The early development of an animal results from a highly complex sequence of interactions within and between cells to transform a fertilised egg into a functional embryo. A major challenge in the field of morphogenesis is explaining how coordinated cell shape change, growth and movement create the structures that we are familiar with, and what drives the processes that pattern and control this behaviour. Embryos are complicated mechanical systems for which we have a wealth of morphological data about the shapes and movements of cells but it is diffcult to understand how these movements emerge as a result of force-generating mechanisms within the embryo. A new, force-based modelling technique designed to test hypotheses about dynamic processes within an embryo is presented. The model focusses on how the mechanical properties of a cell and inter-cellular forces affect the movements we see within a tissue. It is designed to probe the relationships between cellular and tissue behaviours; such as how forces propagate through a system or the response of a tissue to applied forces. The novel features of the model are discussed along with analysis of tissue and cellular behaviours for different idealised systems, describing how the parameters of the model affect experimental observables. The model is applied to two real world systems. Firstly examining the role of boundary conditions on the patterning seen in the formation of the zebrafish forebrain neural plate. Secondly, two proposed hypotheses for the formation of the primitive streak in the chick embryo are investigated and compared. These applications demonstrate how the model can be used to complement experimental studies and help to tease out the mechanical processes driving morphogenesis.