A candle is a stick of wax with a string called a wick running through its center that produces light when you burn it. Before electric lights were invented, candles were one of the main ways people lit their homes after dark. They'd place candles in holders around rooms, carry them up staircases, and set them on tables for family dinners.

The wick is what actually burns, but it needs the wax around it. As the flame melts the wax near the top, the liquid wax soaks into the wick and fuels the fire, creating a steady, gentle light. A single candle might burn for hours, slowly getting shorter as the wax melts away.

Today, people use candles more for atmosphere than necessity. Birthday cakes have candles you blow out while making a wish. Families might light candles during holiday celebrations or place them around the house to create a cozy feeling. Some candles are scented, filling a room with smells like vanilla or pine.

You might hear someone say they're “burning the candle at both ends,” which means they're staying up too late and waking up too early, exhausting themselves, like a candle lit at both ends would burn out twice as fast.