analogy

Name of Topic and Concept: Modern Physics / Atomic Structure

Objective: 3.2: Explain the first atom model which shows that the atom consists of nucleus and electrons.

Grade Level: 11^th grade

‘In the atomic model developed by Rutherford, the positive charge in the atom forms most of the mass and has a centre named the nucleus. Electrons in the spaces outside the core revolve around the nucleus like the planets in the solar system.’

Description of Source: Description of Planets in the Solar System:

The solar system consists of the sun and its planetary system of eight planets, their moons and other non-stellar objects. The vast majority of the system’s mass is in the sun, with most of the remaining mass contained in the planets. The four smaller inner planets called terrestrial planets, the four outer planets are substantially more massive than the terrestrials. All planets have almost circular orbits that lie within a nearly flat disc called the ecliptic plane.

Description of Target: Description of Rutherford’s Atom Model:

Rutherford stated that most of the mass in an atom is concentrated in a nucleus. Thus he developed the planetary model of the atom which put all the protons in the nucleus and the electrons orbited around the nucleus like planets around the sun.

Pictorial Comparison:

 Similarities:

• The positive charge of the atom forms most of the mass and has a centre named nucleus. Similarly, sun in the solar system forms most of the mass and it is at the centre.
• All electrons orbited around the nucleus. Similarly all planets have almost circular orbits that lie within a nearly flat disk.

Dissimilarities:

• All electrons have the same mass but all planets not have the same mass.
• From one orbital to another there might be electron transfer when necessary conditions are provided but in the solar system this is impossible.

References:

• Kurnaz, M.A., Değirmenci, A., Kalyoncu, C., Pektaş, E., Bayraktar, G.,

Aydın, U., & Moradoğlu, Y. (2010). Ortaöğretim Fizik 11 Ders Kitabı. MEB Yayınları, Ankara.

• [ONLINE DOCUMENT] Retrieved from www.ied.edu.hk/apfslt/v13_issue1/yener/page5.htm