Measuring the Loudness of Sound

Objectives:

• Students will be able to describe the factors that affect the volume of sounds.

• Students will be able to name the instrument that measures the volume of sounds.

• Students will understand that sound is measured in decibels.

• Students will be able to compare the decibel levels of different sounds.

• Students will be able to describe what an audiologist does to evaluate hearing.

Suggested Grades:

5th Grade - 6th Grade - 7th Grade

Lesson Procedure:

Print the reading comprehension worksheet passage and questions (see below).

Students should read the passage silently, then answer the questions. Teachers may also use the text as part of a classroom lesson plan.

Lesson Excerpt:

Sounds are created when molecules in the air vibrate to create sound waves. The distance that these particles in the air travel when they vibrate back and forth depends on the amount of energy used to create them. Waves that carry more energy produce louder sounds. These sound waves can be measured by an oscilloscope. The oscilloscope records the sounds as wiggly lines like the examples below. The sound wave on the left has higher waves, so it is a louder sound.

Another word for the loudness or softness of a sound is volume. You can see how energy and volume are related when you try to make a sound yourself. You need more energy to yell than you do to whisper. If you knock on a door and no one hears you, you might try knocking harder so the sound will be louder.

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