LESSON PLAN
Name: Kristin
Vander Voord
Title of lesson: Density Lecture
Length of lesson: approximately 50 minutes
Source of the lesson:
Snyder,
Carl. The Extraordinary Chemistry of
Ordinary Things. John Wiley:
http://www.sci.mus.mn.us/sln/tf/l/liquidlayers/liquidlayers.html
http://www.thirteen.org/edonline/nttidb/lessons/as/derbyas.html
TEKS addressed:
Give identification number and letter and write out
the TEKS.
I. Overview
Density is one of the
hardest concepts to teach to students.
While many can memorize the formula, few students understand what it
means. In order to introduce the topic
for future exposure, this lesson will try and touch upon what density is and
what affects it.
II. Performance or learner outcomes
Students
will be able to:
1.
Define density
as the mass of a substance per unit volume.
2.
Predict what
will happen to the density of an object as the parameters are changed.
3.
Differentiate
between mass and weight.
III. Resources, materials and supplies needed
·
Tank of water
·
Can of Coke and
a Can of Diet Coke
·
Four 2 liter
bottles filled with: cotton balls, water, iron filings, and air
Five-E Organization
Teacher
Does Probing Questions Student
Does
|
Engage: 5-10min Before students arrive have a clear tank of water
in the front of the room, a can of Coke and a can of Diet Coke. As students arrive, as them to take their
seats. “Who in here drinks Coke?”
(hold up the Coke can) “For those of
you who are watching calories, I also have a can of Diet Coke.” Ask the students to predict what will
happen when you place the two cans in the tub of water. “Any guesses?” Call on one or two students to make a
prediction and ask why they believe that will happen. Tally on the board their responses to
float/not float for each. Do not
acknowledge their hypothesizes as being right or wrong. “Well lets see, shall we…” Place the two cans in the tank of
water. The result of this will be that
the can of Coke will sink and the Diet Coke will float. “Maybe that is why people say Diet Coke is
lighter in calories.” Ask the students
why they think the Coke sank and the Diet floated. Answers may include that the Coke weights
more or is denser. Some may think it
is because there is more in the coke can, note to them that they are the same
volume. Ask the students to write down
their ideas. Let them know they will
be looking back on their hypothesizes after the discussion. |
Questions: Who drinks Coke? What will happen if I place these two cans in the
water? Any guesses? Why do you think the Coke can sank? Or the Diet can floated? |
Expected Student Responses/Misconceptions I do. They will float. They will sink. The Coke was heavier
than the Diet. The Coke was denser
than the Diet. |
|
Explore: 20-30 min “How many of you have heard of the term
Density?” Wait for student
responses. “Anyone know what it
means?” Explain that most text books
will explain the term density as the mass of an object per unit volume. The mass of an object is not to be confused
with the weight of an object. “Tommy,
what is the difference between mass and weight?” Answers may vary. If someone suggest that weight takes into
consideration gravity, go with that.
So if I were to go to the moon, what would be different about me? The desired answer is “your weight” because
my mass is a fixed amount that does not change with location. So the stuff that is inside of me is not
going to change but the pull of the earth or the moon does change. However, my mass can change. If I were to load up on all the junk food
in the world I would gain mass. My
weight would increase because my mass increased (the pull of gravity did not
all of a sudden change). Getting back
to density, it is also different than weight.
“Have any of you fished before?
Have you used the little lead sinkers?” Now lead is thought of as a heavy metal,
but what we really mean is that it is dense.
So that sinker weights a small amount and is small enough to hold in
the palm of a hand but when on a line and tossed into water, it sinks. Now take for example a tree, what happens if a huge tree were to fall
over on my car? What would happen to
my car? It would be crushed
right. But what happens when that same
tree falls onto a lake? It
floats. Why? Because it is less dense than water. What are the three things we are looking at
in this? Density, mass, and
volume. These parameters form the
equation you will all learn to love. D
= M/V. Using your knowledge of math,
what will happen to density if I increase the mass of a substance but keep
the volume the same?(If I have two balls the same size and one was made of
lead and the other made of wood?) What
will happen if I increase the volume of that substance and keep the mass the
same? |
Questions: How many of you have
heard of the term Density? Anyone know what it
means? Tommy, what is the
difference between mass and weight? What would happen if I
were to go to the moon? Have any of you fished
before? Have you used the little lead sinkers? What happens if a huge
tree falls on my car? Why? (Tree is heavy and force would smash car) Falls in a lake? Why?(Tree may be heavy but
mass is “spread out” in large volume so density is low) What are the three
things that keep coming up in this discussion? What will happen if I
increase the mass of something, but keep the volume the same? What if I increase the
volume but leave the mass the same? |
Expected Student Responses/Misconceptions Misconception:
density=weight Density is mass divided
by volume. “Nothing” Weight takes into
consideration gravity. You would weigh less. Yes The car would be
crushed. The tree would float. Mass, Volume, Density The density would increase. The density would decrease |
|
Explain: 5-10 min So taking this all into consideration, lets go back
to the cans of soda. Why do you think
the Coke sank and the Diet Coke floated?
Wait for responses. Now
remember that the cans are the same volume, what must be different? The mass of the Coke must be more than that
of the Diet Coke. What is actually
happening is that Diet Coke uses an artificial sweetener called aspartame
instead of sugar. It takes much less
sweetener to get the same sweet taste that sugar gives soda. Less sweetener means less mass. What does that mean? The Diet Coke is less dense. So now you can all trick your friends and
teach them some science at the same time. |
Why did the Coke sink
and the Diet float? What must be different? What does this mean? |
Expected Student Responses/Misconceptions Because the Coke is
more dense. The mass of the soda. The mass of Coke is
more than that of Diet. |
|
Extend / Elaborate:
5-10 min In the front of the
class have four 2 liter bottles. Have
them filled with cotton balls, water, iron filings, and air. Ask the students what is the same between
these four bottles. Each bottle is 2
liters in volume. What is
different? The weight (mass). Which do you think is denser? Why? |
Questions: What do these bottles
have in common? What is different? Which is denser? |
Expected Student Responses/Misconceptions The shape, size,
volume. The mass, color, stuff
that is inside. The iron filings. |
|
Evaluate: Questions through out
will serve as assessment to make sure the students are meeting the objectives
of the lesson. |
Questions Refer to questions
through out the lesson |
Expected Student Responses/Misconceptions Refer to responses
though out the lesson |