1. Radiocarbon dating Teaching notes

2. Where does the resource fit? The resource is aimed as an activity to assist on the consolidation of the learning of radiocarbon dating and half life. OCR Gateway Additional Science B – Radiation for life. OCR 21 st Century Additional Science A – Physics – Radioactive materials. AQA Additional Science – Physics – Atoms and radiation. Edexcel Additional Science – Physics – Advantage and disadvantages of using radioactive materials.

3. How to use the resource The resource is in the form of a pdf file and can be opened up with software such as adobe acrobat reader. There are 2 pages to the resource. Page 1 (sheet 1): radioactive dating using carbon-14. There is a table of data for activity against time. The students are expected to draw a graph and answer the questions provided. Page 2 (sheet 2): radioactive dating using usranium- 238. There is a table of data for % of U-238 left against time. The students are expected to draw a graph and answer the questions provided.

4. Answers Radioactive dating using carbon-14 1.(sensible graph) 2.5,700 years 3.a) 13,500 years old b) 750 years old c) 31,750 years old 4.a) 1600 cps b) 28 cps c) 0 cps d) 2900 cps 5.Not precise enough for CSI. Activity will have hardly decreased. 6.After 70,000 year carbon-14 has fully decayed, so anything older cannot be determined. 7.a) 11,400 years old b) 28,500 years old 8.a) 380 cps b) 200 cps

5. Answers Radioactive dating using uranium-238 1.(sensible graph) 2.4.5 billion years 3.a) 5.9 billion years old b) 0.25 billion years old c) 2.5 billion years old 4.a) 70 % b) 10 % 5.a) 25 % b) 3.5 % 6.a) 3 half-life’s b) 4 half-life’s 7.a) The atomic mass reduces by 4 to account for the alpha particle emitted (2 protons and 2 neutrons) b) U-234 > Th-230, Th230 > Ra-226, Ra-226 > Po-218, Po-218 > Pb- 214, Po-214 > Pb-210, Pb-210 > Pb-206 8.Th-234 > Pa-234, pb-214 > Bi-214, Bi-214 > Po- 214, Pb-210 > Bi-210, Bi- 210 > Po-210