In 1897, J.J. Thomson carried out an important experiment with cathode rays. This experiment helped us learn a lot about what atoms are made of. Here are some major discoveries from his work:

1. Finding Electrons:

   • Thomson discovered that cathode rays are made up of tiny particles that have a negative charge. He called these particles electrons.
   • He also figured out how much charge these electrons have compared to their mass, which he found to be about 1.76 × 10^8 C/kg.

2. Plum Pudding Model:

   • This discovery led him to suggest a new idea about atoms called the plum pudding model. In this model, electrons float in a positive "soup."
   • This was different from the old idea that atoms were indivisible, meaning they couldn't be broken down into smaller parts.

3. Helping Atomic Theory:

   • Thomson's experiment changed how scientists thought about atoms. It helped show that atoms are made of even smaller parts, known as subatomic particles.

Overall, his findings were a big step in understanding atomic structure!