I believe it is called the Greenhouse effect.
Explanation:
Given that,
Mass of the object, m = 7.11 kg
Spring constant of the spring, k = 61.6 N/m
Speed of the observer, 
We need to find the time period of oscillation observed by the observed. The time period of oscillation is given by :

Time period of oscillation measured by the observer is :

So, the time period of oscillation measured by the observer is 5.79 seconds.
Gas because liquids and solids volumes don't change from switching containers.
Answer:
1. Battery
2. Copper wire
3. Nail or piece of metal (zinc, iron, or steel).