What reading level is the Library of Subatomic Particles series?

The Library of Subatomic Particles series by Fred Bortz is at a Grades 9.5–10 reading level (average Grade 9.8). Intended for Upper Grades (Ages 12+). There are 6 books in the series.

What order should I read the Library of Subatomic Particles books?

The Library of Subatomic Particles series has 6 books in order: 1. The Electron (The Library of Subatomic Particles), 2. The neutrino, 3. The neutron, 4. The Photon (The Library of Subatomic Particles), 5. The proton, and 1 more.

What age is the Library of Subatomic Particles series appropriate for?

The Library of Subatomic Particles series is recommended for Upper Grades (Ages 12+). The average content intensity is 1/5.

Library of Subatomic Particles Books in Order

6 books by Fred Bortz. Reading level: Grades 9.5–10. Upper Grades (Ages 12+).

Series books grow with readers — but that's also the trap. Most series start at one reading level and one content intensity and drift upward over the course of the run. Library of Subatomic Particles (6 books by Fred Bortz) lands at reading level Grades 9.5–10, with average content intensity 1/5. Intensity stays consistent across the series — a kid who can handle the first book can generally handle the rest.

The reading-order table below lists every book with per-volume reading level and intensity badges so you can spot any escalation before it catches your reader off guard. For a deeper dive into how we score text difficulty vs. emotional weight separately — and why series readers especially benefit from that split — see our methodology page.

Books

Grades 9.5–10

Reading Level

1/5

Avg. Intensity

Upper Grades

Content Intensity Across the Series

Consistent

Content stays at a steady intensity level throughout the series.

First book Latest book

Library of Subatomic Particles Reading Order

#	Title	Reading Level	Content
1	The Electron (The Library of Subatomic Particles) Fred Bortz	Level 9-10	Gentle
2	The neutrino Alfred B. Bortz	Level 9-10	Gentle
3	The neutron Alfred B. Bortz	Level 9-10	Gentle
4	The Photon (The Library of Subatomic Particles) Fred Bortz	Level 9-10	Gentle
5	The proton Alfred B. Bortz	Level 10	Gentle
6	The Quark (The Library of Subatomic Particles) Fred Bortz	Level 9-10	Gentle

Level 9-10 Gentle

Questions about the Library of Subatomic Particles series

What reading level is the Library of Subatomic Particles series?: The Library of Subatomic Particles series by Fred Bortz is at a Grades 9.5–10 reading level (average Grade 9.8). Intended for Upper Grades (Ages 12+). There are 6 books in the series.
What order should I read the Library of Subatomic Particles books?: The reading-order table above lists all 6 books with per-volume reading level and intensity ratings. Start with book 1 and read in publication order unless the table indicates a different recommended order for newer readers.
What age is the Library of Subatomic Particles series appropriate for?: The Library of Subatomic Particles series is recommended for Upper Grades (Ages 12+). The average content intensity is 1/5. Check the intensity trajectory above to see whether content gets heavier across the series — if it does, sensitive readers may want to stop earlier in the run.