Leaving Certificate science syllabuses are designed to incorporate the following components: science for the enquiring mind, or pure science, to include the principles, procedures and concepts of the subject as well as its cultural and historical aspects. Science for action, or the applications of science and its interface with technology. Science, which is concerned with issues – political, social and economic – of concern to citizens.

The study of physics includes all the elements outlined above. The main topics covered in the physics course are:

• Optics
• Mechanics, Energy, Power, Force, Pressure etc.
• Heat
• Waves: Light and Sound waves and their properties
• Static and Current Electricity
• "Modern Physics"
• Nuclear Physics including Radioactivity and Nuclear Energy
• Options: Particle Physics or Applied Electricity

Physics is offered at higher level or ordinary level in SMGS. It is a very enjoyable and rewarding subject for students who like to know how and why things work.

The school is actively involved in Science Exhibitions: in 2009 Eric Higgins won the Comreg Award and second prize in his category at the BT Young Scientist and Technology Exhibition. Richard O Shea and Ruairi Kenny also won 3rd prize at the exhibition in the physical, chemical & mathematical sciences category. Richard also won his category in the 2009 Scifest competition in C.I.T in May. In fact all eight projects (14 students) from SMGS that were entered in the Scifest won prizes.