What is an Atom and How Do We Know It Exists?

Introduction

• Atoms are the fundamental building blocks of chemistry.
• Scientists have discovered 118 types of atoms, known as elements, arranged on the periodic table.
• Atoms are extremely small and invisible to the naked eye.

Historical Background

Ancient Greece

• Democritus
  • Proposed the idea of atoms (atomos = uncuttable).
  • Believed matter could only be divided until reaching indestructible particles.
  • Lacked evidence; idea was largely dismissed.

Arabic World

• Jabir ibn Hayyan
  • Advanced extraction science through filtration, boiling, and other processes.

1700s Discoveries

• Antoine and Marianne Lavoisier
  • Studied element reactions.
  • Identified elements as substances that cannot be further divided.

Development of Atomic Theory

John Dalton (Early 1800s)

• Proposed atoms based on consistent mass ratios in chemical reactions.
• Suggested atoms of each element are identical in size.

Confirmation of Atoms

• Albert Einstein (1905)
  • Proposed an experiment using equations to confirm atom size and existence.
• Jean Perrin
  • Conducted experiments to confirm atoms' existence.

Visual Confirmation

Scanning Tunneling Microscope (STM)

• Developed in the 1970s by Gerd Binnig and Heinrich Rohrer.
• Electron tunneling technique to "feel" atom surfaces.

Modern Imaging

• Dr. Ara Apkarian's Team
  • Used light with STM to visually confirm nitrogen atoms.
  • Significant advancement in atomic imaging.

Conclusion

• Atoms are proven to exist through experimentation, mathematical calculations, and advanced imaging.
• Despite the meaning "uncuttable," atoms are composed of smaller particles (to be explored in future content).

Additional Information

• Stated Clearly's Series
  • Animation is the first of a four-part series on chemistry fundamentals.

Support and Resources

• Sponsored by the Castle Research Center at UC Irvine.
  • Produced educational content and a video game Bond Breaker.
• Supported by patrons on Patreon.