NAME ___________________________________________ DATE _____________ PERIOD _______ TEST DATE _____________________________
2011-2012
CORE CONCEPTS & CONNECTIONS – 8th GRADE ADVANCED PHYSICAL SCIENCE
12.2
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Describe the electromagnetic spectrum in terms of frequencies (9 EQT Questions)
Relating wavelength, frequency, and amplitude to energy
Describing the general characteristics and nature of the electromagnetic spectrum
Identifying different ranges of the electromagnetic spectrum for specific purposes based on wavelength
Connection to the PAST
Connection to NOW
Implications on FUTURE
Newton believed that light was made
up of particles. Huygens, argued that
light is a wave. This was a matter of
great debate until Einstein proposed the
photon theory. Einstein integrated both
theories.
We use radio waves for
communication, microwaves for
cooking, infrared to see images in the
dark, x-rays in medicine, and gamma
rays to destroy cancer cells
Dentists will use digital x-rays that
have higher resolution and can be
stored on a computer. The harmful
exposure to the digital x-ray is 1/10th
that of dosage today.
Vocabulary
Core concept
The electromagnetic spectrum can be expressed in terms of energy, wavelength, or frequency.
Each part of the electromagnetic spectrum is related to the others in a precise mathematical way.
wavelength,
frequency,
electromagnetic spectrum
Core concept
The distance between adjacent crests in a series of periodic waves is called a wavelength. A
property of a wave that describes how many wave patterns or cycles pass by in a period of time is
called the frequency. Frequency is often measured in Hertz (Hz), where a wave with a frequency
of 1 Hz will pass by at 1 cycle per second. Gizmo – Hearing Frequency & Volume Gizmo –
Doppler Shift
Vocabulary
Hertz,
crest,
trough
Core Concept
The wavelength of a wave is equal to the speed divided by it frequency. The wave speed for
any electromagnetic wave is equal to c (the speed of light) in a vacuum. The wavelength
increases as the frequency decreases. Thus, an electromagnetic wave with a long wavelength
has a low frequency and an electromagnetic wave with a short wavelength has a high frequency.
The amplitude and speed do not change as the frequency or wavelength changes.
Vocabulary
c = speed of light,
amplitude