Introduction, Slow and Fast changes

EARNING OBJECTIVES:
         Introduction
         Classification of changes
         Slow and fast changes
         Reversible and Irreversible changes
         Desirable and undesirable changes
         Periodic and non periodic changes
         Physical and chemical changes
         Characteristics of physical and chemical changes
         
Real LIfe Applications:
    No new chemical species forms in a physical change. Changing state of a pure substance between solid, liquid, and gas phases of matter are all physical changes, since the identity of the matter does not change,melting an ice cube,casting silver in a mold,breaking a bottle
    A new compound (product) results from a chemical change as the atoms rearrange themselves to form new chemical bonds.burning wood,souring milk,mixing acid and base,digesting food,cooking an egg,heating sugar to form caramel,baking a cake
Introduction:
        In our daily life, we observe many changes a round us everything in this universe undergoes a change. These changes may be observed by us at school, home, play ground, garden or any other place.The changes can bring about different kinds of alterations in things around us. Some of the alterations brought about are permanent in Nature and other are temporary in Nature are permanent in Nature and other are temporary in Nature.

Classification of changes: The changes taking place around us can be classified as under
    1) Slow and fast changes                2) Reversible and irreversible changes
    3) Desirable and undesirable changes     4) Periodic and non periodic changes
    5) Physical and chemical changes.
Slow and fast changes:
    Fast Changes        
        Some changes are very fast. These changes occur with in seconds (or) minutes.
        Fast changes happen quickly and are easier for humans to notice; for example, when some one throws a ball, it goes up into the air very high but then falls back down fast.
    Some more examples of fast changes are
            Burning of a match stick 
            Bursting of a cracker
            Spinning of a top
            Bursting a balloon.
            Breaking a window
            Earthquakes
            Volcano eruption
            Floods
            Landslides
    Slow Changes    
        Some changes take place very slowly. These changes may take hours, days, months (or)     years to complete.
        Slow changes cannot be felt or noticed by humans because they are gradual and do not feel like much is happening.  For example, plants become more cold-resistant when they experi ence cold temperatures every winter. Humans also experience slow changes, such as the growth of human cells or bones. Slow changes occur because of cell division and biological processes. 
    Some more examples of slow changes are
            Rusting of an iron.
            The water changes into ice in a fridge in a few hours.
            Ripening of fruits
            Day and night formation
            Movement of the continents
            Weathering 
            Erosion
            Deposition