In what brand of shampoo does a marble move the slowest?

It would be in the shampoo that has the greatest density.

Since this is not my area of expertise, I searched Google under the key words "shampoo density brand" to get this possible source:

http://shopping.yahoo.com/s:Shampoo:4575-Shampoo%20Type=Extra%20Body%20Shampoos

I hope this helps. Thanks for asking.

the movement of one object around another is