Units of Length and Conversion

Overview

• Discusses different units of length and how to convert between them.
• Covers examples from atoms to larger scales.

Units of Length

• Nanometers (nm)
• Micrometers (µm)
• Millimeters (mm)
• Meters (m)
• Kilometers (km)
• Centimeters (cm)

Scale

• Each unit is 1000 times bigger or smaller than the next.
  • 1 km = 1000 m
  • 1 nm = 0.001 µm

Conversion Method

• Converting to a Larger Unit: Divide by 1000 for each step.
  • Example: 6 mm to meters: 6 ÷ 1000 = 0.006 m (6 × 10⁻³ m)
  • Convert to kilometers: 0.006 ÷ 1000 = 0.000006 km (6 × 10⁻⁶ km)
• Converting to a Smaller Unit: Multiply by 1000 for each step.
  • Example: 6 mm to micrometers: 6 × 1000 = 6000 µm (6 × 10³ µm)
  • Convert to nanometers: 6000 µm × 1000 = 6,000,000 nm (6 × 10⁶ nm)

Conversion Across Non-Adjacent Units

• Example: 340 nm to mm
  • Convert nm to µm: 340 ÷ 1000 = 0.34 µm
  • Convert µm to mm: 0.34 ÷ 1000 = 0.00034 mm (3.4 × 10⁻⁴ mm)

Sizes of Common Objects

• Atoms: 0.1 to 0.5 nm
• Medium molecules (e.g., glucose): ~1 nm
• Viruses: ~100 nm
• Bacteria: ~1 µm
• Animal/Plant cells: 10-100 µm
• Human hair: ~100 µm

Visibility with Different Microscopes

• Naked Eye: Sees down to ~100 µm
• Light Microscope: Sees down to ~500 nm
• Electron Microscope: Sees down to ~0.1 nm

Centimeters

• 1 cm = 10 mm
• 100 cm = 1 m
• Conversion:
  • cm to m: Divide by 100
  • cm to mm: Multiply by 10

Conversion Example

• Convert 30 cm to nm:
  • 30 cm × 10 = 300 mm
  • 300 mm × 1000 = 300,000 µm
  • 300,000 µm × 1000 = 300,000,000 nm (3 × 10⁸ nm)

Conclusion

• For further practice, access the provided links to the platform for additional resources and exercises relevant to the video content.