Sand Castles
Phenomenon:
Wet sand sticks together and can be sculpted into a sand castle.
Student Task:
Construct an explanation based on evidence for what causes wet sand to stick together when you're building a sand castle.
Model
Students develop a model to describe the density of particles in solids, liquids, and gases.
Investigate
Students plan and carry out an investigation to 1) test the cohesive and adhesive properties of liquid water, and 2) test the proportion of water and sand needed to build a sand castle.
Obtain Information
Students read to obtain information about the forces of attraction between water molecules.
Analyze Data
N/A
Explanation:
Wet sand sticks together because...
Application:
Land slides
NGSS Standard:
MS-PS1-1 Develop models to describe the atomic composition of simple molecules and extended structures.
[Clarification Statement: Emphasis is on developing models of molecules that vary in complexity.]
Utah SEEd Standard:
6.4.3 Develop a model to show that molecules are made of different kinds, proportions and quantities of atoms.
[Emphasize understanding that certain combinations of atoms form specific molecules.]
Recommended Teaching Sequence:
Day 1:
Plan and carry out an investigation to determine the proportion of sand and water needed to build a sand castle.
Observe how the properties of dry sand change at different scales.
Day 2:
Argue from evidence to classify sand as a solid or a liquid (patterns).
Develop and use a model to describe the differences in density (quantity per volume) between a solid, a liquid, and a gas.
Plan an investigation to compare the properties of water and other liquid matter.
Day 3:
Carry out an investigation to compare the properties of water and other liquid matter.
Day 4:
Read to obtain information about the structure of water molecules and the forces of attraction between them.
Construct a written explanation based on evidence for what causes wet sand to stick together when you're building a sand castle.
Formative Assessment:
Use what students have written in their science notebooks as a formative assessment, including recorded observations of the properties of sand and water, data collected from the investigations, and the written explanation for the phenomenon of sand castles.
Do students understand that the structure of atoms and molecules influence the properties of materials? Do students understand that different materials with different properties are suited to different purposes?
Lesson Contributor:
April Mitchell, Science Coach, Salt Lake City School District