Gravitational Field Strength,g
Defined as the gravitational force acting per unit mass on an object.

On Earth the gravitational feild strength is about 10N/kg

1kg of mass experiences a force of 10N due to Earth's gravitational pull.

gravitational field strength is equivalent to acceleration of free fall

Question:why would your weight decrease if you are on the moon
Answer:because moon has a lower gravitational field strength.Infact,you would be 1/6 of your's Earth weight on the moon