For procedural scaling, you can use the interpolation parameters of the Scale operator.
In this scene I start by scaling particles to zero in one Scale operator on their birth frame, then in a second Scale operator I scale them up to 500% over 20 frames using the interpolation parameters (timing in this operator is set to continuous). Finally using a time test I send them to another event after 50 frames and scale them down using the same interpolation settings.
In this scene I start by scaling particles to zero in one Scale operator on their birth frame, then in a second Scale operator I scale them up to 500% over 20 frames using the interpolation parameters (timing in this operator is set to continuous). Finally using a time test I send them to another event after 50 frames and scale them down using the same interpolation settings.