Final answer:
Sally should use a balance or scale to find the mass of a dirt sample from a riverbank, ensuring that she subtracts any container weight by using the taring method.
Step-by-step explanation:
To determine the mass of a sample of dirt from a riverbank, Sally should use a balance or scale. These tools are suitable for measuring small to moderate amounts of mass with precision. Specifically, for solid materials like a dirt sample, a digital balance can provide an accurate measurement of mass in grams. Sally would place the sample on the balance and record the weight displayed, ensuring she has the mass of the dirt only and subtracting any mass from the container holding the sample if necessary.
In a lab setting, geologists and chemists often use a tared approach. This means they first weigh the empty container (a process known as taring the balance), and then add the sample to the container and weigh again. The difference in mass gives the precise mass of the sample alone. Tools like sieves can be used for grain size analysis but are not necessary for simply determining mass.