What are some good science experiments I can do at home to increase my son's understanding and love for science?

Every step of a man is governed by a science rule. Authors have compiled a lot of books and other stuff on this subject. Few of these are; germination of a seed, volcano model, oxygen needed in burning, etc.

sinking and floating using a glass box full of water

The best way is to observe closely everything around you from scientific standpoint.

Be curious because everything is harboring science in it.

Second you should watch chemistry, physics and other sciences experiments on video webs.

you can mix milk with coca cola and you see what happen he will ile it 

you can immitate the volcano erruption and the lava using clay and any soda juice children will love it and you can find it on the net. Other simple and fun sience experiment is to show him how different objects sink in water while he is swimming or playing with water. 

you could experience vegetable's growth and species  developments using water .it is safe and secure experiments and easily understanded by youngers.

there is is a lot's of science experiments tat you can make at homeit depends also of your sons age like:

- The commutator is needed to produce direct current. When a loop of wire rotates in a magnetic field, the potential induced in it reverses with each half turn, generating an alternating current. 

or the opposite making magnetic field by electricity

thanks for invitation

match the science with shape of trees, animals ,...

There is a facebook page called Cafe Scientifique Dubai. They have lots of interesting information and links for all sorts of things , for both adults and kids. They also organise star gazing trips sometimes.  If you keep an eye on that I am sure you find some things of interest for your son

Scientifique