Product Details
Two layers of beads are suspended in the middle of a bottle. Give the bottle a shake and the beads move to opposite ends. The beads then slowly move back to the starting position. How does this happen? Two liquid layers of differing densities create an interface in the middle of the bottle. When the bottle is shaken, a homogenous liquid mixture of uniform density is formed and the apparent densities of the beads can be observed. The attention-getting display is sure to generate questions and gives you a great lead-in for lessons on density, polarity and solubility. Teacher Demonstration Notes and student handouts are included. The bottle may be reused for years.
Concepts: Density, non-polar vs. polar, solutions, immiscibility
Time Required: 10 minutes
Special thanks and acknowledgment to Lynn Higgins, ACS Polymer, Ambassador, MO, in recognition of her creative activity idea that this demonstration is based on.
Specifications
Materials Included in Kit:
Isopropyl alcohol, reagent, 500 mL
Sodium chloride, 100 g
Plastic soda bottle, 1 L
Pony bead, green, 9 mm, 50 g
Ultraviolet detection beads, 50 g
Correlation to Next Generation Science Standards (NGSS)†
Science & Engineering Practices
Developing and using models
Obtaining, evaluation, and communicating information
Analyzing and interpreting data
Disciplinary Core Ideas
MS-PS1.A: Structure and Properties of Matter
HS-PS1.A: Structure and Properties of Matter
HS-PS2.B: Types of Interactions
Crosscutting Concepts
Patterns
Structure and function
Cause and effect
Systems and system models
Performance Expectations
MS-PS1-1. Develop models to describe the atomic composition of simple molecules and extended structures.
MS-PS1-3. Gather and make sense of information to describe that synthetic materials come from natural resources and impact society.
HS-PS1-1. Use the periodic table as a model to predict the relative properties of elements based on the patterns of electrons in the outermost energy level of atoms.
HS-PS2-6. Communicate scientific and technical information about why the molecular-level structure is important in the functioning of designed materials.