Math:
CCSS.MATH.CONTENT.5.MD.C.3
Recognize volume as an attribute of solid figures and understand concepts of volume measurement.
CCSS.MATH.CONTENT.5.MD.C.3.A
A cube with side length 1 unit, called a "unit cube," is said to have "one cubic unit" of volume, and can be used to measure volume.
CCSS.MATH.CONTENT.5.MD.C.3.B
A solid figure which can be packed without gaps or overlaps using n unit cubes is said to have a volume of n cubic units.
ELA:
English Language Arts/Reading Standards link
Social Studies:
Science:
S5P1: Students will verify that an object is the sum of its parts.
S5P2. Students will explain the difference between a physical change and a chemical change.