Investigating The South Crow River: Discharge, Turbidity, Erosion, and Sediments part of MnSTEP Teaching Activity Collection:MnSTEP Activity Mini-collection
In this field investigation, small groups of students will observe and measure characteristics of the South Crow River near Mayer, Minnesota. Data collection on these characteristics will include but not be limited to: speed of current at various places in the river, the amount of sediment (carrying capacity) of the water on this particular day, depth of water at various points across river (for depth profiles), erosion patterns, and river contours. Student groups will record observations and data in journals to aid in their group presentations at the close of this activity. Because this is a guided inquiry activity, the students will not be told exactly how to perform all data collection, but a supply of materials provided by school and individuals will be available for their use. One class period will be used prior to the field activity to share needed information and several class periods will be used following the field activity for the students to prepare their presentations.
Investigating Sound: Using Open Tubes To Demonstrate Beat Notes part of MnSTEP Teaching Activity Collection:MnSTEP Activity Mini-collection
In this interactive demonstration, students will observe while the teacher creates two sound frequencies using open tube resonators of nearly identical length. The nearness in length produces two slightly different frequencies which interfere with each other to produce a beat note Beat notes are used by musicians to tune instruments. Frequencies that differ by less than 7 Hz can be detected by the human ear. The frequency of the beat note is equal to the difference between the frequencies of the two sound waves.