Close your eyes and look skyward. You can probably tell where the Sun is without looking. The warmth from its rays gives away the position of this nearby star.
Imagine what would happen if you were able to concentrate the Sun’s rays. You’d produce a very bright spot. You’d also produce enough concentrated sunlight to burn through a string!
Things Required:
Plastic container
Black sewing thread
Tape
Hand lens
Nail
Pair of scissors
Directions:
Cut out a piece of 6-inch-long black thread. Tie one end of thread to a metal nail. Tape the other end of the thread to the neck of the container. The nail should hang freely in the centre of the container.
Place the container in bright sunlight. Use a hand lens to focus a beam of light on the thread. Keep the bright spot focused on the same location. What happens? Can you explain your observations?
This Is What Happens:
The hand lens focused the light rays into a very bright and hot spot. When this spot was focused on the thread, the temperature of the cotton material increased. Soon, the thread became hot enough to smoke. When enough of the fibres had burnt, the thread broke and the nail fell to the bottom of the container.
