Air pressure question...?

Question

A round-bottom flask with 1/4 water in it is heated. A glass tube is inserted in the flask with a cork to cover the opening of the flask, which is then inverted with the glass tube end inserted into a beaker of colored water.

( I redrew it on Paint and uploaded it here: http://img127.imageshack.us/img127/2936/airpressureel0.jpg )

1. State the reason for heating the flask.

2. State your observation when the flask is inverted with the glass tube end inserted in the colored water.

3. Give a reason for your answer in (2)

Please help me answer this! I have no CLUE what so ever!!

Answer 1

to keep warm all are changed onto colours  

Answer 2

1 When you heat the partially filled flask you drive out the air and replace it with water vapour

2) You invert and place the glass tube into the coloured water. After a short time the coloured water is drawn up the glass tube into the flask.

3. The coloured liquid is drawn up because the water vapour in the flask cools, condenses and results in a low pressure in the flask. This low pressure sucks up the coloured liquid which is actually pushed up by the air pressure on the coloured liquid.