Stuff for water PP

So Mari showed me this site the other day and since my group decided to each do one topic since we had to do three i chose to do the Mpemba effect.

http://www.btinternet.com/~martin.chaplin/explan.html#158





The Mpemba Effect

Which pretty much is that hot water sometimes freezes faster than cold water.

This has dated back to 4th century BC by Aristotle.

Erasto Mpemba who was at school at Iringa School, Tanzania also found this to be true when he said that he could freeze ice cream faster if he warmed it first.

one experiment tried was with 90 degrees Celsius water freezes faster than 18 degrees Celsius

that the degree of supercooling is greater in initally cold water than in initally hot water. hot water freezes at a higher tempeture. when you freeze hot water there is little amounts of water in the frozen piece that don't freeze when with cold water it all freezes therefore it takes longer.

a lower temperture allows a faster crystal growth rate