Showing posts with label amplitude. Show all posts
Showing posts with label amplitude. Show all posts

Saturday, December 22, 2012

Programming the Sine Function - the frequency parameter

  As shown in the following diagram, the amplitude is the maximum and minimum values for y when graphing the equation y =Asin(a). Change A, and the heights (amplitudes) change. 
   This  project can be viewed at on the Scratch web site.
   I’ve just uploaded to Scratch the next project in the Sine series that looks at the frequency of the sine function and the parameter that controls it. You can view and download the project at
from popswilson’s My Stuff page. Below is a screen shot of the project.
   After the first sine curve (in blue) with an amplitude of 100 is drawn, set the frequency to another value and press the space bar to plot the new curve in the color red. The red curve in the screen shot is the plot of the sine curve with a frequency of two.
   The FM after the call numbers of a radio station refers to frequency modulation. The signal (an electromagnetic wave) that carries the radio broadcast from an AM station is modulated (changed) by varying the amplitude of the wave. Varying the frequency of the wave modulates an FM radio signal. 

Saturday, December 15, 2012

Two Colorful Sine Waves

   In the recent post, The Sine Function, I explained the origin of the sine function as a ratio of sides in a right triangle and then described how to build the sine function script in Scratch.
   In Scratch parlance, making modifications to an existing Scratch project is called a remix. Since uploaded Scratch projects can be downloaded by Scratch users, remixing is encouraged and often leads to new and interesting variations on a theme.
   The remix of my Sine project has been uploaded to My Stuff at
where you can download a copy.
   Here's a short video that describes how the project works.

Monday, December 10, 2012

Riding the Sine Wave

   I just uploaded a new project to my Scratch folder at
called The Sine Wave.
   I would imagine a surfer  likes big waves that arrive frequently. The Sine Wave project explains the sine ratio as derived from a right triangle, the unit circle, and then how to graph the sine function in Scratch.
   The project allows the user to change the amplitude of the sine curve. Oh if it was only that easy for the surfer!
   A free pdf file for this project is available on request by sending an email to
  The next sine function project will allow the user to play with the frequency of the wave.