In the Noah’s Ark account, Noah was told to cover the Ark with pitch. Genesis 6:14 says the vessel was to be covered with pitch inside and outside, providing a waterproof coating for its wooden surfaces.
Pitch is a broad ancient term for a sticky, water-resistant substance, commonly associated with bitumen, tar, or resin. The exact material intended by the Hebrew word is not certain enough to identify one modern chemical product. Its practical purpose in the story is clear: sealing the Ark against water.
The instruction appears with the command to build the Ark from gopher wood. These are separate details: gopher wood describes the construction material, while pitch describes the protective coating. The biblical passage does not state how much pitch was needed, how it was heated, or which source supplied it. Modern reconstructions sometimes use asphalt-like sealants, but those engineering choices are not specified in Genesis.