has to mark incorrect answer they will not allow to cross the brick barrier. If they mark correct answer they will allow to cross the brick barrier. This is a funny activity which imparts knowledge along with fun. Go To Activity Activity 3 Pbs.org has build an interactive educational simulation on "Properties of Materials". Students learn strengths of different materials on their own by testing them. Student can also lean more about applications of different materials. Go To Activity