Lesson 1: Investigating Properties – Why Do Some Materials Allow Electricity to Flow?

• Why do some materials allow electricity to flow while others do not?
• What observable patterns exist among conductive materials?
• Is conductivity related to other physical properties?
• Can liquids conduct electricity? Under what conditions?
• What counts as evidence in a physical investigation?

Conductor
Insulator
Electric current
Closed circuit
Open circuit
Voltage
Resistance
Property
Variable
Control
Evidence
Pattern

HS PS2-6
Communicate scientific and technical information about why molecular-level structure is important in the functioning of designed materials.

Science and Engineering Practices:
Planning and Carrying Out Investigations
Analyzing and Interpreting Data
Constructing Explanations

Crosscutting Concepts:
Structure and Function
Patterns
Cause and Effect

• Interpreting experimental setup
• Identifying controlled variables
• Analyzing patterns in collected data
• Writing evidence-based explanations
• Distinguishing observation from inference

Students practice scientific reasoning and CER writing aligned with standardized science assessment expectations.

Day 1 – Introduction to Simple Circuits

Students are introduced to a low-voltage battery pack with exposed leads and a buzzer or light indicator.

Teacher demonstrates:

Open circuit versus closed circuit
How completing the circuit activates the buzzer

Students test basic materials:

Metal paperclip
Plastic
Wood
Graphite pencil lead

Students are not given a list of conductors. They are told:

“Test anything safe that is not electronic.”

Purpose:
Establish conductivity as observable phenomenon.

DOK: 2 – Follow procedure and identify outcomes.

Day 2-3 – Open Investigation

Students test a variety of materials, including:

Different metals
Plastics
Fabrics
Liquids

Students test water both before and after salt is dissolved.

They record:

Material tested
Did the buzzer activate?
Was the signal strong or weak?
Other observed properties such as hardness or flexibility

Students begin identifying patterns:

Most metals conduct.
Pure water does not conduct well.
Saltwater conducts.

Purpose:
Encourage open inquiry and pattern recognition.

DOK: 2 – Identify patterns from collected data.

Day 4-5 – Evidence-Based Explanation

Students analyze class-wide data.

They respond to prompts:

What properties do conductive materials share?
Why might saltwater conduct but pure water does not?
Is conductivity related to hardness or flexibility?

Students construct a CER response explaining:

Which materials conduct and why, using evidence from their testing.

Teacher begins introducing the idea that structure at smaller scales may explain observed behavior, preparing for Segment 2.

Purpose:
Transition from observation to explanatory reasoning.

DOK: 3 – Construct evidence-based explanation.

Students connect findings to:

Why wires are copper but coated in rubber
Why electronics must stay dry
Why salt on roads affects car components
Why graphite in pencils conducts

Students recognize that material selection in engineering is purposeful, not accidental.

• Electricity is “stored” inside metal.
• All metals conduct equally well.
• Heavier materials conduct better.
• Thickness determines conductivity.
• Water itself conducts electricity rather than dissolved ions.
• Hardness determines conductivity.

Teacher pushes students to separate correlation from causation and avoid oversimplified explanations.

• Provide structured data tables for students who need organizational support.
• Offer guided investigation checklists.
• Allow partner testing for safety and collaborative reasoning.
• Provide sentence stems for CER writing.
• Extension: Have advanced students rank conductivity strength or test additional variables.

Formative Assessments:

• Completed investigation data table
• Class pattern identification discussion
• CER paragraph explaining conductivity

Exit Ticket Prompt:

Explain why saltwater conducted electricity but pure water did not. Use evidence from your investigation.

Evaluation Criteria:

Accuracy of observation
Clear identification of pattern
Appropriate use of evidence
Logical explanation of cause