Using Waves to Explore Structures
We can use waves to explore the structures of materials.
We look at differences in velocity, absorption and reflection between different types of waves in solids and liquids to provide information on the structure of a material and also to detect what is inside a material.
A good example of this is the use of seismic waves to study the internal structure of the Earth.
Velocity of Waves:
Types of Waves:Different types of waves (e.g., longitudinal waves, transverse waves, sound waves) travel at different speeds depending on the medium they move through (solid or liquid).
Exploration: When a wave enters a material, its velocity changes depending on the properties of the material (e.g., density.)
Detection: By measuring how long it takes for waves to travel through a material, we can detect hidden structures.
Absorption of Waves:
Energy Loss: Absorption refers to how much of the wave’s energy is converted into heat or other forms as it travels through a material. Dense materials tend to absorb waves more strongly than lighter ones.
Exploration: The way a wave is absorbed by different layers of a medium (such as water, rock, or human tissue) can reveal characteristics of those layers.
Detection: In medical ultrasound, the varying absorption levels of sound waves by different tissues give information about the tissue density and presence of abnormalities, like tumors.
Reflection of Waves:
Bouncing Back: Reflection occurs when a wave hits a boundary between two different materials or structures. The wave bounces back, and the angle of reflection depends on the angle of incidence.
Exploration: Reflection is key to exploring hidden structures. For instance, sound waves are emitted from a boat, reflected from ocean floor surface, then detected by boat. This provides the boat with information about depth of water.
Detection: In ultrasound imaging, the way sound waves reflect off tissues (such as organs or blood vessels) is used to generate images of internal structures.
Practice Question
1.What changes do we look for in the properties of waves when using waves to investigate the structure of a material?
2. A wave passes through a material, but takes longer to reach the other side of the material than expected. Suggest what this might indicate about the material.
3. A signal generator is used to generate sound waves. Two sound waves are generated with equal amplitude. Each wave passes through a different material. Explain why the transmitted sound waves have different amplitudes.
4. Bats use sound waves to detect their surroundings such as solid structures, so they can avoid them. Suggest how this works.
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Accordion Content
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