Grade 7 Science

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Grade 7 Science
Sound and Light
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Characteristics of Waves

• What is a Characteristic?

A Characteristic describes something. It is an
adjective or trait.
Ex My hair is blonde.
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Section 1What Are Waves?

• Ex
• Light
• Water
• Sound

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Waves and Energy

• Wave

A disturbance that transfers energy from place to
place.
Energy
defined as the ability to do work.
Medium
The material through which a wave travels.
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Waves and Energy

• Mechanical Waves

Wave that require a medium to travel through.
Student Example Students Book
Ex Gases, liquids, and solids
Notice, the students do not move. The students
are particles in the medium and pass energy to
each other without moving with the wave.
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Waves and Energy

• Vibration

A repeated back-and-forth or up-and-down motion
Ex arms when passing the book.
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Types of Waves

• Transverse Waves

Waves that move the medium at right angles to the
direction the waves travel. Transverse Across
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Types of Waves Cont.

• 2. Longitudinal Waves

Longitudinal waves move the medium parallel to
the direction in which the waves travel.
Longitudinal Lengthwise Sound is a
longitudinal wave.
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