This model is designed for the study of standing waves in a string with fixed ends. Change the linear mass of the string μ, the tensile force T and the exciting frequency f, and observe the ensuing results. At certain values of the exciting frequency, different types (normal modes) of standing waves settle in the string. It is possible to observe the excitement of the base frequency f_{1}, and the modes of higher order at the frequencies f_{n}=nf_{1}. The condition of excitement of the mode of N-th order is expressed by f_{n} = nv/2l, where v is the speed of propagation of transverse waves in the string, and l is the length of the string.