Done By:1) Lee Cheok Feng2) Benjamin Lim3) Tan Xue Liang4) Andre Ng

1. How was metal discovered?1. How was metal discovered?

Metal was known to ancient man before Metal was known to ancient man before writing.writing.

It was discovered by accident but nobody It was discovered by accident but nobody knows who exactly found it.knows who exactly found it.

In the past it was used to make weapons.In the past it was used to make weapons.

Now it is use to make a lot of things . For Now it is use to make a lot of things . For example it is used to make coins and oven .example it is used to make coins and oven .

Solid at room temperature Good conductors of heat and

electricity Malleable and ductile Are usually shiny

Different types of metals Aluminum Copper Gold Iron Nickel Sliver Steel Tin Zinc

Plastic is a common name for Polymers (po-ly-mars) materials made of long strings of carbon and other elements.

Each unit in a string is called a monomer (mo-no-mar), and is a chemical usually derived from oil.

The early history of plastic and how The early history of plastic and how was it used for in the past& presentwas it used for in the past& present• The first man-made plastic was invented

by Alexander Parkes in 1862,in the USA, he called this plastic Parkesine.

• Now it is used for water bottles, food containers, pipes, measuring jars and also in CD’s!

• In the past, it was used for dentures, replacement for ivory, tortoise-shell, and bone , for movie films, ping-pong balls etc

Anything made from plastics were Anything made from plastics were considered cheap 40 years ago.considered cheap 40 years ago.

The first synthetic plastic was made The first synthetic plastic was made from the plant material cellulose in from the plant material cellulose in 1869.1869.

Petroleum is the main source of Petroleum is the main source of making today’s plastic. making today’s plastic.

How Plastics Are MadeHow Plastics Are Made

Characteristics ofPlastic

Hard and slippery Soft and rubbery Tough and slippery Flexible Good insulators of heat or electricity Light weight Hygienic Non-rusting Easy to shape and colour Cheap

ResourcesResources http://www.wikianswers.com http://www.reachoutmichigan.org/funexperiments

/quick/plastic.html

http://www.enotes.com/science-fact-finder/metals-other-materials/when-was-plastic-first-invented

http://en.wikipedia.org/wiki/Plastic http://www.ec.gc.ca/cleanair-airpur/Metals_and_th

eir_uses-WSF43DE7D3-1_En.htm

History of Plastics - Plastic Recycling and the Environment

Q&A Session!

Any Questions?

THE END!!!

Thank You for Your Attention!