New Scientist - USA (2020-10-24)

24 October 2020 | New Scientist | 55

Tom Gauld

for New Scientist

Answers

sinuses, located behind the eyes,

leads to a more diffuse headache

that can be felt in the front or the

back of the skull.

A “splitting” headache with pain

behind and between the eyes that

radiates to the forehead occurs

due to congestion in the ethmoid

sinuses, which are found between

the nose and eyes.

Tension or stress headaches are

other common types. The location

of the pain depends on which

muscle group in the head and neck

is sending signals that the brain

interprets as pain. This kind of

headache can result from poor

posture or anxiety (as emotional

stress has a physical effect), or

a vicious circle involving both.

This happens when adrenaline

released by the body to help

cope with stress causes throbbing

pain due to over-dilation of the

blood vessels in the brain.

The type of pain experienced

and its location can help unlock

the mystery of why you got it, and

allow you to take steps to fix it.

Cycle logic

A triplet bike is lighter and has less

resistance per person, so is more

efficient than a tandem, which is

more efficient than a regular bike.

Does this trend hold however long

the bike? (continued)

Hilary Johnston

Perth, Western Australia

At a cycling event in Perth 30 years

ago, a group of men brought out a

10-seater bike.

Despite much sprinting

with the bike to gain enough

speed to jump on and start

pedalling, the men never

successfully rode it because the

minimum speed to maintain

balance couldn’t be reached. It

proved impossible to keep the

centre of gravity under the

cyclists on such a long bike.

Jerry Shiner

Toronto, Canada

Any useful gains in the ratios

between riders, bicycle, air or

mechanical resistance would

become more limited with each

extra rider, soon becoming so

minuscule as to be meaningless.

Mike Follows

Sutton Coldfield, West Midlands, UK

Intuition suggests that tandems

and triples should be more

efficient because of the slipstream

benefit for the rear riders and the

smaller mass of machine per rider.

However, the men’s tandem world

record for 1000 metres is only just

faster than that for a regular bike.

Time trials on UK roads show

that there would usually be a close

finish in a men’s race between a

regular bike and a tandem over

distances of 10 to 100 miles, and

that women riding solo should

consistently beat a tandem.

Tandem racing ceased as an

Olympic event after 1972, but

continues at the Paralympics,

with an athlete with a visual

impairment in the rear seat. ❚

Quick quiz #74

Answer

1 Mae Jemison

2 Blood plasma

3 George Washington Carver

4 Termite

5 Leprosy

Cryptic crossword

#42 Answers

ACROSS 7 Dolly the sheep,

8/11 Maillard reaction, 9 Rook,

10 Crampon, 12 Resin,

14 Match, 16 Accrete, 19 Stun,

20 Appetite, 22 Doppler effect

DOWN 1 Soda, 2 Slalom,

3 Ethanol, 4 Veldt, 5 Charge,

6 Keto diet, 13 Scupper,

15 Canopy, 17 Ratify,

18 Raven, 7 Tick

#81 A bridge too far

Solution

Tom can take 9 minutes to

cross the bridge and the group

can still cross in 17 minutes.

Call the four students A, B, Tom

and Tim. If A takes 1 minute

and B takes 2 minutes then:

A and B cross (2 minutes),

A returns (1 minute),

Tom and Tim cross (10 minutes),

B returns (2 minutes),

A and B cross (2 minutes).

From this it can be seen that

Tom can take 9 minutes and

not affect the total time.

“ Intuition suggests

tandems are more

efficient, but time

trials show that solo

female riders usually

beat tandem riders”