Video Lecture Notes: Converting Units of Length

Overview

• Understanding different units of length.
• Conversion between units.
• Examples of size comparison in nature.

Units of Length

• Nanometers (nm): Smallest unit discussed in the video.
• Micrometers (µm): Larger than nm.
• Millimeters (mm): Larger than µm.
• Centimeters (cm): Between mm and meters.
• Meters (m): Larger than cm.
• Kilometers (km): Largest unit discussed.

Conversion Process

• Scale Factor: Each unit is 1000 times bigger/smaller than its neighbor.
• Conversion Rule:
  • Larger Unit: Divide by 1000 for each step up the scale.
  • Smaller Unit: Multiply by 1000 for each step down the scale.

Example: Converting 6mm

• To Meters: 6mm ÷ 1000 = 0.006m (6 x 10^-3 m)
• To Kilometers: 0.006m ÷ 1000 = 0.000006km (6 x 10^-6 km)
• To Micrometers: 6mm x 1000 = 6000µm (6 x 10^3 µm)
• To Nanometers: 6000µm x 1000 = 6,000,000nm (6 x 10^6 nm)

Example: Converting 340nm to mm

1. 340nm ÷ 1000 = 0.34µm
2. 0.34µm ÷ 1000 = 0.00034mm (3.4 x 10^-4 mm)

Size of Common Objects

• Atoms: 0.1 to 0.5nm
• Molecules (e.g., Glucose): ~1nm
• Viruses: ~100nm
• Bacteria (small cells): ~1µm
• Animal/Plant Cells: 10-100µm
• Human Hair: ~100µm

Visibility with Instruments

• Naked Eye: Down to ~100µm (width of human hair)
• Light Microscope: Down to ~500nm
• Electron Microscope: Down to ~0.1nm

Focusing on Centimeters

• Conversion Relationships:
  • 1cm = 10mm
  • 100cm = 1m
• Conversion Strategy:
  • To meters: Divide by 100
  • To millimeters: Multiply by 10

Example: Converting 30cm to Nanometers

1. 30cm x 10 = 300mm
2. 300mm x 1000 = 300,000µm
3. 300,000µm x 1000 = 300,000,000nm (3 x 10^8 nm)

Additional Information

• Practice questions available through platform link provided in the video description.