52 | New Scientist | 28 September 2019
The back pages Puzzles
Quick crossword #41 Set by Richard Smyth Quick quiz #22 Puzzle set by Rob Eastaway
#23 Circling the squares
Darts player Juan Andred has noticed that
on a standard dartboard, there are some
neighbouring pairs of numbers that add
up to a square number. For example, 20
and 5 make 25, while 6 and 10 add up
to 16. He has been wondering if he can
come up with a new arrangement of the
numbers 1 to 20 so that all neighbouring
pairs add up to a square number. And he
has nearly succeeded.
He has 20 at the top of the board,
and every pair of neighbours adds to a
square - with one exception. On his new
board, 18 doesn’t form a square with its
clockwise neighbour, which is 15, or with
its anticlockwise neighbour.
What does Juan’s “square” dartboard
look like?
Answer next week
#22 The 9-minute egg
Solution
The slow method for boiling an egg for 9
minutes: start the 7-minute and 4-minute
egg timers. When the 4 runs out, flip it. When
the 7 runs out, there is 1 minute left in the 4.
Put the egg on. When the 4 runs out (after
1 minute), flip it. When it runs out, flip it again
to get 9 minutes. This means I won’t get my
egg for 7+9=16 minutes.
Fast method: Start timers 7 and 4 and
put the egg on. When 4 runs out (elapsed
time 4 minutes), flip it. When 7 runs out
(after 7 minutes) flip it. When 4 runs out
again (elapsed time 8 minutes), flip the 7.
When the 7 runs out (total 9 minutes), the
egg is cooked. So I get my egg in 9 minutes.
1 The male sperm whale
has the largest what of
any animal on the planet?
2 Marie Curie (1903),
Maria Goeppert Mayer
(1963). What name and
year come next?
3 Which element makes
stainless steel stainless?
4 What were Tiangong-1
and Tiangong-2?
5 ARCT, GFST and MEDI
are three examples of the
56 four-letter Longhurst
codes used by earth
scientists to refer to what?
Answers below
Cryptic
Crossword #15
Answers
ACROSS 1 Rebuke, 4 Ice bag,
9 Pasteur, 10 Lardo, 11 Ad hoc,
12 Traffic, 13 Hippocampus,
18 Fractal, 20 Tacit, 22 Veins,
23 Tagging, 24 Regard,
25 Enigma
DOWN 1 Repeal, 2 Bosch,
3 Kneecap, 5 Cilia, 6 Bird flu,
7 G-force, 8 Criticality,
14 Imaging, 15 Mutagen,
16 Q fever, 17 Stigma,
19 Taser, 21 Cling
Quick quiz #22
Answers
Brain 1
Donna Strickland (2018). 2
an to She was the third wom
win the Nobel prize in physics
uminim , at a mium Chrom 3
ass of 10.5 per cent by m
Chinese space stations, 4
orbiting 2011-2018 and
e 2016-2019. The nam
eans “heavenly palace”m
Sea areas with distinctive 5
ical conditions: biogeochem
here, the Atlantic Arctic, the Gulf
and the MediterraneanStream
ACROSS
8 Height (8)
9 More proximate (6)
10 Device facilitating rotation
around a fixed axis (10)
11 H 2 SO 4 or HNO 3 , say (4)
12 County noted for its
Jurassic geology (6)
14 Parts of the auricles (8)
15 Flightless bird,
Struthio camelus (7)
17 Inability to process
sensory data (7)
20 Rb (8)
22 Crack; interpret (6)
24 Jaeger (4)
25 Deprived of O (10)
27 Elastic coil that stores
mechanical energy (6)
28 Sent digital data to a
remote system (8)
Answers and the next quick crossword next week.
DOWN
1 Proportion of sunlight
diffusely reflected by a
planetary surface (6)
2 Approximately 568ml (4)
3 ___ spectrum, range of
neurodevelopmental
disorders (8)
4 Earwax (7)
5 Not in neutral (2,4)
6 Geologic era that began
541 million years ago (10)
7 Thiamine deficiency (8)
13 CH 3 (CH) 4 CO 2 H (6,4)
16 Foul-smelling
Florida cryptid (5,3)
18 Kaiju unveiled in 1954 (8)
19 Clot (for example) (7)
21 Blue dye (6)
23 Rudolf ___, mechanical
engineer (6)
26 Large-screen
cinema system (4)
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