Chemistry
- How soap cleans
A soap molecule holds water at one end and grease at the other. That is how it lifts oil off a plate, and how it breaks some viruses apart.
- 7min read
- 10min listen
- 26questions
- The chemistry of life
Why bread can feed you and a cotton shirt never could, though both are built from the same sugar.
- 9min read
- 11min listen
- 36questions
- Carbon chemistry
How one element makes diamond and pencil lead, fuels, alcohols and plastics, and the molecules of every living thing.
- 8min read
- 10min listen
- 30questions
- Metals and materials
Why gold is found as nuggets and aluminium never is, why a little carbon turns soft iron into steel, and why a block of zinc keeps a ship from rusting.
- 9min read
- 10min listen
- 32questions
- Mixtures and separating
Why no filter paper can take the salt out of sea water, and the handful of methods, from a salt pan to a still, that can.
- 9min read
- 10min listen
- 34questions
- Acids and bases
What makes something an acid or a base, how the pH scale ranks them, and what happens when the two meet.
- 8min read
- 10min listen
- 34questions
- Fire and energy
Where the heat of a fire comes from, why a match has to be struck, and why water saves a campfire but turns a pan of burning oil into a fireball.
- 9min read
- 10min listen
- 31questions
- Chemical reactions
What a chemical reaction does to atoms, where a burnt log’s mass goes, what decides how fast a reaction runs, and how a catalyst speeds one up without being used up.
- 7min read
- 10min listen
- 28questions
- How atoms bond
Why atoms bond, the three ways they do it (giving, sharing and pooling electrons), and why salt shatters, copper bends and sugar melts on a stove.
- 7min read
- 10min listen
- 29questions
- Atoms and elements
What an atom is made of, why the number of protons decides the element, where the elements were made, and how radioactive decay can date a bone.
- 9min read
- 11min listen
- 36questions