· The word material is related to things that are around us.
· Matter is any abject around us that occupy space and has mass
· Matter can found in around us in three state Solid , liquid and Gas
· In solid state, particles of matter are tightly packed and having no gap between them. Due to this reason Solid have definite shape and volume.
· In liquid state , particles of matter are loosely packed together have some space between then .due to this reason liquid have fix volume but no fix shape .
· In Gas particles of matter are far from each other due to this gas have no fix volume and shape.
· Both liquid and gas are called fluids as they can flow due to weak force of molecular attraction between particles.
· We have large numbers of material around us and we need to know about their properties. To make study of the nature of different substance easy we have to divide it into group.
· Shorting of material into group on the basis of similarity of different substance is called Classification.
· Material around us classified on the basis of their properties:
(a) Appearance or luster
(b) Hardness or softness
(f) Conductivity of heat and light
Q. What is luster?
Ans: Materials around us have a particular type of shine called Luster like gold, silver, aluminum etc
Q. Some metal can hammered into thin sheet without breaking into pieces. Name this property of metals?
Q. Some metal drawn into thin wire. Name this property of metals?
Q. Name material used to make chalk?
Ans: Calcium carbonate
Q. Why do houses have cement floor?
Ans: Houses have cement floor because it can polished to make attractive.
Q. Define soluble and insoluble substance?
Ans: Material that mixed with water is called soluble e.g. acid, base, milk, lemon juice, sugar and alcohol. Material that do not mixed with water is called insoluble like oil, sand, alum etc
Q. what will happen if you drop piece of chalk and sponge in to glass of water?
Ans: Chalk and sponge absorb water due to gap between their particles.
Q. Which material you prefer to use for furniture?
Ans: Wood and Metal as they can polished and hard to break.
Q. Classify material on the basis of conductivity?
Ans: Materials have property to conduct electricity through them. This property is called conductivity. On the basis of that it can be divided into Good conductor and bad conductor.
A substance which conducts electricity is called good conductor like silver, copper, aluminum.
Q. Name the best conductor metal?
Ans: Silver is best conductor.
Q. Name a non metal that conduct current?
Ans: Graphite is only non metal that conduct electricity.
Q. What is the name of material that can scratch easily?
Q. Name hardest and softest substance
Ans: Diamond and talcum powder
Q. What does cold drink contains.
Ans: carbon dioxide gas, sugar and flavored syrup.
Q.Why axe head is made up of iron?
Ans: Because iron is cheap, hard and malleable.
Q. Defines: Solute, solvent and solution?
Ans: Solution: The mixture of two or more substance is called solution. Solute: A substance that is being dissolved is called Solute. Solvent: The substance in which solute dissolve.
Q. Why ice floats on water?
Ans: The density of ice is lower than water so, Ice floats on water.
Q.What is transparency?
Ans: The property of substance to allow light to pass through is called transparency.
Q. What is Opaque object?
Object that do not allow light to pass is called opaque like wood, metals etc.
Object that allow light to pass partially is called Translucent. Glass, water, Oil paper etc.
Q. Why handle of utensils made up of Plastic or wood?
Ans: because Plastic or wood
Q. What kind of substance do we see around us?
Ans: we have two types of substance like man Plastic or wood made and natural.
Q. Why do some substance sink or others floats to the beaker field with water?
Ans: Some substances do not dissolve in water so they float unless sink.
Q. Why we can smell something e.g. perfume?
Ans: we can smell something e.g. perfume because smell the liquid floats in the air when evaporated.