The Size of Things Viruses are so small that scientists use electron microscopes to see them. 1. Study the number line to help you understand the size differences between viruses, cells, and larger organisms. 2. Then choose common objects to represent two organisms, and write two size-comparison analogies. 1 nanometer 1micron 1 milimeter 1 centimeter 1meter 1 kilometer (10-9m) (10-8m) (10-7m) (10-6m) (10-5m) (10-4m) (10-3m) (10-2m) (10-1m) (100m) (101m) (102m) (103m) Simple Viruses Typical Typical Some Typical Humans Blue Tallest carbon- bacteria animal unicellular mice whales trees containing & organisms, molecules plant such as cells dinoflagellates Analogy: 1.0 Item #1 from Approximate Common object Item #2 from Approximate Size difference Common object number line size representing number line size between items representing item #1 1 and 2 item # 2 Paper clip Room height -7 10-5 2 1. Virus 10 (about 3 cm) Cell 10 or 100 (about 300 cm) 2. 3. Write your analogy in sentence form. A virus is to a paper clip as a cell is to the height of a room. 1. 2. 3. ©2006 WGBH Educational Foundation. NOVA and NOVA scienceNOW are trademarks of the WGBH Educational Foundation. NOVA and NOVA scienceNOW are produced by the WGBH Boston Science Unit. Major funding for NOVA is provided by Google and BP. Additional funding is provided by the Corporation for Public Broadcasting and public television viewers. Major funding for NOVA scienceNOW is provided by the National Science Foundation and the Howard Hughes Medical Institute with additional funding provided by Alfred P. Sloan Foundation and The Kavli Foundation. NOVA scienceNOW is closed captioned and described for viewers who are hearing or visually impaired by the Media Access Group at WGBH. This material is based upon work supported by the National Science Foundation under Grant No. 0229297. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation..