For exploring the concept of resonance through sympathetic and forced vibrations, and phenomenon of beats. Comprises two matched nickel plated tuning forks of frequency A(426.6), each mounted on top of hollow wooden box open at one end. One fork is provided with a sliding mass on one prong by means of which its frequency can be varied from the nominal 426.6Hz. When both forks are sounded a clearly audible ‘beat’ is produced, its rate depending upon the difference in frequency between the forks.