91色情片

Water wheels

6 July 2005

When driving a speedboat, why don鈥檛 you have to change gear when you change speed, as you do in a car?

Graham Lundegaard, Gloucester, UK

Topics: Last Word

More from New Scientist

Explore the latest news, articles and features

A light micrograph showing the neurons of a mouse. The neurons have been labelled with green fluorescent protein to distinguish between cells at different depths within the brain tissue (blue is deepest and green is shallowest)

Mind

‘Remarkable’ discovery upends our understanding of how brains store memories

Boudica Leading Rebellion, 60 AD

Humans

DNA reveals a society organised around women in pre-Roman Britain

Graeco-Latin squares

Physics

Quantum entanglement is key to solving 250-year-old maths problem

Space

The most breathtaking photos of the total solar eclipse

Popular articles

Trending New Scientist articles

The shock revelation that light bulbs are wrecking your metabolism

How ancient trees are warning us about the next enormous solar storm

‘Remarkable’ discovery upends our understanding of how brains store memories

DNA reveals a society organised around women in pre-Roman Britain

The proton is more quantum than we thought

The 85-million-year timeline of human evolution

Denisovans may have dwarfed other ancient humans

The most breathtaking photos of the total solar eclipse

Fate of the AMOC may depend on how quickly CO2 rises聽

Mammal ancestors were giving birth to live young 236 million years ago