Biology
Mutualism: How Species Win Together, and When They Cheat
October 13, 2026
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Biology
Mutualism: How Species Win Together, and When They Cheat
October 13, 2026
Botany
Evergreen Trees: 14 Types, Sizes and Zones to Pick From
October 13, 2026
Geology
Examples of Silicate Minerals, Sorted by Structure
October 13, 2026
Chemistry
12 Myths About Chemistry (and What’s Actually True)
October 13, 2026
Before you buy
Books and gear for science readers, students and classrooms, with the specs, prices and editions checked for every pick.
Free to print
Periodic tables, conversion charts and worksheets as free PDFs in US Letter and A4, with answer keys for the quizzes.
Printable Periodic Table
Free periodic table PDFs in color, black and white, blank with a key, kids and an element list, plus a build-your-own customizer.
Periodic Table with Charges
Common ion charges on every element, in color and black and white, with a blank quiz and answer key.
Metric Conversion Chart & Worksheets
Chart, staircase poster, worksheets and quizzes for 3 levels, with answer keys. US Letter and A4 international versions.
Fresh from the lab
Data Science
12 Jobs a Data Scientist Can Do (and What They Pay)
“Data scientist” is one job title sitting on top of a dozen different skill stacks. If you can…
October 13, 2026
Chemistry
Future Trends in Chemical Engineering: 8 Shifts to Watch
Chemical engineering is being pulled in two directions at once. Decarbonization pressure wants plants that run on electricity,…
October 13, 2026
Physics
Levers: The 3 Classes, Formula and Everyday Examples
A lever is a rigid bar that pivots around a fixed point so that a small push at…
October 13, 2026
Science
15 Famous Scientists Born in Tanzania
A teenager in a Tanzanian cooking class notices that hot ice cream mix freezes faster than cold mix.…
October 13, 2026
Chemistry
Astatine Compounds: What Exists and What Is Only Predicted
Contents Nobody has ever held a visible sample of an astatine compound. The longest-lived isotope, astatine-210, has a…
October 12, 2026
Chemistry
Examples of Metallic Compounds, Sorted by Type and Use
A metallic compound is a substance in which one or more metal atoms are chemically bonded to nonmetals,…
October 12, 2026
Chemistry
Bases in Chemistry: Examples, Properties, and pH Explained
TLDR A base is a substance that neutralizes acids. In water, it raises the pH above 7 by…
October 12, 2026
Geography
Natural Resources of Malaysia: What It Has and Where
TLDR The natural resources of Malaysia are led by petroleum and natural gas (mostly offshore, near Terengganu, Sabah…
October 12, 2026
Chemistry
Examples of Acids: 15 Common Ones and Where You Find Them
An acid is a substance that releases hydrogen ions (H⁺) in water. That’s the textbook line, and it…
October 12, 2026
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33Science is an independent publication exploring the natural world — from the chemistry of a single crystal to the life cycle of a star. Clear, curious and rigorously sourced, for readers of every background.
