Lesson 6 — 2E

• Science
• Middelbare school
• havo
• Leerjaar 2

5.7 Echoes

This lesson

•  Recap
• Echoes
• Practice exercises
• Time to study

Learning goals

• Recap — Explain the mach system, how instruments get their distinct sound and how to calculate the speed of sound.
• Explain in your own words how echoes work.
• Describe how echo location works.
• Be able to do calculations involving echoes and echo location

Recap

The distinct sound of 

musical instruments

Main frequency 

(the fundamental) 

with other frequencies mixed in (harmonics)

The distinctive sound that an instrument makes is called its timbre

The mach system

How does it work?

What is mach 1

What is mach 2

What is mach 3?

Mach 1, Mach 2, Mach 3

• Mach 1: traveling at 343 meters per seconds
  
• Mach 2: traveling at 686 meters per seconds
  
• Mach 3: 1029 meters per seconds
  
• The fastest skydiverer, Felix Baumgartner, traveled at mach 1.1, how fast did he fall?
  

5.6 Making simple calculations

Speed=​time​​distance​​

v=​t​​d​​

• v: speed (m/s)
  
• d: distance (m)
  
• t: time (s)
  

5.7 Echoes

Echo location

Calculation exercise

A man has set out the find the deepest well in the world. Once he found it he clapped his hands above it. He timed how long it took before he heard an echo. It took 71.4 seconds. The speed of sound in air is 330 m/s. 

Calculate how deep the well is.

Worksheet waves

Learning goals

• Recap —Explain the mach system, how instruments get their distinct sound and how to calculate the speed of sound.
• Explain in your own words how echoes work.
• Describe how echo location works.
• Be able to do calculations involving echoes and echo location