Why do penny-farthings have one big wheel?

Why did penny-farthings have such big wheels?

The larger the wheel in this early design of bike, the faster the rider could go, as the pedals were directly connected to the wheel without any gearing mechanism. The only way to make the bicycle travel further for each turn of the pedal was to enlarge the wheel to which the pedals were connected. This did make for some difficult bikes to ride, though, and the design was soon replaced by smaller models with gearing mechanisms.

Who was the first person to wear a watch?

The first known recorded wristwatch was made by two Swiss men, Jaquet-Droz and Leschot, in Geneva in 1790. It was a “watch to be fixed to a bracelet”. The earliest surviving example is from 1806.

Who invented the fountain pen?

When pens were first invented, the nib had to be frequently dipped into a container of ink. This slowed down the process of writing considerably. As a result several people had the idea of creating a pen where the reserve of ink was attached to the pen. The first working version of such a pen was patented by LE Waterman in 1884, in the United States.

Who invented the light bulb?

In 1845, J Starr, an inventor in the United States, suggested using a filament of carbon as an electricity conductor enclosed in a glass bulb to produce light. In 1878, Joseph Swan, from Britain, developed a vacuum pump to remove air from the bulb so that the filament would not oxidise and burn away, but it wasn’t until 1879 that Thomas Edison (of America) patented the world’s first electric light bulb. Edison’s bulb burned for 13.5 hours before it went out. However, Joseph Swan, from Sunderland, was the first to demonstrate an electric light bulb in December 1878 – shortly before Edison. He just didn’t get round to patenting it.

Where does the word “magnet” come from?

Ancient Greeks first found magnetic rocks in an area called Magnesia, in what is now Turkey – hence “magnet”.

Who performed the first heart transplant?

Christiaan Barnard, a South African, performed the first heart transplant in 1967. His patient lived for only 18 days, but thanks to his work, many heart transplants are performed all over the world every year.

Why does a helium balloon pop at a certain height?

The helium gas exerts a certain pressure on the balloon from the inside. The pressure, or push of the gas molecules on the inside will be equal to the pressure on the outside of the balloon, otherwise the balloon would squish or expand. As the balloon gets higher in the sky the air pressure surrounding it decreases, resulting in a higher pressure on the inside. This means the gas molecules on the inside are pushing more on the balloon. The balloon is not infinitely elastic, so once pushed beyond its limit, it pops.

What is white spirit made of?

It is a mixture of spirits produced by heating petroleum – itself a mixture of hundreds of organic compounds with boiling points varying between 115C and 180C. In this temperature range, various compounds vaporise, and can be collected and used. Boiling a substance at different temperatures to give different products is called fractionation.