8.  Explain how the main features of a Scanning Tunnelling Microscope allow an image to be formed  Explain how the main features of a Transmission Electron Microscope allow an image to be formed.  Explain what the resolution of a TEM is limited by.

9.  Transmission Electron Microscope (TEM  1931  Scanning Tunnelling Microscope (STM)  1981

10. Quantum tunnelling Piezoelectricity Resolution

15.  A TRANSDUCER changes energy between different forms  Piezoelectric materials: Voltage  Strain  So apply a voltage  Get a strain  Max strain is ~0.1%

16.  Lead Zirconate Titanate (PZT)

17.  Quartz is a piezoelectric  And it has a natural frequency (as does everything)  So as it vibrates it creates a stable oscillating voltage

18.  What does the diffraction pattern from a single slit look like?

21.  Two stations, one for each type of microscope.  Complete the tasks at each station, following the task list.  Check your learning against the understanding checklist.  Extension: Read one of the articles related to today’s lesson (quantum tunnelling, uses of piezoelectrics, top-of-the-range electron microscopes)

22. An electron gun produces a beam of electrons. A magnetic condenser lens forces the electrons into a collimated beam. The electrons pass through a very thin sample and are scattered. The objective lens deflects the scattered electrons to form an enlarged, inverted ‘first’ image The magnifier lens focuses electrons from the centre of the first image to form a magnified final image on a screen