1.)When testing a patient’s eyes for focusing ability, one doctor uses these three cards. Card 1 is placed 3.0 m from the patient. The other two cards are placed so that the letter E on them will appear to be the same size to the patient as the E on Card 1.
a.)Measure the width of the E on each card.
b.)Calculate the ratios:
width on card 1/width on card 2 and width on card 1/width on card 3.
c.)Use these ratios to predict how far Card 2 and Card 3 should be placed from the patient, if the patient’s vision is normal.
d.)Create the three cards and carry out the test with a partner. Do the results confirm your predictions?
e.)Can you describe how the experiment would change if Card 2 was placed 3 m away to start?
I will happy to criquue your work, but am not holding my breath waiting for that to happen.
a.) To measure the width of the E on each card, you will need a ruler or any measuring tool with millimeter markings. Place the card on a flat surface and align the ruler with the width of the letter E. Carefully measure the distance from one end of the E to the other, making sure to note the measurement in millimeters.
b.) To calculate the ratios, divide the width on Card 1 by the width on Card 2, and then divide the width on Card 1 by the width on Card 3. For example, if the width of the E on Card 1 is 30 mm, and the width of the E on Card 2 is 10 mm, the ratio would be 30/10 = 3. Repeat the same process for Card 1 and Card 3.
c.) To predict how far Card 2 and Card 3 should be placed from the patient, use the ratios calculated in the previous step. If the patient's vision is normal, the ratios should remain the same. For example, if the ratio between Card 1 and Card 2 is 3, and the width of the E on Card 1 is 30 mm, then the width of the E on Card 2 should be 10 mm. Based on this ratio, you can calculate the theoretical distance for Card 2 by multiplying the width on Card 2 by the ratio and placing it at that distance from the patient. Repeat the same process for Card 3.
d.) Create three cards with the letter E of varying widths as measured. Place Card 1 at a distance of 3.0 m from the patient, according to the instructions. Then, based on the predicted ratios, place Cards 2 and 3 at the calculated distances from the patient, making sure the E on each card appears to be the same size to the patient as the E on Card 1. Perform the test with a partner by having the partner view and compare the sizes of the E on each card.
Observe if the results confirm the predictions made based on the ratios. If the E on Card 2 and Card 3 appears to be the same size as the E on Card 1 to the partner with normal vision, then it confirms the predictions.
e.) If Card 2 was placed 3 m away to start, it would change the experiment because the original ratio between Card 1 and Card 2 would no longer be valid. To adapt the experiment, you would need to recalculate the ratios using the actual measurements of the E on Card 2 and Card 3 at the new positioning. The distances for Card 1, Card 2, and Card 3 would then be adjusted based on the recalculated ratios.