# Pendulum Snake

### Source Institutions

The Exploratorium

In this physics activity, learners assemble and/or investigate a pendulum "snake." Several large steel hex-nuts are suspended on strings of successively increasing length to form a series of pendulums with successively increasing periods. When all pendulums are released simultaneously with the same amplitude, they gradually form an undulating snake-like pattern, and then undergo further changes which are fascinating from both a visual and mathematical perspective.

### Quick Guide

Learning Time:

Estimated Materials Cost:
\$10 - \$20 per group of students

Age Range:
Ages 8 - 18

Resource Types:
Activity, Demonstration

Language:
English

### Materials List (per group of students)

• 10 3/4 in hex nuts (or 1/2 in)
• 8 m braided string
• 1/2 in Schedule 40 PVC pipe pieces: 58 cm long piece, drilled; 2 45cm long pieces; 4 25cm long pieces; 2 elbow joints; 2 T joints; 4 end caps
• 10 paper clips
• tapestry needle (or paper clip)
• 21 in long piece of 1 in x 4 in
• PVC cutters
• drill and 1/8 in drill bit
• masking tape
• scissors
• metric measuring tape
• pencil
• a method for calculating the desired lengths (or a list of lengths already calculated – the list is included in this write up)
• sheet metal screws, #6, 1/2 in long, pan head, Phillips

### Subjects

• Mathematics
• Algebra
• Equations and Inequalities
• Patterns
• Variables and Expressions
• Measurement
• Rate
• Number and Operations
• Problem Solving
• Representation
• Physical Sciences
• Energy
• Potential and Kinetic Energy
• Motion and Forces
• Gravity
• Center of Gravity
• The Nature of Science
• The Scientific Process
• Conducting Investigations

• Toys

### Audience

• see
• touch

#### Learning styles supported:

• Involves teamwork and communication skills
• Involves hands-on or lab activities

### Other

• Free access

#### By:

• Rathjen, Don; Lambertson, Lori

#### Rights:

• All Rights Reserved, Exploratorium, ©2005