What number when divided in half becomes zero?

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

Today is John's birthday.
A year ago, John had five candles and he lit all the candles except the one at the last.
Now he is going to light all the candles.

How old is John Today?

(He is not five today.....)

Who is generally closer to the kids, mom or dad?

(it's a funny riddle)

You have a 12 liters jug full of water. You have two empty 8 liters and 5 liters jug. How can you divide the water into two equal parts using these jugs?

Why did Buffon take the goal with him after every Juventus match?

Forwards I am heavy, backward I am not. What am I?

John was born on March 5, 1970, in Delhi, India. Jacob was born 25 days before John. The year when they took birth, Republic Day fell on Monday.

Can you find out on what day was Jacob born?

My thunder comes before the lightning; my lightning comes before clouds; my rain dries all the land it touches. What am I?

Spot 5 differences in two Christmas tree below: