Double-walled pipe

Imagine you have a straw that has another straw inside it. That's like double-walled pipe! Double-walled pipes are used to transport things like oil or gas from one place to another.

The outer straw in the double-walled pipe is the first layer of protection. It keeps the harmful substance inside the pipe and prevents leaks. The inner straw is the second layer of protection. It's there to catch any leaks from the outer straw and prevent them from getting out.

Now, if there is a leak in the outer straw, the inner straw will catch the substance and prevent it from causing harm to the environment or people. This way, double-walled pipes provide extra safety and peace of mind that the harmful substance won't escape into the soil or air.

Just like how you should always have a helmet on when riding a bike, it's always good to have double protection when transporting things that can be harmful.