Accurate Measurement

Question 1

Sam wants to find the mass of a small rock. He uses a digital scale that shows grams and records three measurements: 45.2 g, 45.4 g, and 45.3 g. Which statement best explains why Sam took at least three readings?

Accepted Answer

Taking several readings lets him calculate an average, which reduces the impact of any one inaccurate measurement.

Answer

Using three readings makes the experiment take less time.

Answer

Recording three measurements proves the scale is working perfectly.

Answer

Measuring three times changes the rock’s mass to get a more accurate value.

Question 2

A scientist uses a thermometer to find the temperature of a water sample. She records three separate readings and then calculates the average temperature. Which statement best explains why she takes at least three repeat readings?

Accepted Answer

It reduces the effect of random errors, giving a more reliable result.

Answer

It makes the temperature higher.

Answer

It allows you to use the highest reading.

Answer

It ensures the thermometer is calibrated.

Question 3

Sam uses a thermometer to measure the temperature of a beaker of water. He records three readings: 24°C, 25°C, and 24°C. Which statement best explains why Sam took three readings?

Accepted Answer

Taking several readings helps to ensure the result is reliable by reducing the impact of any one inaccurate measurement.

Answer

Multiple readings allow Sam to pick the highest temperature, which is the most accurate.

Answer

Repeating the measurement makes the temperature increase, giving a more precise result.

Answer

The first reading is always the most accurate, so the other readings are unnecessary.

Try three questions

Sam wants to find the mass of a small rock. He uses a digital scale that shows grams and records three measurements: 45.2 g, 45.4 g, and 45.3 g. Which statement best explains why Sam took at least three readings?

A scientist uses a thermometer to find the temperature of a water sample. She records three separate readings and then calculates the average temperature. Which statement best explains why she takes at least three repeat readings?

Sam uses a thermometer to measure the temperature of a beaker of water. He records three readings: 24°C, 25°C, and 24°C. Which statement best explains why Sam took three readings?

Keep going on this shelf