6.3.3
Uses of Sound Waves
Sound is a Wave
Sound is a Wave
Sound is a wave. Because of this, it can be:
Reflected
Reflected
- Echoes are an example of sound waves being reflected.
Ultrasound Waves
Ultrasound Waves
When ultrasound waves meet a boundary between two different materials, some are reflected. We can work out how far away a boundary is based on how long it takes for reflections to reach a detector. We can use ultrasound waves for both medical and industrial imaging.
Medicine
Medicine
- Doctors use ultrasound to perform scans of a developing foetus.
- Ultrasound waves can pass through the body.
- Whenever they reach a boundary between two different materials, some will be reflected. We can detect the reflected waves.
- A computer processes the timing and distribution of these waves. The computer uses these to produce a video image of the foetus.
Industry
Industry
- We can use ultrasound to find flaws in objects or materials (e.g. pipes or wood).
- When ultrasound waves enter a material, they will normally be reflected by the far side of the material.
- If there is a flaw (e.g. a crack), the waves will be reflected sooner. This tells us that there is a problem.
Water depth
Water depth
- We can use echo sounding to detect objects in deep water and also to measure water depth.
- We send an ultrasound pulse into the water. When this pulse hits any surface, it is reflected back.
- We can work out the distance travelled by the sound wave by recording the time between us sending the pulse and detecting the reflection.
Training dogs
Training dogs
- Ultrasound has a frequency above 20,000Hz. Humans cannot hear sounds with frequencies this high, but other animals can.
- Dog whistles have frequencies above 20,000Hz. This is why humans cannot hear them.
Earthquakes
Earthquakes
Seismic waves are waves which travel through the Earth. Earthquakes produce two types of seismic waves:
P-waves (primary)
P-waves (primary)
- These are longitudinal, seismic waves.
- P-waves travel at different speeds through solids and liquids.
S-waves (secondary)
S-waves (secondary)
- These are transverse, seismic waves.
- S-waves cannot travel through liquids (only through solids).
Uses of seismic waves
Uses of seismic waves
- Seismic waves cannot travel through all parts of the earth because the earth is made up of different materials.
- Scientists have used this principle to work out the different materials that the earth is made up of.
- By detecting seismic waves from Earthquakes, scientists have worked out that the Earth has a solid core surrounded by a liquid outer core.
- A mantle of changing density surrounds the Earth’s core. This mantle causes the refraction of the seismic waves.
1Energy
1.1Energy Changes
1.1.1Energy Stores
1.1.2Calculating Changes in Energy
1.1.3Changes in Kinetic Energy - Calculations
1.1.4Changes in GPE - Calculations
1.1.5Changes in EPE - Calculations
1.1.6Energy Transfers
1.1.7Mechanical Work Done
1.1.8Mechanical Work - Calculations
1.1.9Electrical Work Done
1.1.10Electrical Work Done- Calculations
1.2Energy Losses & Efficiency
2Electricity
2.1Electric Charge
2.2Resistance & Electrical Work
2.3Electric Circuits
2.4Electricity in Homes
2.5Static Electricity
3Particle Model of Matter
3.1States of Matter
3.2Heat
4Atoms & Radiation
4.1Atoms
4.2Radiation
4.2.1Radioactive Decay
4.2.2Radioactive Decay 2
4.2.3Types of Radioactive Emission
4.2.4Fission & Fusion
4.2.5Radioactive Decay Equations
4.2.6Radio. decay equations - Calculations
4.2.7Half Lives & Ionising Radiation
4.2.8Half Life - Calculations
4.2.9Uses & Dangers of Radiation
4.2.10Uses & Dangers of Radiation 2
4.2.11End of Topic Test - Atoms & Radiation
4.2.12Grade 9 - Radiation
4.2.13Exam-Style Questions - Radioactive Decay
5Forces
5.1Basics of Motion
5.2Forces
5.2.1Gravity
5.2.2Gravity - Calculations
5.2.3Resultant Forces
5.2.4Newton Second Law - Calculations
5.2.5Force Diagrams
5.2.6Free Body Diagrams - Calculations
5.2.7Stretching a Spring
5.2.8Hooke's Law
5.2.9Hooke's Law - Calculations
5.2.10Elastic Potential Energy
5.2.11Elastic Potential - Calculations
5.2.12Exam-Style Questions - Elastic Potential Energy
5.3Effects of Forces
6Waves
6.1Wave Basics
6.2Waves at a Boundary
6.3Sound Waves
6.4Electromagnetic Waves
7Magnetism
7.1Magnetism Basics
7.2Electromagnetism
Jump to other topics
1Energy
1.1Energy Changes
1.1.1Energy Stores
1.1.2Calculating Changes in Energy
1.1.3Changes in Kinetic Energy - Calculations
1.1.4Changes in GPE - Calculations
1.1.5Changes in EPE - Calculations
1.1.6Energy Transfers
1.1.7Mechanical Work Done
1.1.8Mechanical Work - Calculations
1.1.9Electrical Work Done
1.1.10Electrical Work Done- Calculations
1.2Energy Losses & Efficiency
2Electricity
2.1Electric Charge
2.2Resistance & Electrical Work
2.3Electric Circuits
2.4Electricity in Homes
2.5Static Electricity
3Particle Model of Matter
3.1States of Matter
3.2Heat
4Atoms & Radiation
4.1Atoms
4.2Radiation
4.2.1Radioactive Decay
4.2.2Radioactive Decay 2
4.2.3Types of Radioactive Emission
4.2.4Fission & Fusion
4.2.5Radioactive Decay Equations
4.2.6Radio. decay equations - Calculations
4.2.7Half Lives & Ionising Radiation
4.2.8Half Life - Calculations
4.2.9Uses & Dangers of Radiation
4.2.10Uses & Dangers of Radiation 2
4.2.11End of Topic Test - Atoms & Radiation
4.2.12Grade 9 - Radiation
4.2.13Exam-Style Questions - Radioactive Decay
5Forces
5.1Basics of Motion
5.2Forces
5.2.1Gravity
5.2.2Gravity - Calculations
5.2.3Resultant Forces
5.2.4Newton Second Law - Calculations
5.2.5Force Diagrams
5.2.6Free Body Diagrams - Calculations
5.2.7Stretching a Spring
5.2.8Hooke's Law
5.2.9Hooke's Law - Calculations
5.2.10Elastic Potential Energy
5.2.11Elastic Potential - Calculations
5.2.12Exam-Style Questions - Elastic Potential Energy
5.3Effects of Forces
6Waves
6.1Wave Basics
6.2Waves at a Boundary
6.3Sound Waves
6.4Electromagnetic Waves
7Magnetism
7.1Magnetism Basics
7.2Electromagnetism
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