Hour glass tutorial

Hello - Sorry to cross post but I think I put in wrong group

I'm doing the hour glass tutorial and I'm having a problem with the animation.
When I press play the sand shows up as snow(which is not so much the problem
right now I think I know how to change it do a sand substance however the snow
won't change from its original color of white to the sand color when I press
"Assign Material to Selection. It remaiins white snowflakes. Here is a link
to show you my interface as is right now.

http://i215.photobucket.com/albums/cc10/Spookie71/snow.jpg

Any Ideas on how to change the colour of the animation of snow too a sandy