The weight of an object changes when you go to the moon because the gravitational force exerted by the moon is different from that of the Earth. The force of gravity is directly proportional to the mass of the object and inversely proportional to the square of the distance between the centers of the objects. Since the moon has a smaller mass than the Earth, the gravitational force it exerts is weaker.

To calculate the weight of an object on the moon, we can use the following formula:

```

Weight on moon = (Mass of object) × (Gravitational acceleration on moon)

```

The gravitational acceleration on the moon is approximately 1.62 m/s², which is about one-sixth of the gravitational acceleration on Earth. This means that an object on the moon will weigh about one-sixth of its weight on Earth.

For example, if an object weighs 60 kg on Earth, it will weigh only 10 kg on the moon. This is why astronauts and spacecraft appear to "float" when they are on the moon.

It's important to note that the weight of an object is not the same as its mass. Mass is a measure of the amount of matter in an object, while weight is a measure of the force of gravity acting on that object. An object's mass remains the same regardless of its location, but its weight can change depending on the gravitational field it is in.