Physics

=Ideas for Physics about what to do about water:=

Research Question: How does the refractive index of water depend on its pollution level?

Refractive index tells you how much a beam of light will bend when it enters another medium. We could collect about 8 different samples of water and have the chemists to measure the "pollution level" and I'll measure the refractive index of each sample of water. I can make a graph to see if there is any correlation between pollution level and refractive index.

Data:

Table 1 (angle of incidence and angle of refraction for 8 different samples):

Table 2 (Refractive index for 8 different samples):
 * |||||||||| Incident angle ||
 * ^  || 16.0 || 25.5 || 32.5 || 42.0 || 51.5 ||
 * Refraction angle || Sample 1 || 12.5 || 20.0 || 25.0 || 31.0 || 35.5 ||
 * ^  || Sample 2 || 13.0 || 20.0 || 24.5 || 30.5 || 36.0 ||
 * ^  || Sample 3 || 12.0 || 20.0 || 24.5 || 31.0 || 36.5 ||
 * ^  || Sample 4 || 13.0 || 18.5 || 24.0 || 31.0 || 36.0 ||
 * ^  || Sample 5 || 12.5 || 19.5 || 24.5 || 30.0 || 37.0 ||
 * ^  || Sample 6 || 13.0 || 19.5 || 24.0 || 31.5 || 35.5 ||
 * ^  || Sample 7 || 12.0 || 18.5 || 24.0 || 31.0 || 37.5 ||
 * ^  || Sample 8 || 11.0 || 18.5 || 24.0 || 29.5 || 38.0 ||
 * |||||||||| Refractive Index || Average || Uncertainty ||
 * Sample 1 || 1.27 || 1.26 || 1.27 || 1.30 || 1.35 || 1.29 || 0.04 ||
 * Sample 2 || 1.23 || 1.26 || 1.30 || 1.32 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.33 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.29 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">0.05 ||
 * <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">Sample 3 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.33 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.26 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.30 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.30 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.32 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.30 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">0.03 ||
 * <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">Sample 4 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.23 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.36 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.32 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.30 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.33 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.31 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">0.07 ||
 * <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">Sample 5 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.27 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.29 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.30 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.34 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.30 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.30 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">0.03 ||
 * <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">Sample 6 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.23 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.29 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.32 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.28 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.35 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.29 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">0.06 ||
 * <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">Sample 7 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.33 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.36 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.32 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.30 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.29 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.32 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">0.04 ||
 * <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">Sample 8 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.44 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.36 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.32 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.36 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.27 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.35 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">0.09 ||

Table 3 (Refractive index vs Phosphate Level):
 * || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">PO4 Level || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">Refractive Index ||
 * <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">Sample 6 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">0 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.29 ||
 * <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">Sample 5 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">0 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.30 ||
 * <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">Sample 4 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">0 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.31 ||
 * <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">Sample 3 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.33 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.30 ||
 * <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">Sample 2 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">2.66 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.29 ||
 * <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">Sample 7 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">2.66 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.32 ||
 * <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">Sample 1 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">3.33 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.29 ||
 * <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">Sample 8 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">3.66 || <span style="display: block; font-family: Arial,Helvetica,sans-serif; text-align: center;">1.35 ||

Graph 1:

Conclusion:

According to Graph 1, the refractive index of each sample of water from Tay Ho Lake is independant of the phosphate level in each sample. Also, the data points are inconclusive because their uncertainty range all share the normal refractive index of water, which is 1.33.

Some limitations in this lab were that the samples were collected only around the sidewalk, that the samples were only within 1m from each other, and that the samples were collected only from the surface of the lake.