At ultracold temperatures, neutral atoms can form a Bose-Einstein condensate (BEC) - a kind of atomic laser. Such condensates can be manipulated with high accuracy and are used as the core of high-precision sensors and for the investigation of fundamental physical effects. In a dipole trap generated by a red detuned laser, atoms with any spin orientation can be trapped. Thus, the condensates gain a further degree of freedom and are referred to as spinor condensates. In this project, spin-changing collisions in such a spinor condensate are used to generate entanglement between the atoms. Among others, Einstein-Podolsky-Rosen entanglement with continuous variables was measured and new interferometry concepts were demonstrated, which make the generated entanglement usable to operate atomic sensors with precision beyond the classical boundary.