| Complexity level: | 9 |
| Project cost ($): | 20 |
| Time required: | It will take an hour to set up the experiment, and an hour to conduct it |
| Material availability: | The materials required for this science experiment can be purchased at a department store. |
| Safety concerns: | Basic safety requirements. |
Hypothesis
Overview
Scientific Terms
Materials
Procedure
1. Two small slits are made in the middle of the first sheet of cardboard. The cardboard sheets are placed on the newspaper stack before they are cut. This will prevent the table from being damaged. The slit should be 1 mm x 5 mm. The slits are parallel to each other and 5mm apart. Only one slit about 1 mm x 5 mm is made in the middle of the second sheet of cardboard.
2. The experiment is set up as illustrated in figure 1. The light source is placed in front of the cardboard sheet and the whiteboard acting as the screen is placed at the back.
3. The distance between the light source and the screen is adjusted so that the diameter of the circle of light that falls on the slits is larger than the slits on the cardboard. The experiment is best performed in a dark room with the lights switched off.
4. The tests are done using the cardboards with 1 slit and 2 slits. The light patterns on the white board are observed. The distance between the white board, the cardboard and the light source are to be adjusted to obtain the best results.
Results
The results seen on the white board screen are shown in figure 2. When light passed through the cardboard with only one slit, it was diffracted. A narrow band of light, which is bright in the center and dim at the sides, was observed.
When the test was repeated using the cardboard sheet with 2 slits, light leaving both the holes were diffracted. The diffracted light from the 2 slits met and "interfered", resulting in the interference pattern of dark and light bands on the whiteboard screen. The pattern on the screen also widened by 3 to 4 times.
