1. For this science fair project, the independent variable is the method of removing the dust mites –  sun drying, hot wash followed by sun drying, hot wash followed by dryer cycles, cold wash followed by sun drying or cold wash followed by dryer cycles. The dependent variable is the number of dust mites remaining on the pillow case. This is determined by observing the pillow case under the magnifying glass and counting the number of dust mites. The constants (control variables) are the size of the marked area, the type of pillow case cloth, the hot water temperatures and the cold water temperatures.

2. Five pillow cases which are known to be infected with dust mites are chosen for this science fair project. The material for all 5 pillow case must be the same.

3. Using the ruler and marker pen, a 5cm by 5cm area is marked on the pillow case. By observing with a magnifying glass, the number of dust mites found in the area is counted for each of the 5 pillow cases and recorded in the table given below.

4. The 5 pillow case are then subjected to the following conditions:

a. Pillow case 1 – hang and dry under a hot afternoon sun for 2 hours

b. Pillow case 2 - wash in hot water at 60 °C and dry in the hot sun for 2 hours

c. Pillow case 3 - wash in hot water  at 60 °C and dry in a dryer for 2 hours

d. Pillow case 4 - wash in cold water at 0 °C and dry in the hot sun for 2 hours

e. Pillow case 5 - wash in cold water at 0 °C and dry in a dryer for 2 hours

5. The 4 pillow cases that are to be washed are placed in the washing machine separately to prevent cross contamination. After drying, the pillow cases are inspected under the magnifying glass once again and the number of dust mites are counted and recorded in the table below.