How to correctly use BodyPosition?

Alright so here's what I have so far. I have bricks, called "Rainbow Bricks", located in a PartStorage model in the workspace. I'm trying to build a circular conveyor belt, with everything that lands on it going towards the middle. I think the easiest way to do that is to make the center part of the conveyor, the collector, have some sort of black hole script to pull only those certain bricks in towards it. Now here's what I know

if object is rainbow brick, then add it into a table
if the relative position (collector position - part position) is less than 25 then
insert a BodyPosition into the children with less than 25 relPos
BodyPosition.position = collector.position
BodyPosition.maxForce = x

Seems simple enough, right? Well here's my attempt

local hole = script.Parent
local childList = {}

function checkObject(obj)
    if (obj ~= hole) and (obj.className == "Part") and obj.Name=="Rainbow Brick" then
        if (obj.Anchored == false) then
            table.insert(childList, 1, obj)
        end
end

checkObject(workspace)

    local child = childList[n]
    if (child ~= hole) and (child.className == "Part") and (child.Anchored == false) and (child.Name=="Rainbow Brick") then
        local relPos = hole.Position - child.Position
        local motivator = child:FindFirstChild("BlackHole Influence")
        if relPos.magnitude < 25 then
                if motivator == nil then
                    motivator = Instance.new("BodyPosition")
                    motivator.Parent = child
                    motivator.Name = "BlackHole Influence"
                end
                motivator.position = hole.Position
                motivator.maxForce = 200
            end
        elseif child.motivator ~= nil then
            child.motivator:Remove()
        end
    end
end


-- 

No errors in the output, nothing is happening. I'm sorry if this script is terrible. I'm still a beginner.