1. The Discovery of Radioactivity GROUP 8 Richard Loew JaceGrandinetti Edward Duran Emil Blumburg

2. Topics • Discovery of Radioactivity • Properties of Radioactive atoms • Impact on Physics • Future Applications

3. Phosphorescencevs Radioactivity Becquerel discovered radioactivity while studying phosphorescence. Found that uranyl sulfate, K2UO2(SO4)2, could expose a photographic plate without being exposed to light. Found other uranium compounds did the same, even if they were known to be non-phosphorescent.

4. Properties of Radioactive Compounds • Generally heavy atomic weight (Z < 82) • Emission of several types of radiation • Penetration • Ionization • Deflection by an electric field • For brevity, Becquerel denoted the rays as α, β, and γ

5. The α-ray Minimal penetration Slight deflection from magnetic field Positively charged Charge-to-mass ratio is more than twice that of the canal ray (Proton)

6. The β-ray • Moderate penetrative ability • Negatively charged • Very deflected by an electric field • Charge-to-mass ratio roughly equal to cathode rays (electrons) • Calculated by finding the radius of curvature when passing through an electric field.

7. The γ-ray • Extremely penetrating • Not deflected by electric field • Similar to X-rays, but not as ionizing. • Exposure is hazardous

8. Impact of Discovery More in-depth analysis of the nature of the nucleus Expansion of the periodic table Led to the invention of the atomic bomb Medical Imaging Direct cause of death for both Ernest Rutherford and Marie Curie

9. Future Applications

10. Bibliography • Henri Becquerel - Nobel Lecture: On Radioactivity, a New Property of Matter". Nobelprize.org. Nobel Media AB 2013. Web. 2 Dec 2013. http://www.nobelprize.org/nobel_prizes/physics/laureates/1903/becquerel-lecture.html • Ernest Rutherford. “Radio-activity”. 2nd edition, 1905. 24 Nov 2013 • http://chem-guide.blogspot.com/2010/04/radioactive-rays-alpha-ray-beta-ray.html • DC/Marvel comics and 20th Century Fox

11. Questions?