Read the bottom of the curve. Each small line is 1 mL.
123 beatsX exploded layersR reset viewC cinematic/ hide UIdrag: orbit · right-drag: pan · wheel: zoom · click object: drop itdrag: orbit · pinch: zoom · 2 fingers: pan · tap object
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For teachers
Grade 6 · about 40 minutes · one device per 1–2 students.
Objectives
Find the volume of a right rectangular prism by packing it with unit cubes, including ½-cm cubes for fractional edges.
Show that packing gives the same answer as V = L × W × H (and V = B × h).
Explain that 1 cm³ = 1 mL.
Measure the volume of an irregular solid by water displacement, reading a graduated cylinder at eye level, at the bottom of the meniscus.
Standards
CCSS.MATH.CONTENT.6.G.A.2 Volume of right rectangular prisms with fractional edge lengths, by packing with unit-fraction cubes and by V = l w h, V = b h.
Review: 5.MD.C.3, 5.MD.C.4, 5.MD.C.5 (volume as packing with unit cubes).
NGSS practices: Using Mathematics and Computational Thinking; Planning and Carrying Out Investigations (lab measurement).
Suggested flow (~40 min)
Warm-up (5 min). Hold up a box and a rock. "Which takes up more space? How could we know?"
Beat 1 (12 min). Build 4 × 3 × 2. Count layers with X. Then try 2.5 × 3 × 4. Ask why the lab switches to ½-cm cubes. Confirm 240 ÷ 8 = 30.
Beat 2 (5 min). Pour the box. Link cm³ to mL. Try a box over 100 cm³ and discuss the overflow.
Beat 3 (12 min). Pairs change the start level, drop each object, and read the final level at eye level. Record start, final, and volume in a table.
Check yourself (6 min). Use the five questions as an exit ticket.
Vocabulary
Volume
How much space something takes up.
Cubic centimeter (cm³)
The space inside a cube that is 1 cm on each side.
Milliliter (mL)
A unit for liquid volume. 1 mL = 1 cm³.
Meniscus
The curve at the top of water in a narrow tube. Read its bottom.
Displacement
When an object sinks, it pushes water out of its way. The water rises by the object's volume.
Common misconceptions
Area vs. volume. Students write cm² for volume. Ask: "Are we counting squares or cubes?"
Counting only what you see. Students count visible faces. Exploded layers show the hidden cubes.
Fractions break the formula. Some think ½-cm edges cannot be packed. Show 8 half-cubes = 1 cm³.
mL and cm³ are different amounts. They are the same amount, with different names.
Reading the top of the curve, or from above. This gives a reading that is too high. Get eye level with the flat middle.
Heavier means more water moves. For an object that sinks, the rise depends on its volume, not its weight.
Forgetting to subtract. The final reading is not the volume. Volume = final − start.
Object volumes in this lab (answer key)
Marble 5 cm³ · Metal bolt 7 cm³ · Rock 12 cm³ · Toy dinosaur 18 cm³. The water rises by exactly these amounts.
Keys
123 beats · X exploded layers · R reset view · C cinematic · / hide UI (for projecting).