Test deck
Five easy cards for tests and previews. Seeded locally, in CI and on staging, never in production.
5 cards · Science
Each Zap teaches up to 5 new cards, so you learn the deck a few at a time.
Checked by the Brain Zap team · reviewed 4 Oct 2026
Preview
H₂O
Show answerHide answer: H₂O
Water
NaCl
Show answerHide answer: NaCl
Table salt
O₂
Show answerHide answer: O₂
Oxygen
CO₂
Show answerHide answer: CO₂
Carbon dioxide
Au
Show answerHide answer: Au
Gold
All 5 cards
H₂O
Water
NaCl
Table salt
O₂
Oxygen
CO₂
Carbon dioxide
Au
Gold
More science decks
Human body
Bones, organs, blood and cells: 40 facts about how the human body is built and how it works, from the skeleton to DNA.
40 cards · meet them all in 8 days
About 2 min a day
Sample: Chemical elements
Symbols of common chemical elements, a short sample deck with a few easy cards.
5 cards · meet them all in 1 day
About 1 min a day
Sample: Planets
The planets of the solar system, a short sample deck to try the science category.
5 cards · meet them all in 1 day
About 1 min a day