Water Bottles

I was looking in the DIY section and seen a incubator made from a cooler.Water bottles were put in the cooler directly on the heat tape.What is this purpose? a I am making a incubator from a refrigerator do I need water bottles?
Thanks.Mike

I'm not sure. But our incubator we purchased, and it's definitely made from a cooler. I can't wait to test it out.

I have seen in other posts that they use the water bottles to keep a steady temperature. I do not use any in my incubator but mine is not a cooler so maybe it works different.

Whether its a cooler or a normal incubator placing water bottles in it will help keep your temps stable. Water is much more stable than air at holding temperatures so thats why people try to fill up empty bator space with them.

To distribute the heat evenly

Water also holds heat better and longer than air does...so, if for some reason you have a power outage, the incubator in theory should stay warmer longer than it would without the water bottles. Mostly I think it's to regulate temperature though; the water bottles aren't going anywhere, but when you open the incubator, all the hot air comes rushing out, replaced by cooler air.