1. By: Alyssa, Isaiah, Liam and Jessica
Atom Detectives
By: Alyssa, Isaiah, Liam and Jessica

2. Question 1) Who is Joseph John Thomson?
Thomson was born in 1856 and died in He was born in a small town near Manchester. His ambition in life was to be an engineer but that was replaced by being awarded a scholarship in chemistry. The scholarship that he received was in memory of John Dalton. When Thomson turned 28, he became a professor at the Cavendish Laboratory, Cambridge University

3. Question 2) What was Thomson's main achievement in life?
1897, Thomson discovered the electron while investigating the conductivity of electricity by gases at very low pressures. After 20 years of collecting data, Thomson was convinced that electrons were negative particles of electricity. An exception was that he still needed more evidence and research to convince the scientific world, so he asked Wilson to try and take a photo of an electron to show the people. He finished building the suitable camera which was sealed in a glass chamber where electrons could be produced In The experiment was a success and the electron was photographed. After the evidence of the electron was found, he was still worried about telling the world his new theory of the atom, because until recently the atom was thought of as a single solid particle.

4. Question 3) What was the main difference between Thomson's model and Dalton's model?
The main difference between the two was that Dalton thought that matter was made of small, hard spheres that were different for different elements and also that the smallest part of an element was called an atom while Thomson thought that atoms were made of smaller particles called sub particles that he proposed the "raisin bun" model of the atom. He also thought that an atom was a positively charged bun with negatively charged particles spread out in it like raisins which means that the atom was neutral with both positive and negative particles.

5. Question 4) What advances in technology made it possible for Thomson to successfully complete his investigations?
Advances in technology that helped Thomson complete his investigations were electronics, cameras and data. All of these advances helped him by showing the details of an electron, forming a hypotheses and finding more research and evidence for an electron to show the scientific world his discovery.

6. Some facts about Thomson's model of atomic structure - 1899
Atoms consisted of rings of negative electrons embedded in a sphere of positive charge (the plum pudding model).
The positive and negative charges balance to make the atom neutral.
The mass of the atom was due to the nucleus.
The mass of an electron was 1/1840 of the mass of hydrogen, the lightest atom.
There were 1840 electrons in an atom of hydrogen.

7. Limitations of Thomson's model:
The positive and negative particles being together would attract one another and become neutral.
It can't explain the chemical properties of different elements.
Thomson's model must contain enough positive charge to balance negative charge of electrons.

8. Thank you for tuning in! :)