LF-07 · TEACHER LESSON PLAN

Density column

Measure equal liquid volumes, then test where dry objects settle

ChemistryGrades 5–950 minHazard low; spills and non-food lab samplesNGSS MS-PS1-1

01 //

Driving question

START THE LESSON WITH THISHow do measured liquid density and mixing behavior help explain where a dry object settles?

02 //

Learning objectives

Students measure the mass of equal 30 mL volumes and calculate each household liquid's density in g/mL.
Students observe whether the selected liquid phases remain separate after a measured, careful pour.
Students predict where each dry test object may settle, then compare its observed position with the measured column.

03 //

Standards

Dimension	Alignment
Performance expectation	MS-PS1-1Develop models to describe the atomic composition of simple molecules and extended structures. (Partial alignment: this is the performance expectation the lab lists, but the activity investigates a physical property of matter (liquid and object density) rather than building atomic models.)
Practices	SEP 6Construct explanations.
Core idea	PS1.AEach pure substance has characteristic physical and chemical properties (for any bulk quantity under given conditions) that can be used to identify it.
Crosscutting	Cause and effectCause and effect relationships are routinely identified, tested, and used to explain change.

NGSS performance expectation, core idea and crosscutting concept wording are based on the published NGSS text. The listed performance expectation has only a limited connection to this density investigation.

03A //

State standards crosswalk

Use the row as a planning crosswalk, then confirm local district pacing and grade placement. “Partial” labels describe a skill connection, not full mastery of the complete standard.

State	Verified standard	How this lesson aligns	Official source
California	CA NGSS 5-PS1-3	Limited connection only: students observe and record material properties, but this standard's assessment boundary explicitly excludes density as an identifying property. Do not count this activity as full alignment.	Open standard ↗
Texas	Science.6.6(D)	Direct topic match: students measure equal liquid volumes, calculate density from net mass, and compare relative positions; the object column remains qualitative.	Open standard ↗
Florida	SC.8.P.8.4	Direct topic match: students compare measurable physical properties by calculating liquid density and observing objects in the column; the lesson does not cover every part of the standard.	Open standard ↗
New York	NYSSLS 5-PS1-3	Limited connection only: students observe and record properties, but the standard's assessment boundary explicitly excludes density. Treat density as an extension beyond this performance expectation.	Open standard ↗
Pennsylvania	STEELS 3.2.6-8.A	Limited practice connection: students model a material property, while this expectation focuses on atomic-composition models. The column does not demonstrate the full expectation.	Open standard ↗

04 //

Materials and prep timeline

PER GROUP

One clear plastic column (about 500 mL) and stable tray
About 60 mL each of one syrup, dish soap, water and cooking oil
Balance, 30 mL graduated measure, and one clean massing cup
One drop of food coloring for the water
One cork, grape, plastic bead and steel washer
One spoon or pipette, labels and paper towels
One observation sheet per student

TEACHER ONLY

For 20, 25 or 30 students, stage 5, 7 or 8 complete group kits; print one student sheet per student.
Place each plastic column on a tray and check product ingredients and allergies before setup.
Demonstrate taring the cup or subtracting its empty mass; use 30 mL for every density reading.
Show how to pour slowly, then record mixing or emulsification instead of promising four stable bands.
Direct disposal of mixed liquids according to local guidance; do not pour oil down the drain.

CLASS-SIZE KIT PLANNER

One per-group kit contains every item in the team materials list above. Groups are balanced around the listed 3–4 students target.

Students	Groups	Per-group kits	Student sheets	Suggested group split
20	5	5 complete kits	20 copies	5 groups of 4
25	7	7 complete kits	25 copies	4 groups of 4 and 3 groups of 3
30	8	8 complete kits	30 copies	6 groups of 4 and 2 groups of 3

0–5 MINPredict the densities and positions

Predict the measured order of the liquids and where each dry object may settle; record predictions before testing.

5–15 MINMeasure equal liquid volumes

Tare the same clean cup, measure 30 mL of each product, record net mass, and calculate density as g/mL.

15–25 MINBuild and observe the column

Pour from greatest measured density to least. Wait five minutes and record whether each phase stays separate, blurs or mixes.

25–37 MINTest dry objects

Lower each object gently; record its position after 30 seconds and note any bubbles or mixing.

37–50 MINExplain and clean

Compare measured values with observed positions, discuss miscibility and model limits, then follow teacher disposal directions.

04A //

Lab figures and data visuals

Reviewed article images support the lesson flow. Use the tables and student sheet to record actual observations; pictured patterns are not target results.

Oil sits above more-dense water in separate layers; labels explain that oil and water do not mix and soap can disrupt a column. — **Density sets order; miscibility affects separation.**Oil and water commonly form separate phases; dish soap can mix with water or emulsify oil, so not every density column keeps sharp layers.

A clear density column shows vegetable oil, colored water, dish soap and honey in separate layers, with small objects illustrating possible positions. — **Objects move through layers according to relative density.**This is an illustrative arrangement; household products can mix and objects do not always stop at a sharp boundary.

An object sinks through a less-dense upper liquid and rests at the boundary with a more-dense lower liquid. — **An object stops at the boundary that supports it.**The object is denser than the liquid above but less dense than the liquid below, so it sinks through one and floats on the other.

04B //

Printable shopping list

TEACHER PREP · Density column

Shopping and staging checklist

Multiply the per-group kit contents by the class-size planner. The teacher section includes teacher-provided materials and setup or safety notes.

PER-GROUP KITS

One clear plastic column (about 500 mL) and stable tray
About 60 mL each of one syrup, dish soap, water and cooking oil
Balance, 30 mL graduated measure, and one clean massing cup
One drop of food coloring for the water
One cork, grape, plastic bead and steel washer
One spoon or pipette, labels and paper towels
One observation sheet per student

TEACHER-PROVIDED MATERIALS + SETUP RULES

For 20, 25 or 30 students, stage 5, 7 or 8 complete group kits; print one student sheet per student.
Place each plastic column on a tray and check product ingredients and allergies before setup.
Demonstrate taring the cup or subtracting its empty mass; use 30 mL for every density reading.
Show how to pour slowly, then record mixing or emulsification instead of promising four stable bands.
Direct disposal of mixed liquids according to local guidance; do not pour oil down the drain.

QUANTITIES BY CLASS SIZE

Material	Per group kit	20 students	25 students	30 students
Clear plastic column on tray	1	5	7	8
Each liquid, syrup / soap / water / oil	60 mL	300 mL	420 mL	480 mL
Balance and 30 mL graduated measure	1 each	5 each	7 each	8 each
Food coloring	1 drop	5 drops	7 drops	8 drops
Cork, grape, plastic bead and steel washer	1 of each	5 of each	7 of each	8 of each
Spoon or pipette, tray and towel	1 of each	5 of each	7 of each	8 of each
Labels	1 set	5 sets	7 sets	8 sets
Observation sheets	1 per student	20	25	30

Prepare 5 kits for 20 · 7 kits for 25 · 8 kits for 30 students.

05 //

Lesson flow

Minutes	What happens
0–5	Engage Ask how both density and mixing behavior may affect the column. Record density and object-position predictions.
5–15	Explore Measure equal 30 mL samples, record net mass and calculate each liquid's density.
15–25	Pour from greatest measured density to least, wait five minutes and record which phases stay separate or mix.
25–37	Explain Test the cork, grape, plastic bead and steel washer gently. Record each observed position after 30 seconds and compare it with the measured liquid values.
37–50	Evaluate Explain the result using density and miscibility; include one product or method limitation. Do not taste the column; dispose of oil as directed.

06 //

Discussion questions

1. How can an object stop at a boundary?

SAMPLE ANSWERIt can be denser than the liquid above but less dense than the liquid below, so it sinks through one layer and is supported by the next.

2. Why record the actual liquid order rather than assume a fixed recipe?

SAMPLE ANSWERDish soap, oil and syrup formulations vary, and temperature or mixing changes boundaries. Density helps predict order, but miscibility controls whether phases remain distinct; the observed column is the evidence for this setup.

3. Why dry each object before adding it?

SAMPLE ANSWERSurface water or an air bubble can change how the object enters or appears to settle, making the layer observation less reliable.

4. Does this column give an exact density for each object?

SAMPLE ANSWERNo. It gives a qualitative comparison. The liquid samples get approximate density values from mass divided by equal volume; an object boundary only brackets its average density under that particular setup.

07 //

Common misconceptions

STUDENTS OFTEN SAY“The top liquid is always oil and the bottom is always syrup.”

BETTER IDEAProducts vary; record the actual order after the column settles instead of relying on a memorized recipe.

STUDENTS OFTEN SAY“A heavy object must sink to the bottom.”

BETTER IDEAPosition depends on average density, which relates mass to volume, not total weight alone.

STUDENTS OFTEN SAY“A swirl is another stable layer.”

BETTER IDEATemporary swirls can come from turbulence. Let the column settle and identify stable boundaries before testing objects.

08 //

Differentiation

SUPPORT

Provide a four-color key and layer labels that students can place beside the clear cylinder.
Model a top-to-bottom sketch before adding any objects.
Offer the frame: “The ___ settled at ___, between ___ and ___; I predicted ___.”

EXTEND

Measure equal liquid volumes on a balance and calculate mass per volume to estimate density order.
Compare one object in each layer and use its resting boundary to bracket its average density.
Repeat with a different brand of dish soap or oil and explain why the layer order may shift.

09 //

Assessment rubric

Criterion	Beginning	Developing	Secure
Layer order	Does not record the liquid order.	Records some layers but omits top/bottom or boundaries.	Labels the observed settled layers from top to bottom.
Prediction and observation	Leaves object predictions or outcomes blank.	Records predictions and outcomes but does not compare them.	Records each object’s predicted and actual resting layer and marks the match accurately.
Density explanation	Explains only by object weight or size.	Names density without comparing the surrounding layers.	Uses relative density of object and adjacent liquids to explain the resting position.
Model limits and care	Treats the layer order as exact for every product or tastes a sample.	Names one setup limit or safety rule.	Recognizes product/mixing variation and handles the non-food mixed column safely.

10 //

Vocabulary

Density – Mass divided by volume; a measure of how much matter occupies a given space.
Layer – A distinct region of liquid in the settled column.
Boundary – The surface between two neighboring liquid layers.

Average density – The mass of an entire object divided by its total volume, including enclosed air.
Displace – To move liquid out of the way when an object enters it.
Prediction – A testable statement about what may happen before collecting the result.

11 //

Safety, cleanup and troubleshooting

BEFORE STUDENTS TOUCH ANYTHING

Even if the starting liquids are kitchen products, the mixed column is a lab sample: do not drink or taste it. Check ingredients for allergies before setup.
Use a stable, unchipped container on a tray. Wipe spills promptly; syrup and oil can make floors slippery.
Lower dry objects gently and keep the cylinder away from the table edge. Follow teacher directions for disposal; do not pour oil down the sink.

Troubleshooting: If boundaries look blurred, stop adding liquids, keep the cylinder still and wait for settling. If an object carries surface water or trapped air, remove it, dry it and retest only if the column remains clear. Clean oil or syrup spills promptly and do not taste any mixture.