if there are small spheres on a bowl and if a straw comes near the bowl the spheres should get sucked into the straw. Or particles getting sucked by a straw. If anybody knows how to do this please help.
This question really isn't very well formulated.
Still, there isn't a built-in function for that. What you could use is the physics engine + a mesh collider.
Make a mesh collider(invisible one!) in the shape of a funnel next to the end of the straw. The purpose of that is to prevent the balls from going up without going inside the straw.
With a script AddRelativeForce to each of the balls in the direction of the end of the straw. (Of course, the balls should have the RigidBody component)
Test & tweak until your results are satisfying :)
new to unity 3d. Can you help with the script? Add Relative Force