Los Angeles Charter Schools Science Partnership
Model-Based Inquiry Lesson Plan
Lesson Title: Chemical Reactions
Topic/ Focus Area: Physical Science
Grade 5
Major Concept of Lesson:
In a chemical reaction, the original material becomes a new substance(s) with properties that are different from the
original substance (s). Burning a match, photosynthesis, and rusting iron are all chemical reactions. In each case
the chemical composition has been altered. In a chemical reaction the bonds holding the molecules are broken and
the atoms reform into different molecules. Some indicators that a chemical reaction has taken place include a color
change, a temperature change, gas production, light/sound/odor production.
Model:
Key Question: What is a chemical reaction?
Students will produce written and diagrammatic representations (models) of what a chemical reaction is.
California Standard(s) to be addressed: (Grade, Strand, Standard, Substandard)
5th
Grade, Physical Science
1.a Students know that during chemical reactions the atoms in the reactants rearrange to form products with
different properties.
1.g Students know properties of solid, liquid, and gaseous substances, such as sugar, water, helium, oxygen,
nitrogen, and carbon dioxide.
Student Objectives:
 Students will record observations of matter before and after a chemical reaction.
 Based on investigation observations and a selected reading, students will create a model of what a chemical
reaction is and what it involves.
 Students will revise their model of chemical reactions based on new learnings and observations.
 Students will apply their model to complete a task that involves the identification and justification of a
chemical reaction (in Elaborate).
 As part of the Reading Cycle Literacy Activity, students will engage in questioning, predicting,
distinguishing main idea from details, paraphrasing, creating visual notes, and summarizing.
Materials and Resources:
Engage:
 Bread (two slices)
 Toaster
 Baggie to place toasted bread for observing water vapor
Explore:
Per Group:
 Baking soda-2 teaspoons
 Calcium chloride-1 tablespoon
 Phenol red solution-1 teaspoon or 5 ml
 Small bottle of water (2 teaspoons)
 One quart-size good quality ziplock baggie






Goggles
Gloves
Paper towels
Small plastic medicine or salsa cup
Waste container
Plastic teaspoons labeled: calcium chloride, baking soda, water, phenol red solution.
Handouts:
 Student Observation Chart
 Procedure for Lab: “Reaction in a Plastic Baggie”
 The Reading Cycle (Procedure sheet for teachers)
Lesson Implementation Logistics:
See instructions for the teacher for the Calcium Chloride Lab
Review safety precautions on the handling of chemicals
Consider teaching the following knowledge and skills before this lesson: definition of “indicators’, the difference
between observations and procedures
If making your own phenol red solution, add phenol red to water first.
Lessons preceding:
1. States of matter
2. Atomic structure and simple bonding between atoms in a molecule (e.g. water molecule)
3. Physical changes
Lessons following:
Visual and symbolic representations of chemical reactions showing reactants and new products
Vocabulary:
Chemical reaction, physical reaction, gas production, reactant, product, carbon dioxide gas, indicators, atoms,
atomic structure, molecules, bonds (breaking down and new formation of bonds result in rearrangement of atoms),
states of matter, chemical and physical properties, represent and representation, symbolic, substances
Steps of the Lesson
Learning Activities which lead to Model:
Teacher Questions for
Activity:
Key questions that show
progression from lower to higher
order thinking.
ENGAGE
1. Teacher reviews physical changes.
3. Questions to pose for
thought, but not discuss yet:
What are your observations?
What do you think has
Anticipated
Student
Responses,
Questions and
Errors:
What’s the black
stuff? Where does
the “toasty” smell
Teacher
Response to
Students and
Teacher
Intervention
Activities or
Strategies
2. T to Ss: “You know what a physical
change/physical reaction is. Now you
will observe an example of a chemical
reaction. There are many examples of
chemical reactions-this is just one
example”.
3. Bread Activity: Toast and burn six slices
of bread (one per group, in sealed baggie). Ss
observe and record their observations on
chart. Encourage Ss to include questions they
may have.
4. Teacher reviews observations (but does
not explain or engage in lengthy discussion).
5. Students create Initial Model (work
individually or in pairs)
Focus Question for Model:
What do you think is a chemical reaction?
Ss must include a written explanation. Tell
Ss “We would like you to answer this
without drawing a piece of toast. If you must
draw a piece of toast, it must be to clarify
your written explanation”.
happened?
You have been told this is a
chemical reaction. What do
you think makes it a “chemical
reaction?”
How is this different from a
physical reaction/change?
What questions do you have?
3.
Ss might say: black
color, new substance
which is powdery,
crumbly; there was
water/water vapor in
the baggie. The fresh
bread is no longer
there.
come from?
It’s a chemical
reaction because
the bread has
been
changed/burned.
You can’t get the
bread back.
5. Ss might list the following
indicators: black color/or color
change; water or water vapor
is formed or they might even
say that “something new is
formed”.
Instead of a list, Ss might
draw and label these
changes/indicators on a
drawing.
What is calcium
chloride?
EXPLORE
Chemical Reactions
Students will investigate and make direct
observations (on the same Observation
Chart), of two chemical reactions:
1) Calcium chloride and water
2) Calcium chloride, water, baking soda, phenol
red.
T tells Ss: “Today we will explore other
chemical reactions. Your careful observations
will help you better understand what a chemical
reaction is and how you can tell if one has
occurred!”
The original
substances are:
White, solid,
some are liquid,
phenol is red
Sequence of Lab Instruction
1. Review Safety precautions-goggles, gloves,
baggie inflation, clean up.
2) Lab-Ss do the first part of the reaction
(calcium chloride and water in baggie) and write
From Observation Chart:
a. What do the original
substances look like,
before combining them?
What do they look like
after combining them?
“After”
observations
include: gas
bubbles, heat, red
to yellow color
It’s a
chemical
compound
that is
commonly
used in
industry, such
as the pickle
industry.
observations on the observation chart
individually. Remind them to feel the bottom of
baggie to feel the heat!
3) Put materials aside!
4) Talk with partner and write down further
observations.
b.
c.
d.
e.
What observations did
you make?
Was there anything
surprising?
Do you see any new
substances?
What questions do you
have?
change.
The bubbles are
the new
substance.
What do you
think is inside
the bubbles?
It is carbon
dioxide gas,
just like the
gas in soda
cans.
5) Teacher processes the 1st reaction, going over
the students’ recorded observations. Make sure
they are observations and not procedures.
6). Ss do the second part of reaction: Add the
baking soda and phenol red. Seal baggie and
make observations. Again, feel bottom of baggie.
Repeat steps 3-4 above.
7. Teacher reviews the responses from the
Observation Chart. Students that may have
missed something can add it to their chart. (At
this point teacher does not yet explain what a
chemical reaction is.)
From bottom of Obs.
Chart:
What are the similarities
and differences between
the two investigations?
Ss might say that bubbles
contain O2 gas (instead
of CO2).
Both
investigations
involved heat, but
we added heat to
the first and in the
CaCl2 one the
heat came from
the reaction!
There is also
color change,
black in the first,
yellow in the
second.
The difference is
that the second
reaction produced
bubbles, and a
yellow color
change rather
than black.
T clarifies to Ss
that phenol red
works for CO2,
not O2. A color
change from red
to yellow
indicates the
presence of CO2.
EXPLAIN
A. Student Explanation
1. Student pairs return to their initial models and
revise the model based on the question:
“Based on your observations of the lab you
just did, now what do you think is a chemical
reaction?
2. Students Compare Their Revised to their
Initial Model:
Ss answer the following question on the back:
“What additions or changes, if any, did you
make to your model?”
3. Ss share out their models and the
additions/changes they made. As Ss share, T
asks: Do all chemical reactions involve the same
indicators? (Answer: no, some involve only one,
some involve many).
B. Teacher Explanation
1. Teacher summarizes student findings.
Definition:
A chemical reaction is a change that makes something new. The
new material produced always has different properties from the
starting material. The bonds holding the atoms together break
apart. The atoms then rearrange to form a new substance.
Clues or “indicators” that a chemical reaction has taken place
are:
a. new substance is formed with different properties
b. color change
c. temperature change (heat absorption or release
d. gas produced (bubbles; sound of bubbles)
d. odor
e. sound
f. light produced
The most important of these is “a new substance is formed, has
properties that are different from original reactants”.
2. Literacy Strategy
From Changes In Matter-Delta Science Content
Readers by Delta Education, pages 19-23.
a. Student groups are assigned a paragraph to
read together. They will follow a literacy
strategy that engages students in completing a
chart/poster with the following steps: See sample
chart.
Topic-What is the topic of the paragraph?
Questions-What questions do you have?
Predictions-What do you predict will happen
next?
Read the section assigned (paragraph)
Complete the Main Idea and details
Visual Notes
Answers to questions and Predictions
b. Student groups will present their posters to the
class. Teacher will mediate discussion and
2. Hopefully Ss added
the following indicators
to model: heat release or
heat absorption, new
substance is formed such
as gas bubbles, color
change. The new
substance is very
different from original
substances.
B. Again, review the fact that
some chemical reactions
involve one indicator while
others involve several.
However, the key indicator is
the formation of a new
substance, which has
properties different from
original reactants.
B1. Ss will most likely not
come up with “the bonds
holding the atoms break
apart...” as this idea has not
been presented. The literacy
activity will present this idea
through the reading selection.
See Explain #5.
summarize findings at the end of the sharing.
3. Based on the reading group presentations, and
teacher summary/discussion, students will
revise model again for the final time.
ELABORATE
Students will apply their learning to hypothesize
examples of chemical reactions in their home
and school communities. The examples may
include favorite food items prepared at home, a
sibling’s new hair color or hair dye, a tattoo,
mom’s favorite perfume, etc. Students will
select an example from the list to research.
Students will synthesize their research, revised
model of a chemical reaction, and notes to
determine if the example is the result of a
chemical reaction.
2. In their science journals, students will use
illustrations, symbols, and writing to explain in
detail if the example is the result of a chemical
reaction and orally present their findings.
Teacher questions will be
generated during the oral
presentations. They
should serve to check
understanding, solidify
ideas, and clarify
misconceptions.)
Responses will
2a. Describe the
vary.
substances before the
reaction? (States of
matter, physical and
chemical properties, etc.)
2b. What caused the
reaction?
2c. What happened when
the substances were
combined, separated, etc?
Or what did you observe
when the substances
were combined,
separated, etc.?
2d. Does your evidence
support a chemical
reaction or physical
reaction?
2e. In your example of a
chemical reaction, how
do you know that you
observed a rearrangement
of atoms?
2f. In your chemical
reaction, what new
substance was created?
2g. In your example of a
physical reaction, how do
you know that you did
not observe a
rearrangement in the
atoms?
2h. In your physical
reaction, if you did not
observe the formation of
a new substance, then
Clarify as
needed.
Allow
students to
reference their
model and
notes for
clarification.
what change did you
observe?
EVALUATE
Give Ss list of 3 scenarios. Have them choose 1
out of 3 examples of a reaction. Students will be
expected to reference their revised model of a
chemical reaction and notes and utilize them to
write a short essay to explain why the reaction is
a chemical reaction. Students will be expected to
give visual, symbolic, and written details to
support their reasoning.
1. An electric current flows through water
causing the water molecules to break up into
hydrogen gas and oxygen gas.
water  oxygen + hydrogen
2. A glass of water is placed in a freezer. After
several minutes, the liquid water freezes and
becomes ice.
water (liquid matter) = ice (solid matter)
3. Sodium, a metal, is combined with chlorine, a
harmful green gas. The atoms in each of the two
substances rearrange to form a new substance
sodium chloride, table salt.
sodium + chlorine  sodium chloride (table salt)
Why is the example you
chose a chemical
reaction?
We know a
chemical reaction
has occurred
because a new
substance is
formed.