So what's the big deal if I don't brush the way I should?
Objectives:
Students will
understand the destructive nature of plaque acid in their
mouths.
Students will
use the scientific method for proving a hypothesis.
Materials:
2 small jars
with lids
Label
Marker
Pieces of eggshell
Water
White vinegar
Science journals
Pencils
Preparation:
Assemble materials
Instructions:
1.
Ask students what
they know about tooth decay.
2.
Explain that you
will be conducting a scientific experiment today on
what happens when teeth are not properly cleaned and
the acids produced by plaque attack the teeth.
3.
Explain that vinegar
is a mild acid. If we do not brush our teeth, plaque
forms and gives off acids very similar to vinegar. Also
explain that one of the materials that make up eggshells,
calcium, is also an important substance in teeth. For
the experiment, you will be using eggshells to represent
teeth, and vinegar to represent the acids in plaque.
The second jar with eggshells in water is the control,
or something you will use to compare the findings in
the jar with vinegar.
4.
Place several pieces
of an eggshell into each of the two glass jars and ask
the students to hypothesize, or make their best guess,
at what will happen when you put water in one jar and
vinegar in the other.
5.
Have them record their
ideas in their science journals.
6.
Now fill enough water
into one jar to cover the eggshells and do the same
with vinegar in the other jar. Label and date the two
jars.
7.
Let the students
observe the contents of the two jars and note anything
they see. (Small bubble will form on the eggshell in
the vinegar - this is a chemical reaction).
8.
Explain that this
is similar to what happens when you eat. Acids in your
mouth, much like the acids in vinegar, react with the
food and start to break it down. Some acid is helpful
for us to digest our food but, unless we brush and floss
regularly, we could have too much of it, which is harmful
to our teeth.
9.
Ask the students
to come up with a hypothesis of what will happen if
you leave the vinegar and eggshell in the jar for several
days. They should write this in their journals and at
the end of the experiment can check to see if they guessed
correctly.
10.
Observe the changes
that take place twice a day and have the students record
these in their science journals.
11.
In two or three days,
the acids in the vinegar will dissolve the eggshell.
The eggshell in the jar with water will remain unchanged.
Explain that the acids in the vinegar are similar to
the acids that attack the enamel in our teeth. If teeth
are not brushed and flossed, the enamel can begin to
dissolve and allow cavities to form.
