The Basics of Physics-Friction

Friction occurs when two bodies slide over each other.Friction can be defined as the resistance to motion experienced when two surfaces in contact move with respect to each other.
Whenever two bodies slide over each other,each exerts a force which opposes movement.We can see that as it becomes harder to move the objects.Rough and coarse surfaces offer more friction than smooth and polished surfaces.We can walk easier on rougher surfaces than on smoother surfaces due to friction.Friction can also be produced by air and water which can oppose the motion of vehicles.

Basics of Physics-Force

A force is a push or pull acting on an object.A common example of force is pushing or pulling someone,kicking a football,swinging a bat,etc.
Force can do many things to an object

• It can stop or slow down a moving object
• It can move a still object
• It can change the shape or size of an object
• It can change the speed of a moving object
• It can change the direction of a moving object

 

Chemistry Fun Activity 1

Hello!As we discussed earlier,graphite is a non-metal which is a good conductor of electricity.Now we will use this property to make a circuit with graphite as a medium.Take a look at the instructions to make your circuit.


Materials you need:
Some wire,A bulb,Battery,2 pencils sharpened at both ends,some cello tape and scissors.

Method

1. Take 2  pieces of wire and cut them into two halves each so that you have four reasonably long pieces of wire
2. Connect two pieces of wire two the Battery and the other two pieces to the bulb.
3. Now you will have two separate halves of the circuit,one with the bulb and one with the battery.
4. Now connect the two halves of the circuit with the pencils MAKING SURE THAT THE WIRE TOUCHES THE LEAD OF THE PENCIL.
5. Now your circuit is ready.

Basics of Chemistry-Physical and Chemical changes

Physical Change
Physical changes are changes that do not produce new substances.Most of the physical changes are reversible.However,some physical changes like tearing of paper are not reversible.Other examples of Physical changes are mixing salt with water,freezing of water,breaking of glass.

Chemical Change
In a chemical change,a new substance is formed.Chemical changes are irreversible.Some examples of Chemical changes are growing up,cooking of food,burning of a substance,etc.

  

 

Basics of Chemistry-Compounds and Mixtures

Compounds and mixtures are two more important parts of chemistry. 

Mixtures
Mixtures are a combination of two or more substances that are mixed simply.This is a physical change and the original substances can be obtained from the mixture.A common example of a mixture is Salt water.Sand mixed with water is also a mixture.

Compounds
Compounds and mixtures are almost same.But in a compound,two or more substances are chemically combined.This is a chemical and irreversible change and the original substances cannot be obtained.A common example of a compound is water.

 

  
 

The Basics of Chemistry-Non Metals

Any element which is not a good conductor of heat and electricity is called a non-metal.The exceptions are Diamond which is a good conductor of heat and Graphite which is a good conductor of electricity.Some examples of non-metals are Oxygen,Hydrogen,Nitrogen,Carbon,Sulphur,Bromine,etc.We saw in the last post about a few characteristics of metals.Now let us see if they apply to non metals.Before you continue reading,make sure you read my last post on metals.

Physical form
Nearly all non-metals are solids or gases at room temperature with the exception of Bromine,which is a brown coloured liquid at room temperature.

Lustre
Unlike metals,most non-metals are not lustrous with the exception of graphite and iodine which do show some lustre.

Colour
Some non-metals show colour while some are colourless.For example,Oxygen and Nitrogen are colourless gases while Sulphur is a yellow element.

Hardness
Non-metals are usually soft.The exception is Diamond which is the hardest substance known.

Malleability
Non-metals are brittle and cannot be beaten into sheets or foils.

Ductility
Non-metals are brittle and cannot be beaten into sheets or foils.

Thermal Conductivity
Most non-metals are not good conductors of heat.The exception is diamond.

Electrical Conductivity
Most non-metals are not good conductors of electricity with the exception of graphite.Graphite is a good conductor of electricity.

Sonority
Non-metals are brittle and do not produce a loud sound when struck with a hard object.

This concludes my talk on non-metals.

Basics of Chemistry-Metals

As we discussed earlier,elements can be further classified into two categories-
Metals and Non-Metals
Metals
Metals can be defined as-Any element which is a good conductor of heat and electricity.

Metals also have other properties-

Physical property
Most metals are found in solid form in nature.The only liquid metals at room temperature are Mercury,Gallium,Caesium,Francium,Rubidium.

Lustre
 Metals usually give a shine when polished.This is called lustre.

Colour
Most metals are white or silvery grey in colour.Exceptions are Gold which is yellow in colour and Copper is reddish-brown in colour.

Hardness
Most metals are hard with the exceptions of Potassium and Sodium that are so soft that they can be cut with a knife.

Malleability
Most metals can be beaten into thin sheets or foils.The property by virtue of which metals can be beaten into thin sheets or foils is called malleability.For example,aluminium can be beaten into foils.

Ductility
The property by virtue of which metals can be drawn into thin wires is called ductility.Due to this property,metals can be stretched into wires.For ex: Copper wires.Gold and silver are the two most ductile metals.

Thermal Conductivity
Most metals are good conductors of heat.This property is known as thermal conductivity.Due to this property,heating vessels and pans are made from metals.

Electrical conductivity
Metals are good conductors of electricity.This property is known as Electrical conductivity.Due to this property,wires are made from metals.

Sonority
Most metals produce loud sounds when struck with a hard object.The property by virtue of which metals produce a loud sound when struck with a hard object is called Sonority.This property is used in Bells,Wind chimes etc.

This concludes my talk on metals.