publication date: Dec 26, 2009
the family with your scientifi
c knowledge! Snow and snowflakes
Did you know that snow is nearly all air? A whopping great 95 per cent air to be precise. This makes snow a great insulator of heat. In fact, a sheep can survive for up to 2 weeks in the snow!
A snowflake can take up to two hours to reach the ground. The heaviest will fall at one mile an hour.
According to the Guinness World Records
, the largest snowflake ever found was 38cm (15 inches) in diameter (from Fort Keogh, Montana, USA in 1887). Ice skating
The ice at ice-skating rinks is made of brine (salt water) and is usually only 2.5cm thick. The ice is kept at around -5.50°C and is made up of eight to ten layers of thin ice.
Ice skating rinks are kept smooth by a special machine called a Zamboni, which was invented in 1940 by, you guessed it, Frank Zamboni. It cleans the skate-damaged ice by shooting down water onto it which flushes the grooves deep in the ice, loosening any dirt and debris, which are then collected and discarded. It then puts down a layer of heated water, which freezes and creates a smooth new surface. Christmas candles
The earliest references to candlesticks date from 3000BC, so we know candles must be around for at least 5000 years! However, it wasn’t until the 1800s that French chemists worked out a process of combining paraffin (from crude oil) with stearic acid to produce the type of candle we know, love and mass-produce today.
20 per cent of our body-heat is lost through the head. So wrap up warm this winter and wear a hat. The hat traps a layer of air, which insulates your head. It also reflects heat from your body back to you and therefore keeps you warmer.
Find out more at www.direct.gov.uk/sciencesowhat.