Lab Name Linear Models
Subject Area Mathematics
Grade 8
Topic Interpret Linear Models
Experiment Title Measuring the Strength of different Signals changing locations (indoor & outdoor) and using the data gathered by analyzing the results.
Hardware
  • COSMOS Toolkit: Computer Node
  • COSMOS Toolkit: Mobile Node
  • Software Defined Radio (i.e., ADALM Pluto SDR, RTL-SDR)
  • Additional Transmitter (i.e., Walkie-Talkie, baby monitor, car key, or a radio control toy)
Software
  • COSMOS Toolkit: Framework
  • GNU Radio Companion
Number of Sessions to teach the topic 5 - 7 sessions (45 mins)
Educational standards to be addressed
  • S-ID.7
    Interpret the slope (rate of change) and the intercept (constant term) of a linear model in the context of the data.
  • S-ID.8
    Compute (using technology) and interpret the correlation coefficient of a linear fit.
  • S-ID.9
    Distinguish between correlation and causation.
COSMOS concepts to be used for the lab How distance impacts radio signal strength via wireless receivers. The effect attenuators have on signal strength and how reflection impacts wireless signal strength.
K12 Educational Goals (How the educational goals are achieved through teaching using the experiment, how the topic is connected to the COSMOS concepts used) Students will begin to look at data using statistical analysis. This lesson will build on the their prior knowledge of linear and non-linear relationships and they segue into working with scatter plot, standard deviation, and variance of non-linear data. To determine the relationship between signal strength and distance; show and describe the relationship in a table and a graph; to explore statistical data when represented in a scatter plot.
Short Description and Walk-through of the experiment Students will perform the experiment indoors and outdoors. Students will explore signal strength by sending radio waves to the SDR-Receiver at different distances. Students will begin by measuring signal strength starting at 0 meters and then increasing by 5 meter increments, stopping at 50 meters. Instead of taking one signal strength reading in a linear path, the students will record 5-6 signal strength readings in a circular path around the transmitter before moving to the the next distance. Each distance will have 5-6 signal strength recorded base on moving in a circular motion around the receiver.

Students will collect the signal strength data and display the information as raw data (coordinate form). Students will take this data and input it into a table, create a graph, and then develop a linear equation using line of best fit. Students will discuss noticing, pattern, possible trends and discuss how the similarities and differences in signal strength both indoors and outdoors. Explore outliers and what may cause an outlier.
Testbed mapping of the experiment The experiment can be extended by executing it into a testbed (ORBIT/COSMOS) through the following steps:
Using different nodes on the testbed (one as a receiver and one as a transmitter) and then examine how signal strength is impacted when sent to nodes in different locations.

Possibly explore signal strength with different attenuators such as water, cement, wood, plastic, etc.; possibly explore what happens when a receiver is submerged under water at different depths.

Experiment Execution

Select the appropriate function or the node (Transmitter or Receiver) and press START to begin the experiment. In order to terminate the experiment press STOP.
Transmitter Receiver

Experiment Material

NGSS Lesson Plan
Worksheet
Fill Worksheet
Other

© 2018 COSMOS Project. Created by Juditha Capa Damiao, Joseph F. Lamb School
Melissa Sanchez, Urban Assembly Academy for Future Leaders
Deidre Walker, New York Harbor School