Question

marcy uses ph strips to measure the ph of water samples from several ponds in the city park. which reason explains why using a ph meter would improve the accuracy of her data?

• the ph meter gives a digital readout.
• the ph meter uses numbers instead of colors.
• the ph meter can distinguish between smaller differences in ph than ph strips can.
• the ph strips are more expensive to use.

Explanation:

Analyze the measurement tools

pH strips rely on visual color matching, which is subjective and typically limited to whole or half-unit increments. A pH meter uses an electrode to measure the electrical potential difference, providing precise numerical values.

Evaluate accuracy and precision

Accuracy in scientific data is improved when a tool can detect smaller, more precise differences in a value. A pH meter can measure pH to one or two decimal places (e.g., 7.24), whereas pH strips can generally only distinguish broader ranges (e.g., 7 vs 8).

Assess the given options

• "The pH meter gives a digital readout" describes a feature, not why accuracy is improved.
• "The pH meter uses numbers instead of colors" describes the format, not the underlying measurement capability.
• "The pH meter can distinguish between smaller differences in pH than pH strips can" directly explains how the tool increases precision and accuracy.
• "The pH strips are more expensive to use" is factually incorrect and relates to cost, not data accuracy.

Answer:

• The pH meter gives a digital readout.
• The pH meter uses numbers instead of colors.
• The pH meter can distinguish between smaller differences in pH than pH strips can. (Correct answer)
• The pH strips are more expensive to use.