Magicians are not the only ones who can
change one material into something completely different. Did you know
that scientists, nature, and even you can change one material into
We call this “magic” a chemical reaction.
a chemical reaction, matter is changed from onesubstance to
Burning wood changes the wood into ash. Water will react
with iron to form a new product. Do you know what it is? If you have ever
left your bicycle in the rain you probably know it is called rust.
Chemical reactions may also produce
heat, light, bubbles or color changes. When
the bike rusted, the metal turned a different color so we know that a
chemical reaction occurred between the bike and the water. Please remember
that not all color changes prove that a chemical reaction has taken place.
A physical change is different than a chemical change.
Things that are changed physically do not turn into something else.
Breaking a match in two pieces is an example of a physical
change. Lighting a match and letting is burn is an example of a chemical
reactions cause chemical changes. In a chemical reaction two
or more substances, called the reactants, form different
substances called products. In the above examples the
wood and oxygen were the reactants that, when heated, formed
the products of ash and smoke (gases). Water, iron, and oxygen
were the reactants that formed the product called rust.
+ oxygen (heat)
+ iron + oxygen
would happen if you were to change one of the reactants in a chemical
reaction? What if, instead of water, you put grease or oil on
your bike? Would you still get rust? Of course not. You would
get a greasy bike!
Not all substances will react with each
other. Grease + iron + oxygen will not cause a chemical reaction.
Changing the reactants will change the results of the experiment.
Examine the left side of the chart below. Decide
if the action taking place is a physical change or a chemical
reaction. Click and drag to your answer in the column on the right.
Then check your answers by highlighting the box below. Good luck!
1. Glass breaking
2. Ice cube
3. Candle burning
4. Food digesting
in your stomach
7. Lake freezing
8. Bread baking
9. Sugar dissolving
burning in an engine
change, 2. Physical change, 3. Chemical change, 4. Chemical change,5.
Physical change, 6. Chemical change, 7. Physical change, 8. Chemical
change, 9. Physical change, 10. Physical change, 11. Chemical change,
12. Physical change
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