Physics of SoundInvestigation 2, Part 3

Tension and Pitch

Materials

Student sheet no. 11 called The Minigutbucket Student sheet no. 12 called The FOSS-ulele Large plastic bags Small nail Scissors Metric tape 2 Plastic cups 50 cm string 3 large paper clips Pencil 250 cm string Masking tape

Minigutbucket (for teacher)

Insert string through hole in plastic cup.

Tie a knot at the end of the string.Tie the opposite end of the string

around a chair or table leg.

FOSS-ulele (for teacher)

Place a plastic cup upside down on a table.

Tie one end of the string to a table leg.

Feed the string through the plastic cup.

Tie a pencil to the other end of the string.

Introduction

What is tension? (A force pulling on an object in opposite directions.)

How does tension affect pitch?

Will find out by exploring 2 instruments.

Instruments

5 minutes to explore

Minigutbucket Demonstrate how attaches to a table leg. Show how to apply tension to the string by pulling

gently but firmly on the cup.

FOSS-ulele Demonstrate how to use the paper clip to affix the

string to a table let, bring the string across the cup on top of the table, and use the pencil like a handle to apply tension to the string.

Student sheets

Distribute

Read instructions

Record observations

Describe the methods used to change the pitch.

How did you change the tension of the strings on the 2 instruments?

What happened to the pitch of the sound produced by the string as you changed the tension o the strings?

Review

Tension – force applied to an object trying to pull it apart

What happens t the pitch when the tension on a sound source changes? (The greater the tension on a sound source, the higher the pitch.)

Science Story – Scoping out Sound

The End!!!