Fastening material (clothespins / paper clips / adhesive tape)
Strong paper (e.g. construction paper, approx. 7 cm x 20 cm, approx. 130-200 g/m²)
Ruler
Support for laser (possibly height-adjustable)
Cutting surface (hard, stable)
Sheet of white paper
Instructions:
Cut a straight slit in the construction paper with the help of the knife and ruler.
The width of the slot should be about 0.1 mm.
Cut a second slit parallel to the first. Choose a distance between the slots of about 1-1.5 mm.
Attach the paper to the ruler with the fastening material and place it at a distance of about 2 m from a wall.
Set up the laser in such a way that the laser beam hits the gap in the construction paper straight at a distance of about 15 cm.
Always use the safety goggles.
Attach the sheet of paper as a screen to the point where the light beam hits the wall.
Darken the room.
Observation:
The light spot on the screen is not point-shaped, but elongated in the direction perpendicular to the columns. There are dark spots in it.
Explication:
The light is diffracted at the edges of the two columns. In addition, the light waves passing through the two fissures interfere. This leads to the dark spots, the minima of the interference figure.
Tips:
Move the laser beam back and forth slightly with the contact surface to set an optimal result.
