This document discusses several important inventions and their inventors. It describes how the Greeks invented alphabets in the 11th century and how the Phoenicians later refined them. It notes that Alexander Bain invented the clock in the 1840s as an engineer in Scotland. Anastasio Volta invented the first battery, called the voltaic pile, in 1800 in Italy using copper and zinc discs. Edward Jenner invented vaccines in 1796 in England to stimulate immunity without contracting diseases. Other inventions discussed include the air conditioner by Willis Carrier in 1902, the electric traffic light by Lester Wire in 1902, the microwave oven by Percy Spencer in 1945, and the USB flash drive by Pua Khein-S

1. UNKNOWN INVENTORS?

2.  There were many scientist in world ……but we
know only some of them.
 So today we are going to know about great
persons behind the great invention
So lets beginn……………

3. #1 Alphabets
 these invention was
done by greeks in
11th centuary .
 Later on it was
polished by
phoniceans.

4. #2 CLOCK
 Alexzander bain was the
first person who invented
the clock in 1840’s.
 He was an engineer by
profession.
 Bain's first patent was
dated 11 January 1841,
and was in the names of
John Barwise,
chronometer maker, and
Alexander Bain,
mechanist.
 It describes his electric
clock which uses
a pendulum kept moving
by electromagnetic
impulses.

5. #3 BATTERY
 Anastasio Volta was
the first who battery in
1800 in italy.
 In 1800 volta invented
the first true battery
called volatic pile.
 the volatic pile
constited of pair of
copper and zinc disc
piled up together.

6. #4 VACCINES
 Vaccines were invented
by edward jenner in
1796 in england
 A vaccine is a medical
mixture of weakened or
dead forms of a
disease-causing
microbe.
 These agents can
stimulate the human
body’s immune system
to develop antibodies
against the disease
without first
contracting it .

8. #4 AIR CONDITIONER
 Air conditioner was invented by willis
carrier in 1902 in US.

9. #5 TRAFFIC LIGHT
 The first electric traffic light
was discovered by lester wire
in 1902 in US .
 Prior to electricity, the concept
of a traffic signal was based
on semaphore arms and gas
lights for night driving.
 On October 4, 1912, Lester
Wire invented the electric
traffic light. It had red and
green lights and a buzzer to
warn of color shifts.

10. #6 MICROWAVE OVEN
 Percy lebnon was the one who
invented microwave in 1945.
 The microwave oven is a
cooking apparatus used to heat
food by polarizing its molecules
with electromagnetic radiation,
known as dielectric heating.
 Percy Spencer invented the first
microwave oven in 1945.

11. #7 PEN DRIVE
 Pua Khein-Seng is
the one who
invented pendrive
in 2000 in china .

12. Thank you…….