1. McNair Middle School Physical Science

2. Bellringer What do you think of when you hear the word wave? Write a brief description of what you think a wave is. Then write a paragraph describing a time when you might have experienced waves.

3. Standards S8P4 – Students will explore the wave nature of sound and electromagnetic radiation A. Identify the characteristics of electromagnetic and mechanical waves D. Describe how the behavior of waves is affected by medium. F. Diagram the parts of the wave and explain how the parts are affected by changes in amplitude and pitch.

4. Essential Question

5. Waves A wave is any disturbance that transmits energy through matter or empty space. Carry energy away from its source Does work on everything in its path Most waves transfer energy by the vibration of particles in a medium. A medium is a substance through which a wave can travel. Can be a solid, liquid, or gas

6. Waves Waves that need a medium to transfer energy are called mechanical waves Ex: Earthquake Some waves can transfer energy without going through a medium Electromagnetic waves do not need a medium to transfer energy. Ex: Energy from the sun

8. Types of Waves Transverse – waves in which particles vibrate in an up and down motion Transverse Transverse means “across” All electromagnetic waves are considered transverse waves because the waves are made of vibrations that are perpendicular to the direction of the motion. Crest is the highest point of a transverse wave Trough is the lowest point of a transverse wave http://my.hrw.com/sh2/sh07_10/student/flash/visual_con cepts/70355.htm

9. Types of Waves Longitudinal waves Longitudinal The particles of the medium vibrate back and forth along the path that the wave moves. Ex: Spring Rarefractions – part of the wave where the particles are spread apart. Compressions – part of the longitudinal wave where the particles are crowded together http://my.hrw.com/sh2/sh07_10/student/flash/visual_con cepts/70356.htm

10. Longitudinal Wave

11. Types of Waves Surface waves – combination of longitudinal and transverse waves Ex: ocean wavesocean waves Sound waves: are a type of longitudinal wave. They travel by compressions and rarefractions of air particles.