Why doesn't this change the rate of my particle emitter?

function onTouch(part) 
    local humanoid = part.Parent:FindFirstChild("Humanoid") 
    if (humanoid ~= nil) then   
        script.Parent.CFrame = CFrame.new(-5233, 0.5, 129)
        local found = workspace["ModelWithParticleEmitter"]:FindFirstChild("Part")
        if found then
            local particle = found:FindFirstChild("ParticleEmitter")
            if particle then
                particle.Rate = 20000
            end
        end
    end 
end

script.Parent.Touched:connect(onTouch)

I can't figure out why "particle.Rate = 20000" doesn't change the rate of the particle emitter