Physical and Chemical Changes

PHYSICAL CHANGES

1)Shredding Paper

While shredding a sheet paper in my house,I noticed that no new substance was created and there was only change in the size and shape of the matter(paper). This is a physical change as no chemical reaction occurred and no new substance was formed.

2)Breaking a Glass

While drinking water, my glass fell accidentally fell on the ground and shattered into pieces. This is a physical change as the glass takes different size and shape on breaking but the composition of the shattered glass pieces remains the same as that of the original glass. There is no change of color from the original piece.

3)Mixing Sand and Water

Some children were mixing sand and water together. I noticed that it was a physical change because during mixing, the substances do not react chemically with each other to produce any gas, color or sound and they can be converted back to sand and water.

CHEMICAL CHANGES

 

1)Rusting of Iron

While playing around in my compound, I observed rusting on some fences.This happens due to humidity in the area. These are chemical changes as these are the results of the process of oxidation and can not be converted back to their original form. The texture also changes and it becomes flaky. The color turns reddish brown.

2)Burning of Firecrackers

During festivals, lots of firecrackers are burned. The burning of firecrackers are chemical changes as we notice the combustion reaction. The state also changes and the powder in the firecracker turns into harmful gases and emits light,odor and sound. This change is irreversible.

3)Using a Chemical Battery

While using batteries in my torch, I realized that there was a chemical change happening. The batteries use electrochemical energy, a chemical reaction to produce electrical energy and as this can not be turned back to chemical energy, it is irreversible.

Regards,

Nalini Singh