Advantages of Electron Microscopes and Calculations of Magnification

Introduction

• Overview of the topic: Differences between light microscopes and electron microscopes.
• Objective: By the end of the lesson, understand the advantages of electron microscopes and learn how to calculate magnification.

Light Microscopes

• History: Invented hundreds of years ago.
• Use: Have been used extensively to study cells.
• Examples: Structures like the nucleus discovered using light microscopes.
• Advantages: Allows magnification (bigger image than the object).
• Limitations:
  • Limited Magnification: Cannot easily view structures inside the nucleus.
  • Limited Resolution: Images are blurred and lack fine detail.

Electron Microscopes

• Development: Invented to explore detailed cell structures.
• Key Advantages:
  • Greater magnification than light microscopes.
  • Higher resolution allows for detailed visualization of cell structures.
• Example: Nucleus image with detailed visibility using electron microscope.

Calculating Magnification

• Equation: Magnification = Size of Image / Size of Real Object.
  • Important: The equation is provided in exams but not the calculation triangle.
• Example Calculation:
  • Question: Measure image size of nucleus and calculate magnification.
  • Given: Image size = 45 mm, Real size = 0.01 mm.
  • Solution: Magnification = 45 mm / 0.01 mm = 4,500 times.

Practice Problems

• Problem: Measure length of mitochondrion.
  • Given: Image size = 30 mm, Real size = 0.03 mm.
  • Solution: Magnification = 30 mm / 0.03 mm = 10,000 times.
• Problem: Calculate real size of cell given magnification.
  • Given: Image size = 87 mm, Magnification = 2,000 times.
  • Solution: Real Size = 87 mm / 2,000 = 0.435 mm.

Conclusion

• Recap of the advantages of electron microscopes over light microscopes.
• Practice of magnification calculations with provided problems.
• Additional resources available in the vision workbook.

• Notes: Remember to review calculations and concepts regularly to solidify understanding.