Ionizing (or ionising) radiation is radiation composed of particles that individually carry enough kinetic energy to liberate an electron from an atom or molecule, ionizing. Smoke alarms contain a weak source made of Americium-241. Alpha particles are emitted from here, which ionise the air, so that the air conducts electricity and a small current flows.
If smoke enters the alarm, this absorbs the particles, the current reduces, and the alarm sounds. Am-241 has a half-life of 460 years. SMOKE DETECTORS | Ionising radiation can damage living cells and these may be killed or may become cancerous Ionising radiation can initiate a cancer and can cause hereditary defects | In paper mills, the thickness of the paper can be controlled by measuring how much beta radiation passes through the paper to a Geiger counter. THICKNESS CONTROL | | | Ionising radiation is dangerous because when it comes into contact with our skin, electrons are knocked away in the cells which are in vulnerable tissue. This ionises cells in the body. This ionisation damage cells and the damage done depends on the exposure to radiation. Short exposure leads to cell mutation and the development of cancer. Long exposure leads to lots of cells being destroyed and to radiation sickness. | Even after it has been packaged, gamma rays can be used to kill