How It Works - UK (2020-02)

086 HowIt Works http://www.howitworksdaily.com

NicholasFoster

n Metalsaltsandtinymetalparticleshave

colouredstainedglassforthousandsofyears.

Formetalparticles,thisusestheelectron

movementthatmakesmetalsusefulasw ires.

Electronsatmetalsurfacestrapsomecolours

oflightandreflectothers.Mostlargemetal

sheetsreflectallv isiblecolours,sotheshiny

surfacesworkasmirrors.Smallermetal

particlestrapandreflectv isiblecolours.Aswell

asbeautifulstainedglass,thiscausesstrange

effects.TheLycurgusCup,a greenglassgoblet

from4th-centur yRomeheldintheBritish

MuseuminLondon,looksredwhena lightis

putinsideit.AE

What is usedto colour

stained-glass windows?

GrahamBlythe

n Sunlightbendswhenit shinesthrough

raindrops.Itsplitsupintocoloursandcreatesa

rainbow.Iflightisreflectedbya droplett w icea

faintmirrorimageappearsovertheoriginal

rainbow– itscoloursareinverted.AG

How do double

rainbows occur?

h Patel

e NASAwebsitehasperpetrateda fewApril

• forexamplethattheMoonismadeof
  cheese,orthatMarsispronetohumourbecause
  ofitslowgrav it y.AM

arsReconnaissanceOrbitersnappedthis

-facedcrateronMars

© NASA

Louise Keys

n A preser ved organism must beat

least 10,000 years old before it canbe

considered a fossil. A ny thing younger

than that w ill not be accepted by

most palaeontologists. JE

How old is

the youngest

fossil?

© Getty

romgreentore wen

© Alamy light shines through it

© Getty