Chemistry Lecture Show Notes

Introduction

• Importance of Observation: Essential in chemistry and science.
• Test of Observational Skills: Example with TV cameras.

Purpose of Filming

• Oxford University is filming the lecture for iTunes.
• Audience participation with cheering "Hello from Oxford".

Nature of the Show

• Not a magic show; scientific explanations will be provided.
• Safety Reminder: Don't try these experiments at home. Some chemicals and equipment are dangerous.

First Demonstration

• Mixing colorless liquid with blue liquid → green color.
• The demo was set aside for later observation.

Clock Reaction Demonstration

• Three volunteers added chemicals (A, B, C) to a hot plate stirrer.
• Observation: Solution changed to blue, purple, and back again.
• Explanation: A "clock reaction" with 13 reactions creating cyclical color changes.

Dichromic Chemical Demonstration

• Chemical appears red and green simultaneously.
• Explanation: It absorbs blue and green light, but because our eyes are more sensitive to green, it appears both colors:
  • More green when less light passes through.
  • More red when more light passes through.

Arithmetic in Solution

• Initial mix of colorless and blue solution → green → red over time.
• Demonstration: Divided solution into two different colors.
• Explanation: Indicator sensitive to oxygen levels; reactions between glucose and sodium hydroxide change the color.

Cold Light/Chemiluminescence Demonstration

• Volunteers mixed chemicals → solutions emitted light without heat.
• Real-Life Application: Glow sticks.

J-Cloth and 10 Pound Note Burning Demonstration

• Cloth soaked in a mixture of water and a flammable liquid burned without being consumed.
• Explanation: Water keeps the cloth/note cool while flammable material burns.

Hydrogen Peroxide and Catalase Demonstration

• Mixing hydrogen peroxide with an enzyme simulated foaming action through oxygen release.

Cold Demonstrations (Dry Ice and Liquid Nitrogen)

• Dry Ice (-78°C): Sublimates into CO2 gas creating a fog by freezing water vapor.
• Liquid Nitrogen (-196°C):
  • Rubber tubing became brittle and solid.
  • Flowers became brittle and shattered upon freezing.
  • Balloon shrunk in liquid nitrogen, expanded when warmed.
  • Banana frozen solid, demonstrating lower temperatures on organic material.

Fiber Optics and Light Bending Demonstration

• Laser beam bent around a tubing spiral inside the tube but trapped in the wall.
• Real-Life Application: Fiber optics for data transmission.

Mains Light and Frequency Demonstration

• Light plugged into AC current swung around; appeared to blink due to AC current phase changes.
• Application: Estimating frequency with a digital camera.

Endothermic Reaction Demonstration

• Metal container on wood mixed with a chemical froze to the block.
• Could lift the block showing the strength of the bond created.

Hydrogen and Helium Balloons Demonstration

• Helium balloon slightly popped without significant reaction.
• Hydrogen balloon → Rapid burn/ minor explosion showing hydrogen’s flammability.
• Safety Tip: Cover ears and open mouth to mitigate potential shockwave effects during explosions.

Final Demonstration (H2+O2 Balloon)

• Mixture of hydrogen and oxygen in a balloon burned rapidly producing a significant bang.
• Safety Protocol: Hands over ears and mouths open to avoid ear damage from the shockwave.

Conclusion

• Recap of experiments and explanations.
• Emphasize learning and curiosity in science.