Comparing water repelling products
The materials required for our science fair project:
- 2 glass sheets (suggested size 20cm x 20cm) or plates
- 1 bottle of Rain-X
- 1 bottle of Aquapel
- 1 wooden block (40mm x 100mm x 200mm)
- 1 marker pen
- 1 eye-dropper
- 1 beaker of water
- 1 ruler
- 1 stopwatch
- 1 protractor
- 1 piece of cloth
1. For this science fair project, the independent variable is the angle at which the glass is slanted and the brand of water repellent used. The dependent variable is the time taken by the water to flow 10 cm down the surface of the glass sheets. The constants (control variables) are the smoothness of the glass surface, the distance the water droplet travels and the room temperature.
2. Two glass sheets are marked “Rain-X” and “Aquapel” with the black marker pen. The water repellent solutions are wiped on the glass surface using a piece of cloth. The brand of the water repellent solution used on the glass surface should match with the marking.
3. Using the marker pen and a ruler, 2 lines 10cm apart are drawn on the 2 glass sheets. These 2 lines l represent the start and finish lines for the water droplet to travel.
4. The glass sheet marked Rain-X will be tested first. Using the wooden block and the protractor, the glass sheet is made to rest at a slanted position. The plate will be slanted at 15 degrees to the table surface. The angle will be confirmed using a protractor. The 2 lines drawn earlier should be horizontal to the table surface.
5. The eye-dropper is used to place a drop of water on the upper line of the glass surface. The stopwatch is started and the time taken by the droplet to travel to the bottom line is measured. The result is recorded in the table given below.
6. Procedures 4 and 5 are repeated at 30 degrees, 45 degrees, 60 degrees and 75 degrees. All the measured times are recorded in the table given below.
7. Procedures 4, 5 and 6 are repeated using the glass coated with Aquapel solution. All results are recorded in the table given below.
Handle glass carefully - wear protective gloves