What does SPF stand for on sunscreen?
AnswerSun Protection Factor
SPF rates protection against sunburn-causing UV light.
Science · Facts & stats
Burn facts & stats
7 fact-checked facts about burning energy: calories, combustion and fire safety, each with the reason behind it. 5 more are in today's round and join this page after it closes.
The basics
Which gas does your body produce when it burns food for energy and you breathe out?
AnswerCarbon dioxide
Cells release carbon dioxide as they use food for energy.
Going deeper
Which type of ultraviolet light is the main cause of sunburn?
AnswerUVB
UVB mainly affects the outer skin and causes sunburn.
Which toxic gas can incomplete combustion produce?
AnswerCarbon monoxide
Without enough oxygen, fuels form carbon monoxide.
What is the chemical reaction called when a fuel burns in oxygen?
AnswerCombustion
Combustion releases heat and light.
Expert level
The fire tetrahedron adds which fourth element to the fire triangle?
AnswerA chemical chain reaction
Some extinguishing agents work by breaking this chain reaction.
Who showed that combustion involves oxygen, overturning phlogiston theory?
AnswerAntoine Lavoisier
Lavoisier's experiments in the 1770s explained burning as combining with oxygen.
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