Final answer:
The measurement on a scale is indeed affected by Earth's gravitational field. This is why weight, as measured on a scale, varies depending on the strength of the local gravitational force, being different on Earth compared to the moon.
Step-by-step explanation:
The statement that the measurement on a scale when you stand on it is affected by the gravitational field on Earth's surface is true. Scales measure the force of gravity acting on the mass of an object, which is why we use the term 'weight'. The weight of an object on Earth is the product of its mass and the acceleration due to gravity (approximately 9.80 m/s²). Hence, the reading of a scale represents this weight.
If the same person were to stand on a scale on the moon, their weight would be less due to the moon's weaker gravitational field. Similarly, if you perform a balance scale experiment on Earth with a book and a 1-kg weight, it will balance; however, if you take this setup to the moon, it will still balance, but the actual force (weight) acting on each side will be lesser because the moon's gravitational acceleration is about one-sixth of Earth's.
In summary, a balance scale compensates for variations in gravity by maintaining the same relative mass on both sides, while a bathroom scale that measures force would show different values on Earth than on the moon because the gravitational force would be different.