What's a good advanced science project about gravity?

I am doing my paper on gravity...so my experiment should be on gravity but what in the world could I do? im in 12th grade so its got to b more challenging thatn droppping two balls off a ladder or w/e...PLEASE HELP!!!
any ideas can help me

Try this one.

How Does the Weight and Hull Shape of an Object Affect Its Sinking Rate Through Water?

PROCEDURES

1.Make 4 pyramids, 4 spheres,4 cubes and 4 cylinders.

2.Drill the core out of each shape.

3.Fill one of each shape with 30 grams of shot (shotgun shot).

4.Fill one of each shape with 60 grams of shot.

5.Fill one of each shape with 120 grams of shot.

6.Fill one of each shape with 200 grams of shot.

7.Fill all holes with same amount of glue to seal the hole.

8.Fill the tube with water almost to the top.

9.Drop all of the 30 gram shapes one at a time.

10.Record the data.

11.Drop all of the 60 gram shapes one at a time.

12.Record the data.

13.Drop all of the 120 gram shapes one at a time.

14.Record the data.

15. Drop all of the 200-gram shapes one at a time.

16.Record final data.