Marty runs the fan for exactly one minute in front of each sand pile. He sets the fan to low speed for the first pile, medium speed for the second pile, and high speed for the third pile. Then he records the new height of each sand pile.

Question

The results of Marty's experiment are shown in the table below. Which fan speed caused the most sand erosion?
Fan Speed Sand Pile Starting Height Final Height
low first 25 cm 23 cm
medium second 25 cm 20 cm
high third 25 cm 16 cm

Answer 1

To determine which fan speed caused the most sand erosion, we can calculate the amount of erosion for each sand pile by subtracting the final height from the starting height.

1. Low Speed (first pile):

   • Starting Height: 25 cm
   • Final Height: 23 cm
   • Erosion: \(25 , \text{cm} - 23 , \text{cm} = 2 , \text{cm}\)

2. Medium Speed (second pile):

   • Starting Height: 25 cm
   • Final Height: 20 cm
   • Erosion: \(25 , \text{cm} - 20 , \text{cm} = 5 , \text{cm}\)

3. High Speed (third pile):

   • Starting Height: 25 cm
   • Final Height: 16 cm
   • Erosion: \(25 , \text{cm} - 16 , \text{cm} = 9 , \text{cm}\)

Now, we compare the erosion amounts:

• Low Speed: 2 cm
• Medium Speed: 5 cm
• High Speed: 9 cm

The fan speed that caused the most sand erosion is the high speed, which resulted in 9 cm of erosion.