How does the weight afectt the way a ball roll?

Hi everyone! I'm back to a new episode of.... Science for 6th grade!!! And today our guiding question is.... How does the weight affect the way a ball roll? What we did in the experiment was that we took balls of different size and weight, after we shows one and putt it on the edge of a table and by blowing in a straw we tried to make the ball move. Then we wrote in our notebook if the ball was easy to move, or hard, if the ball moved  fast, or slow and finally how the ball moved, straight, turned to the left, turned to the right. So here is what I got:

LITTLE PEBBLE

•  It was easy to move
• It rolled pretty fast
• But it rolled in a diagonal line.

Big pebble

• pretty hard to move
• moved slowly
• went straight then turned

Tennis ball

• Very hard to move
• Very slow
• But moved straight

golf ball

• very hard to move
• very slow 
• moved a litle diagonaly

Can you see that the heavier the material is the slower it goes the harder it is to move but the straighter it goes? This is what I discovered in science today.
See you!!!