Patterns in water bacteria communities
Here are the patterns he has found:
- If a type of bacteria grows on the treatment plant filters, it usually shows up at the tap.
- Changes in the bacterial community increase as they travel along the pipes.
- As time passes the bacterial community in the pipes gets steadily different from the community at the treatment plant.
- Communities look similar at the same time of year - there's a seasonal pattern.
- How often a bacterium is found in samples is a good measure of its abundance in the whole system.
First bicycle
The oldest bicycle in the world today is sitting on a ledge on the first floor of Glasgow's Riverside Museum. It was built around 1845 by the draper Gavin Dalzell in Lesmahagow.
Pedal-driven bicycles were invented in Scotland. The first is thought to have been built in 1839, by Kirkpatrick MacMillan. He was a blacksmith in Dumfriesshire.
A human on a bike is claimed to be the most efficient creature on earth. So what does that mean?
Well efficiency is a basic idea in engineering. It's the work done by a machine divided by the energy it uses. So maximum efficiency is 100%, which means all the energy you put in comes out as useful work.
Every real-world machine has an efficiency less than that, because some of the energy is wasted, usually as heat. A motor-car loses heat to the air from the engine, the exhaust and the tyres. So depending on speed, motor-cars have an efficiency down around 20%.
A bicycle has an efficiency somewhere around 90%. And that's true even for the very earliest bikes like the one in the Riverside Museum.
But efficiency isn't everything in engineering. The first bikes had solid wheels and saddles, no chain, no gears and no suspension. Take a close look next time you're in the Riverside Museum.
How far do you think you could comfortably travel on that old bicycle?
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Learn more about energy efficiency.
Science of bicycles.
Aircraft pioneer
Percy Pilcher might have been the first man to make a powered flight in a heavier-than-air craft. If he had lived. Percy came to Glasgow as an engineering apprentice at the age of 20, after seven years in the Royal Navy.
"He started building glider models in his Byres Road flat," says Riverside Museum curator Neil Johnson-Symington. "He made such a racket that his landlady kicked him out."
But the bug had bitten Percy. As an engineering lecturer at Glasgow University, he began to build and test gliders - the Bat, the Beetle, the Gull and the Hawk.
He flew the Bat successfully at Cardross, during summer 1895, becoming the first person to make repeated heavier than air flights in Britain.
Percy's goal was always powered flight. So he had to figure out how to fit an engine to his gliders. The science sounds simple.
Four forces act on anything in flight. Thrust tries to speed it up. Drag from the air slows it down. Lift from the wings raises it. Weight pulls it back to earth.
To keep a steady height, lift must equal weight. They need to be balanced forces. For a steady speed, thrust must equal drag.
But the engineering is tricky. The problem for pioneers like Percy was getting enough lift. Attach an engine to a glider and it becomes a lot heavier. So more lift is needed. Which means much bigger wings.
With the materials and methods of the time, Percy could not make big wings strong enough.
The solution was to stack wings on top of each other to make biplanes and even triplanes. That gives lots of lift from strong, stubby wings.
Percy was almost there. He had built a triplane. He had formed a company to make the engines. He had arranged a demonstration to money men in late September 1899. But the day went badly wrong.
The tail of his trusty Hawk broke and Percy Pilcher plummeted to earth. He died two days later, the first Briton to lose his life in pursuit of powered flight.
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Steam on the road
At first no one knew that motor cars would one day run on petrol. At the beginning of the 20th century, a lot more of them ran on steam. The best-selling steam cars were made by the twin brothers Francis and Freelan Stanley. "They were teachers turned inventors," says Glasgow Museum's Neil Johnson-Symington. "They were wizards of self-promotion."
Steam cars were easy to drive, he says, because they did not need a clutch or gears. "They held the land speed record for 4 years in a row. They were reliable, quiet and fast."
But there was a downside. "It took 25 minutes to start the engine. And you had to stop every 50 kilometres to fill up with water."
A steam engine is an external combustion engine. That means the fuel is burnt in a container separate from the water, which it heats to make steam to drive a piston.
A petrol engine is an internal combustion engine. That means the burning fuel creates hot gases that drive the piston directly.
For the same power a petrol engine can be smaller and lighter than a steam engine. Mainly because it doesn't need a separate boiler, condenser and water supply. Then there's the question of cost, says Mr Johnson-Symington.
"Stanley steam cars were hand-built using traditional skills. But these methods were becoming out of date. In 1914 Stanley made 650 cars. That's how many the Ford Motor Company built in one day.
"In the end the steam car could not compete with Henry Ford's mass-produced petrol cars."
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Steam on the rails
Glen Douglas is a locomotive that used to steam at speed along the West Highland line. Now she stands tall and still in Glasgow's Riverside Museum.
"Glen Douglas was designed to pull carriages up steep hills and around tight bends, in all kinds of weather," says Neil Johnson-Symington. He is Glasgow Museums' curator for transport and technology.
"The route runs from Glasgow to Fort William and on to Mallaig, passing lochs, moors and mountains. It is one of Scotland's most scenic and demanding routes. Glen Douglas worked it for more than 20 years."
Steam locos, such as Glen Douglas, run on coal and water. They burn the coal to heat the water to make the steam to drive the engine to make the wheels go round.
"It took two men to run a steam locomotive," says Mr Johnson-Symington. "Both were skilled jobs. Before departure the fireman inspected the boiler and the fire buckets. The driver oiled the engine and double-checked everything."
The journey was teamwork too, he says. "The fireman shovelled coal - little and often - into the fire, heating the water in the boiler. The driver used the steam to power the engine."
"It's the railway that takes Harry Potter to Hogwarts."
Thanks to Haworth Village website for the locomotive animation.
Curiosity Rover
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