lesson plan

1. Density and Relative Density
A. Background Information
1. Jennifer Anders
2. Physical Science
3. Density and Relative Density
4. 5th Grade
B. TEKS and NGSS
1. TEKS:
112.16.B.2.D – analyze and interpret information to construct reasonable
explanations from direct (observable) and indirect (inferred) evidence
112.16.B.2.E - demonstrate that repeated investigations may increase the
reliability of results
112.16.B.2.F - communicate valid conclusions in both written and verbal
forms
112.16.B.3.A - in all fields of science, analyze, evaluate, and critique
scientific explanations by using empirical evidence, logical reasoning, and
experimental and observational testing, including examining all sides of
scientific evidence of those scientific explanations, so as to encourage
critical thinking by the student
112.16.B.5.A - Classify matter based on physical properties, including
mass, magnetism, physical state, solid, liquid, and gas, relative density
sinking and floating, solubility in water, and the ability to conduct or
insulate thermal energy or electric energy.
2. NGSS: Second Grade: 2-PS1-1. Plan and conduct an investigation to
describe and classify different kinds of materials by their observable
properties.
C. Goals and Objectives
1. Objective(s):
 The student is expected to compare which objects sink or float in
water.
 Students will make predictions and test 2-4 objects (such as golf balls,
ping pong balls, whiffle balls, foam balls, metal and wood cubes, etc.)
to determine their relative density. Students will also conduct a lab
activity predicting and testing the relative densities of liquids,
including salt water.
2. Materials Needed (for 20 students in five groups of four students
each):
i. 5 - Aquariums or large, clear containers to hold water,
ii. Enough water to fill aquariums about half full
iii. 5 - Coca-Cola (unopened),
iv. 5 - Diet Coke cans (unopened),

2. v. 5 - Bars of Ivory soap (travel size),
vi. 5 - Bars of Dove soap (travel size),
vii. 10-20 - Variety of objects with different densities such as golf ball,
ping pong ball, beads, cubes of metal and wood, etc.
viii. 1 - Large container of Kosher Salt,
ix. 2 - Bottles of Food Coloring (two different colors),
x. 10 - Clear Drinking Straws (cut in half),
xi. 20 - Droppers/Pipets,
xii. Paper towels (for spills),
xiii. Relative Density lab chart for Science IN.
3. Technology that is needed:
i. Projector
ii. Document Camera
4. Safety:
i. Students should practice safe lab procedures by handling all
materials properly.
ii. Students should refrain from consuming food or drink in the science
lab.
iii. Students should quickly clean up any spills during lab and wash
hands thoroughly after lab activity.
5. Vocabulary (sources: Stem Scopes, dictionary.reference.com/science):
i. Mass – the amount of matter in an object
ii. Density – the amount of mass in a known volume of a substance
iii. Relative Density – the ratio of the density of one substance to that of
a reference substance, typically water.
iv. More dense (than water) – object will sink
v. Less dense (than water) – object will float
D. Background Information (for the teacher):
Students are likely unfamiliar with the term “relative density.” Explain to students that
this term is the relationship between an object’s density and something else (typically
water). An example would be Italian dressing. When it rests, the oil floats to the top
because it is less dense than the water. Students may have misconceptions regarding
density especially when discussing volume without referring to weight. Children often
persist that an object sinks because of its weight and, without exploration, have difficulty
grasping the ideas of weight and volume independently. Students need to be given many
opportunities to investigate both volume and mass – independent of one another – in
order to fully grasp the understanding of the effects the two variables have on
floating/sinking.

3. The density of water is 1.0 g/cm3. Objects with a density greater than water sink. Objects
with a density less than water will float.
Object > 1.0g/cm3 = Sink
Object < 1.0g/cm3 = Float.
E. Procedures
1. Setup: Each lab table has the following:
i. One aquarium half filled with tap water,
ii. One Coca-Cola can (unopened), one Diet Coke can (unopened),
iii. One bar of Ivory soap, one bar of Dove soap,
iv. Assortment of objects in pairs of same shape/size but differe nt
densities,
v. Beaker filled with colored tap water,
vi. Beaker filled with colored salt water,
vii. Droppers/pipets (2-4 in the regular water and 2-4 in the salt water),
viii. Clear straws (one per student).
ix. Paper towels as needed for spills
2. Engage: What causes an item to float in water? What causes an item to
sink in water? The object’s size and weight determine whether it will sink
or float in water. Predict what will happen when the objects are placed in
the water. The regular soda will sink and the diet Coke will float. Explain
why. The regular soda has more sugar in it, making it denser than the diet
Coke. Because it has a higher density, the regular soda sinks. The diet Coke
has a lower density and floats.
Students will observe any noticeable differences between the Coke and Diet
Coke cans, including estimating any weight and size differences. After they
have recorded their observations and hypothesis regarding the sinking or
floating of the cans, the students will test them by placing both cans into
their table aquarium, observing and recording their findings, including why
they think it happened.
3. Explore: Why do you think certain objects are floating? They have less
“stuff” in the given size of the object. Why do you think objects of the same
size and shape react differently in water? Some have less “stuff” in them
and others have more. Group objects based on whether they sink or float.
Students will make predictions on the other solid objects on the lab tray and
record their predictions on the provided lab chart that will be glued into their
science interactive notebooks. After each item, the students will record
whether or not their predictions were supported.
4. Explain: How would you Density? It is how much “stuff” is in a given
amount of volume. What about Relative Density? It is the comparison of
the density of an object to something else, typically water. Discuss how
relative density relates to the objects sinking or floating. When objects
have the same volume, the mass will determine whether the object will sink
or float. Density = Mass/Volume. If the density is greater than 1.0 g/ cm3,
the object will sink. If the density is less than 1.0 g/ cm3, the object will

4. float. Students discuss in groups why they think certain materials float and
others sink even when they are the same size and then discuss as a class
what the students discovered during the lab activity.
Misconceptions: students may experience the inability to explain density
especially when having to discuss volume without referring to weight. When
children are asked to explain why a larger item displaces more water than a
smaller item, they often persist that it is due to the item’s weight, not volume .
It seems that after much exploration, most students have a firm grasp of the
ideas of weight and volume independently. However, when asked to address
the question of what makes things float, they often attribute the cause only to
weight and fail to integrate volume into the equation. Students need to be given
many opportunities to investigate both, volume independent of mass and mass
independent of volume to gain a thorough understanding of the effects of each
variable on floating.
5. Elaborate: What if we add salt water to the regular water in the aquarium.
The salt water will be denser than the regular water because it has more
“stuff” in it. What will happen to the objects when placed in the tank? If
they floated in regular water, they will still float. If they sank in the regular
water, they might float above the salt water but below the regular water, or
they might sink to the bottom. Students will complete the salt water density
portion of the lab individually to determine the difference in density
between salt water and regular water. The students will record their
predictions in their lab science journal, perform the lab, and record their lab
results. Discuss lab outcome with group.
6. Evaluate:
i. Formative Assessment:
1. Questioning during labs
2. Science Interactive Notebook recordings, including
predictions and conclusions.
3. How could you separate items that are different densities?
Explain.
ii. Summative Assessment:
1. Assessment with multiple choice questions as well as a lab-based
activity requiring students to determine the density of
an object and predict its relative density to water. Test and
write conclusion. Students can create a T-chart with objects
that are more/less dense than water. Objectives will be
considered met if the student is able to predict, test, and
explain/conclude their reasoning in regards to objects’
density and relative density in comparison to water.
F. Modifications –
1. ELL students
i. Extended wait time (minimum of 5-6 seconds)
ii. Picture vocabulary words
iii. Four Box Vocabulary/Frayer Model for Vocabulary
1. Definition
2. Image/Use it in a sentence

5. 3. Non-examples/Antonyms
4. Examples/Synonyms
iv. Sentence Stems and/or shortened descriptions of experiment
v. Note taker/Notes provided
vi. Adjust the evaluation/grading criteria
vii.
2. SpEd students
i. Extended wait time (minimum of 5-6 seconds)
ii. Modified questions on assessment (three instead of four choices on
multiple-choice portion)
iii. Note taker/Notes provided
iv. Lab assistant
v. Additional time for tests, assignments, in lab
vi. Preferential seating
vii. Adjust the evaluation/grading criteria
viii. Assistive technology
ix. Visual cues to stay on task
3. GT students
i. Provide extended questions for students:
1. Suppose we had four beakers with 100 mL of water in each
one. The first beaker is just plain tap water. The second
beaker has 3 grams of salt dissolved into the water. The
third beaker has 0.5 grams of salt dissolved into the water.
The fourth beaker has 5 grams of salt dissolved into the
water. Can you list the beakers from least dense to most
dense? Explain your reasoning.
ii. Extension activities:
1. Design submarines:
a. Three different types of submarines – a floating
submarine, a sinking submarine and a hovering
submarine that is completely underwater but is not
touching the bottom given the following
objects/items per student (may work in pairs/small
groups): three film canisters, variety of small, heavy
objects (coins, washers, marbles, screws), variety of
small, light objects (paper clips, corks, beads,
Styrofoam), rubber bands or string, large containers
of water.
b. Have students write down observations about what
they did to get the submarines to sink, float, and
hover.
2. Practice testing density of different liquids and the density
of objects in those liquids:
a. Have beakers of the following liquids: vegetable oil,
light corn syrup, water (colored blue for visibility),

6. rubbing alcohol (colored red for visibility), and
baby oil.
b. Have students predict the densities of the liquids
and then test them and record the results (should
layer from most dense/bottom to least dense/top as
follows: corn syrup, water, vegetable oil, rubbing
alcohol, baby oil.
c. Provide a variety of small objects (cork, plastic
toys, nuts/bolts, Styrofoam, etc.) Have students
predict where the objects will float when dropped
into the graduated cylinder containing the liquids.
G. Integration of Mathematics and Language Arts
 Math – Students will use math to determine density of objects. Students
will also use tools, including a triple beam balance to determine the mass,
a graduated cylinder to determine volume, estimation in measuring water
using beakers and pipets/droppers.
o TEKS 5.1A apply mathematics to problems arising in
everyday life, society, and the workplace;
o 5.1C select tools, including real objects, manipulatives, paper
and pencil, and technology as appropriate, and techniques,
including mental math, estimation, and number sense as
appropriate, to solve problems
 Language Arts – Students will complete the assigned lab given the
instructions and reading material provided. Students will interpret
information based on graphs/tables created during lab activity.
o TEKS 5.13A Interpret details from procedural text to complete
a task, solve a problem, or perform procedures.
o 5.13B Interpret factual or quantitative information presented
in maps, charts, illustrations, graphs, timelines, tables, and
diagrams.
H. References
 19 TAC Chapter 112, Subchapter A. (n.d.). Retrieved October 6, 2014, from
http://ritter.tea.state.tx.us/rules/tac/chapter112/ch112a.html
 5.5A Classifying Matter. (n.d.). Retrieved October 6, 2014, from
https://ali3.acceleratelearning.com/scopes/87/elements/5080
 BIG Science Stations Units: Physical Science. (n.d.). Retrieved October 6, 2014,
from http://www.thesciencepenguin.com/2014/08/big-science-stations-units-matter.
html
 Dabagyan, E. (2007, January 1). What Makes Things Float? Density and
Buoyancy Misconceptions. Retrieved October 13, 2014, from Dabagyan, E. (n.d.).
What Makes Things Float? Density and Buoyancy Misconceptions. Retrieved
October 13, 2014, from
http://www.csun.edu/~eed39911/coursework/690/Density%20Misconceptions%2
0Paper.pdf
 Density and Floating. (n.d.). Retrieved October 6, 2014, from

7. http://www.newton.dep.anl.gov/askasci/phy00/phy00136.htm
 Density Bottles Activity Fun! (2014, September 16). Retrieved October 6, 2014,
from http://www.thesciencepenguin.com/2014/09/density-bottles-activity-fun.html
 Density Lesson Plan. (n.d.). Retrieved October 6, 2014, from
http://wordsinplay.com/pdfs/DensityLessonPlan.pdf
 RESCU | Engage: Classifying Matter (5.5A). (n.d.). Retrieved October 6, 2014,
from http://rescu.rice.edu/scope/80/engage

8. Lab sheet for Interactive Notebook:

9. Definition page for Interactive Notebook: