Forces, space and radioactivity

The motion of an object can be predicted by analysing the forces that act on the object. Balanced forces have no effect, while unbalanced forces can lead to change in acceleration.

In 1687, Isaac Newton created three laws of motion to describe the relationship between a body and the forces acting upon it, and how the body moves in response to those forces.

Work and energy looks at GPE, KE and elastic energy, and how they are conserved. It also looks at the relationship between force and extension, as well as how car features absorb energy in a crash.

Moving objects have momentum, and forces cause it to change. The total momentum in an explosion or collision is conserved and stays the same. Equations of motion apply to uniformly accelerated motion.

The Earth forms part of a family of eight planets which orbit around the Sun. This solar system forms part of a huge collection of stars which form the Universe and are also known as galaxies.

The study of atomic absorption spectra allows us to determine the chemical make-up of stars. It shows that galaxies are moving away from us in an expanding Universe.

Three subatomic particles have different charges and masses. Radioactive particles decay and release alpha, beta and gamma radiation - natural and artificial sources of background radiation.

Radioactive isotopes are used for blood flow monitoring, cancer treatment, paper mills, carbon dating and smoke alarms. Each isotope used in these applications has a characteristic half-life.

Nuclear fission is the splitting of a radioactive nucleus to release energy. High-energy collisions between light nuclei can result in fusion, which releases energy.