Linear Relationships in Geophysics: Soil Moisture Investigation
Students will use linear equations to understand soil moisture and other underground phenomena. Students will learn to write, interpret, and apply linear models from real-world data, connecting mathematical concepts to practical geophysical problems.
Overview
Students start with containers of dry, damp, and wet sand and ask how soil moisture could be measured without digging. After videos on near-surface geophysics and soil moisture, they use the Groundwater Movement Simulation and the Water Scenario Game. They then plot provided data on electrical resistance and sound wave speed against moisture, calculate slope and y-intercept, and write linear equations. Word problems build skill in solving for unknowns and noting model limitations. Groups model a new soil data set, make predictions, and present as geophysics consulting teams to clients such as farmers or city planners, followed by peer feedback and individual reflection. The plan spans five days, with 70-minute sessions on Days 1, 2, and 5.
Lesson Objectives
- Write linear equations from data tables Students will be able to interpret slope and y-intercept in real contexts Students will be able to create and analyze linear graphs Students will be able to use linear equations to make predictions Students will be able to present findings in group projects
Standards
NGSS · 2
- HS-ESS2-5Plan and conduct an investigation of the properties of water and its effects on Earth materials and surface processes.
- HS-ETS1-4Use a computer simulation to model the impact of proposed solutions to a complex real-world problem with numerous criteria and constraints on interactions within and between systems relevant to the problem.
CCSS Math · 4
- HSA-CED.A.2Create equations in two or more variables to represent relationships between quantities; graph equations on coordinate axes with labels and scales.
- HSF-IF.B.4For a function that models a relationship between two quantities, interpret key features of graphs and tables in terms of the quantities, and sketch graphs showing key features given a verbal description of the relationship. Key features include: intercepts; intervals where the function is increasing, decreasing, positive, or negative; relative maximums and minimums; symmetries; end behavior; and periodicity.
- HSF-BF.A.1Write a function that describes a relationship between two quantities.
- HSA-REI.B.3Solve linear equations and inequalities in one variable, including equations with coefficients represented by letters.