Pretty much all around us there are things in a process of change. Trees are in the woods, then cut down to become wood. Logs are split and stacked into cords ready to be burned for heat, changing to ash in the process.
Apples, or any fruit on a tree grows ripens, gets picked and is usually eaten, providing fuel for human or animal or insect bodies. If left to sit it will decay of its own process and if composted it can become a sort of fuel, actually a fertile food for soils.
Cider if left exposed to air will change into vinegar. Milk can change to butter or cheese.
These changes of common things from one substance into another is called a chemical change.
Chemistry is the science that works to explain the changes of substance.
In a chemistry lab experiments or processes are done to explore and understand what are some of the underlying mysteries cause changes in the material world. A century ago, and maybe still today, a simple experiment would be to show how one material can be broken up into two new materials. An experiment from 1914 using mercuric oxide, a red powder, was be done by putting the powder in a test tube and heating it. As the heating progressed it would be noticed that on the cooler portions of the tube drops of silvery white liquid which was recognized as quicksilver or mercury. As the experiment continued the students in the lab would take a splinter of wood, like a match stick I am thinking, light it on fire but put the flame out to leave only the glowing embers. Then the wood splinter, would get plunged into the tube above the red powder and those watching would see it burst into flame.
Since the spark of heat would only glow in the air of the room, it seems the air, -or gas- in the tube must be different from the room air. Oxygen. The oxygen gas in the room, most any room, is only a fifth, ⅕ of ordinary air.
This red powder was changed inside the heated tube into oxygen, a colorless gas and also changed into the silvery liquid, quicksilver. So what happened was the mercuric oxide was changed into two substances of different properties. When heated the powder was chemically changed into a gas and a liquid form. The chemical change is also called decomposition, something decomposes and seemingly disappears but actually has changed into something else.
It has been recorded in history that a man named Joseph Priestley born in 1733– died in 1804 was the first person known to discover this change in mercuric oxide. He was born almost 300 years ago. This experiment came from a book written over a hundred years ago.
If you want to keep going with the changing of matter into different substances lets move from the solid powder form and look at liquids and the Decomposition of Water.
