if a 9.8 object is above a glass held up by a spring lift then why does it weigh 7.8 when in the water?

Question

and say there is a line drawn where the water was before, why afterwards is the water higher? bernoulli's principle??

Answer 1

Bouyancy. The 9.8 (you did not specify the units) object, when in water, is partially supported by the bouyant force. The bouyancy force is the weight of the displaced water. The water level is higher because the displaced water had nowhere else to go but up. The volume of water is still the same though.

Answer 2

An object will have a certain weight in air. When weighted in water it will be less because the water molecules push up against it. As the object enters the water, it increases the volume of the water, so the water volume goes up - it's the two volumes of the water and the volume of the object in the water. The weight of the increased volume of water will be equal to the weight (mass) of the difference of the object before and after it went into the water.