Designing Cohesive Lessons ~
Teaching Science in Middle and
Secondary Schools
MARK VOLKMANN
UNIVERSITY OF MISSOURI
COLUMBIA, MO
Design a Lesson Sequence:
 Good lessons have a story line.
 Good lessons challenge students’ misconceptions
 Good lessons help students develop evidence–based
explanations.
Designing a Story-Line
 Start with 4 questions
1.
What do you want students to learn? – the concept
2.
How should the lesson begin? – the phenomenon
3.
What representation should students understand?
4.
What instructional steps connect the beginning
phenomenon with the ending representation?

What do you want students to learn?
 The GLE for learning density: Objects, and the
materials they are made of, have properties that
can be used to describe and classify them. (Strand
1.1. A)
 Compare the densities of regular and irregular objects using
their respective measures of volume and mass (DOK 3)
 Identify pure substances by their physical and chemical
properties (i.e., color, luster/reflectivity, hardness,
conductivity, density, pH, melting point, boiling point,
specific heat, solubility, phase at room temperature, chemical
reactivity) (DOK 1)
How should the lesson begin?
 If I place this vegetable into water, will it sink or
float?
 What does this have to do with density?
What representation should students understand?
 What is the Mass to Volume ratio for each of the
objects?
 The mass to volume ratio is recognized by scientists
as a very important quantity called density.
 Density is the ratio of the mass of a substance to its
volume.
What instructional steps connect the beginning phenomenon
with the ending representation?
Four Principles of Learning
 Principle #1: Prior learning matters
 Principle #2: Learning is social
 Principle #3: Students need to understand and
frame knowledge
 Principle #4: Self-monitoring is key
Let’s practice these four steps
What do you want students to learn? – the
concept
2. How should the lesson begin? – the phenomenon
3. What representation should students
understand?
4. What instructional steps connect the beginning
phenomenon with the ending representation?
1.
Grade Level Expectation - Density
 The GLE for learning density: Objects, and the
materials they are made of, have properties that
can be used to describe and classify them. (Strand
1.1. A)
 Compare the densities of regular and irregular objects using
their respective measures of volume and mass (DOK 3)
 Identify pure substances by their physical and chemical
properties (i.e., color, luster/reflectivity, hardness,
conductivity, density, pH, melting point, boiling point,
specific heat, solubility, phase at room temperature, chemical
reactivity) (DOK 1)
Applying Principles to Teaching Density
 Begin instruction with a question! Ideally, the
question intersects with an interest of their own.
 Begin with a concrete phenomena and move to
an abstract concept.
Concept
Phenomena
Teaching Sequence – How do we decide?
 Measure the mass and volume of an object to find







density
Explore students’ explanations
Give a lecture explaining density
Demonstrate density phenomena
Practice density problems
Assess prior ideas
Apply density concepts
Evaluate student learning of density
Applying Principles to Teaching Density
 If I place this vegetable into water, will it sink or
float?
 What does this have to do with density?
Engaging and Eliciting Student Thinking
Object
Large Block of Wood
Small Block of Wood
Flat Aluminum Foil
Aluminum Block
Large Candle
Birthday Candle
Potato
Apple
Carrot
Silly Putty
Lava Rock
Sink
Float
Reason
Student Ideas: What does the Research Say?
 Students’ pre-conceptions about floating and sinking:
Float
Sink
Weight
Light
Heavy
Size
Small
Large
Shape
Flat (2d)
Solid (3d)
Air
Contain air
No air
 Driver, R., Squires, A., Rushworth, P., & Wood-Robinson, V. (1994).
Making sense of secondary science: Research into children’s ideas.
London: Routledge Press.
Students’ Explanations
 What is the role of Mass?
 What is the role of volume?
 What is the role of air?
 What is the role of shape?
Challenge Students’ Ideas
Object
Mass
(g)
Size
(cm3)
Shape
Air
other
Float/
Sink
Large Block of Wood
300
500
Rectangle
N
F
Small Block of Wood
60
100
Cube
N
F
Flat Aluminum Foil
5.4
2.0
Flat
N
S
Aluminum Block
110
40.
Cube
N
S
Large Candle
405
510
Cylinder
N
F
Birthday Candle
4.1
5.2
Cylinder
N
F
Potato
253
245
Oblong
N
S
Apple
159
170
Sphere
N
F
Carrot
109
95
Taper
cylinder
N
S
Silly Putty
75
65
spherical
N
S
Lava Rock
148
110
oblong
Y
S
What is the Role of Water?
Sample
Mass (g)
Volume(cm3)
A
10
10
B
60
60
C
200
200
D
350
350
E
500
500
Mass
The Role of Water
Volume
Mass
A Graphical Representation Comparing Mass
to Volume
Volume
Mass
Potato? Apple? & Carrot
Volume
Potato
253
245
Apple
159
170
Carrot
109
95
Puzzler
 An egg has a mass of 54 grams and sinks in water.
What is the volume of the egg? Is it greater than 54
cm3 or less than 54 cm3? Why do you think so?
 If we placed the egg data on the graph for water,
would the egg be located above or below the line for
water?
Developing a Conceptual Explanation
 What is the Mass to Volume ratio for each of the
objects?
 The mass to volume ratio is recognized by scientists
as a very important quantity called density.
 Density is the ratio of the mass of a substance to its
volume.
Apply the Concept of Density to a new Context
What would happen if we placed each object in
alcohol? Would the object float or sink?
What do you know about floating and sinking in
water that will help you answer this question?
What information do you already have?
What new information do you need to learn?
Elaboration: A Graphical Representation for
Alcohol
Application of Density to a
Float or Sink in Alcohol:
Object
Density (grams/cm3)
Float or Sink?
Large Block of Wood
0.78
F
Small Block of Wood
0.78
F
Flat Aluminum Foil
2.71
S
Aluminum Block
2.71
S
Large Candle
0.82
F
Birthday Candle
0.82
F
Potato
1.05
S
Apple
.95
S
Carrot
1.02
S
Silly Putty
1.55
S
Graphical Representation for Alcohol
Potato
253
245
Apple
159
170
Carrot
109
95
How can we know that students have learned?
 What activities reveal student learning?
 Talk to a neighbor.
 How can you know in a classroom whether students
have learned?
Summative Evaluation #1
 If liquid A (density = 2.5 g/cc) is poured into liquid B
(density = 3.0 g/cc), which will float? Why?
 If liquid C (density = 1.2 g/cc) is poured into liquid D
(density = 3.5 g/cc), which will float? Why?
 If A and B are poured into C and D, what will be the
order of floating from top to bottom? Why?
 If a marble (density = 2.0 g/cc) is dropped into this
column of liquids where do you predict it will float?
Why?
Summative Assessment #2
What measurements, or combination of
measurements, would you use to predict if an
object will float or sink?

1.
2.
3.
4.
Mass
Volume
Shape
Air
Summative Assessment #3
 A sample of gasoline has a mass of 50.0 grams and a
volume of 60.0 cubic centimeters. What is the
density of the gasoline?
Summative Assessment #4
 A sample of lead has a mass of 44 grams and a
volume of 4 cubic centimeters. What is the mass of a
sample that is 8 cubic centimeter?
Summative Assessment #5
 Does the Rootabega Sink or Float?
 What information do you need to make a prediction?
What about density?
Prior learning matters.
2. Learning is social.
3. Students need to understand and frame
knowledge.
4. Self-monitoring is key.
1.
What is your metaphor for teaching and learning?
Director
Filling Station
Gardener
Guide
Do learners acquire knowledge?
Do learners construct knowledge?