Fourier: Making Waves - Waves | Sines | Cosines - PhET Interactive Simulations

# Fourier: Making Waves

Browser-Compatible Version

• Waves
• Sines
• Cosines

### Sample Learning Goals

• Explain qualitatively how sines and cosines add up to produce arbitrary periodic functions.
• Recognize that each Fourier component corresponds to a sinusoidal wave with a different wavelength or period.
• Mentally map simple functions between Fourier space and real space.
• Describe sounds in terms of sinusoidal waves.
• Describe the difference between waves in space and waves in time.
• Recognize that wavelength and period do not correspond to specific points on the graph but indicate the length/time between two consecutive troughs, peaks, or any other corresponding points.
• Become comfortable with various mathematical notations for writing Fourier transforms, and relate the mathematics to an intuitive picture of wave forms.
• Determine which aspect of a graph of a wave is described by each of the symbols lambda, T, k, omega, and n.
• Recognize that lambda &amp; T and k &amp; omega are analogous, but not the same.
• Translate an equation from summation notation to extended notation.
• Recognize that the width of a wave packet in position space is inversely related to the width of a wave packet in Fourier space.
• Explain how the Heisenberg Uncertainty principle results from the properties of waves.
• Recognize that the spacing between Fourier components is inversely related to the spacing between wave packets, and that a continuous distribution of fourier components leads to a single wave packet.

### System Requirements

Java via CheerpJ simulations run in a browser on most devices.
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