Riding the Waves: An Introduction to Wave Phenomena

Waves and Their Applications

6-PS4-2: Develop and use a model to describe that waves are reflected, absorbed, or transmitted through various materials.

Objective: TSWBAT describe different types of waves and give examples of mediums that cause waves to be reflected, absorbed, or transmitted.

Essential Knowledge

• A wave is a repeating disturbance or vibration that transfers or moves energy (not matter) from place to place through a medium (solid, liquid or gas) or empty space.

• A medium is a material through which waves can travel. It can be a solid, liquid, or gas.

• Mechanical waves require a medium

• Waves are created when a source of energy (force) causes a vibration.

• A vibration is a repeated back-and-forth or up-and-down motion.

• Waves carry energy through empty space or through a medium without transporting matter.

Essential Knowledge

• While all waves can transmit energy through a medium, certain waves can also transmit energy through empty space.

• When there is no medium, certain waves (electromagnetic) can travel through empty space.

Essential Knowledge

• Show video

Multiple Choice

• A ______ is a material through which waves can travel. It can be a solid, liquid, or gas.

• Wave

• Vibration

• Medium

• Speed

Multiple Choice

A _____ is a repeating disturbance or vibration that transfers or moves energy from place to place through a medium (solid, liquid or gas) or empty space.

• Wave

• Vibration

• Frequency

• Speed

Multiple Choice

Which term refers to the rate at which a wave travels through a medium?

• Amplitude

• Wavelength

• Frequency

• Speed

Characteristics of Mechanical Waves

         

•    Mechanical waves require the particles of the medium to vibrate in order for energy to be transferred.

•   For example, water waves, earthquake/seismic waves, sound waves, and the waves that travel down a rope or spring are also mechanical waves. 

• There are two types of Mechanical waves - transverse and longitudinal.

Characteristics of Mechanical Waves - Transverse Waves

         

•    Mechanical waves in which the particles of matter in the medium vibrate by moving back and forth and perpendicular (at right angles) to the direction the wave travels are called transverse waves.

•   Examples of mechanical transverse waves might include some waves in a slinky spring, waves on a rope, strings in a musical instrument, and some seismic waves.

Characteristics of Mechanical Waves - Longitudinal Waves

         

• Mechanical waves in which the particles of matter in the medium vibrate by pushing together and moving apart parallel to the direction in which the wave travels are called compressional or longitudinal waves. The place on the wave that is pushed together is called the compression and the place that is moving apart is the rarefaction.

•    Examples of mechanical compressional/longitudinal waves might include sound waves and some seismic waves.

Characteristics of Electromagnetic (Light) Waves

         

• Electromagnetic waves are waves that can travel through matter or empty space where matter is not present.

•  Some examples are radio waves, microwaves, infrared rays, visible light, ultraviolet rays and x-rays that all travel in electromagnetic waves.

• All frequencies of electromagnetic waves travel at the same speed in empty space. 

Multiple Choice

• Waves that can travel through matter or empty space where matter is not present are....

• Vacuum

• Waves

• Electromagnetic Waves

• Mechanical Waves

Characteristics of Electromagnetic (Light) Waves

         

The behaviors of waves: Refraction

o   Refraction is the bending of waves caused by a change in their speed as they pass from one medium to another. As waves pass at an angle from one medium to another, they may speed up or slow down. The greater the change in speed of the waves, the more the waves will bend.

Multiple Choice

What is wave refraction?

• The bending of waves as they pass from one medium to another

• The formation of headlands and bays

• The change in wave speed

• The change in direction of waves

Wave Reflection

o  Reflection is the bouncing back of a wave when it meets a surface or boundary that does not absorb the entire wave’s energy. All types of waves can be reflected.

Reflections of sound waves, for example, are called echoes and help bats and dolphins learn about their environments.

Multiple Choice

What is the role of reflection in wave phenomena?

• To absorb the wave energy

• To change the direction of the wave

• To increase the frequency of the wave

• To cause interference in the wave

Wave Transmission

• Transmission of waves occurs when waves pass through a given point or medium.

• Sound waves are transmitted through solids, liquids, and gases.

Wave Transmission

• Light waves are transmitted through transparent materials (may be clear or colored materials such as clear or colored filters) that allow most of the light that strikes them to pass through them.

• Opaque materials allow no light waves to be transmitted through them.

• Translucent materials transmit some light, but cause it to be scattered so no clear image is seen.

Multiple Choice

What are some applications of waves?

• Transportation

• Cooking

• Communication

• Cleaning