getting children only makes changes to some parts?

--flora manager--

local stage = 1 --growth stage--

while true do
	wait(4)
	if script.Parent.GrowthNum.Value >= 25 and stage == 1 then
		stage = 2
		local prevchildren = script.Parent.Parent.Parent.Stage1:GetChildren()
		local nextchildren = script.Parent.Parent.Parent.Stage2:GetChildren()
		for p = 1, #prevchildren do
			if prevchildren[p]:IsA("Part") then
			prevchildren[p].Transparency = 1
			prevchildren[p].CanCollide = false
			end
		end
		for n = 1, #nextchildren do
			if nextchildren[n]:IsA("Part") then
				nextchildren[n].Transparency = 0
				nextchildren[n].CanCollide = true
			end
		end
		
	elseif script.Parent.GrowthNum.Value < 25 and stage == 1 then
		script.Parent.GrowthNum.Value = script.Parent.GrowthNum.Value + 5
	end
	
	end

no error comes up but when both for loops run, only some parts get changed. the rest are untouched. this is not desired as all parts involved should be changed.

Getting Children does not make changes to any parts, unless you change the properties.

For example,

for i,v in pairs(game.Workspace:GetChildren()) do
if v:IsA("Part") then


v.Color = Color3fromRGB(255,255,255)

end