Question

you left a receipt on a desk. you decide to eat lunch at your desk, and you set your hot plate on top of the receipt. when you pick up your plate, you notice that the receipt has turned black. what likely happened to the receipt?

Explanation:

Identify the printing technology used for receipts

Most standard retail receipts are printed on thermal paper using direct thermal printing technology, which does not use ink or toner.

Analyze the effect of heat on thermal paper

Thermal paper is coated with a heat-sensitive chemical layer (containing a dye and an acid developer). When heat is applied, these chemicals react and turn black to form the printed text or image.

Determine the cause of the receipt turning black

Placing a hot plate directly on top of the receipt transferred high heat across the paper's surface, triggering the chemical reaction across the entire heated area and turning the receipt black.

Answer:

The receipt was printed on thermal paper (using direct thermal printing technology). When the hot plate was placed on top of it, the heat triggered the heat-sensitive chemical coating on the paper, causing it to react and turn black.