# How can both kinetic and potential energy increase simultaneously in a open substance?

I have an open test tube containing a solid substance. In a school environment, we heat it, which increases thermal (kinetic) energy, and this heat breaks its bonds, increasing its potential energy, turning it into a liquid. I understand in thermodynamics, there is a conversation of energy, yet since this test tube is open to other factors, such as air, can this occur?

Also, if this experiment were insulated what would occur?

• First off, you are ADDING energy. What If I grab a ball and throw it up in the air? – Joseph Hirsch Dec 11 '16 at 23:16
• I edited my question, do you think you can help with that? thanks – user38672 Dec 11 '16 at 23:33
• Need a more complete description. How would you heat it if it's insulated? – Joseph Hirsch Dec 11 '16 at 23:40
• Sorry, it is heated due to dropping another substance inside of it. So we have a liquid, if we drop a substance inside (which heats and solidifies it) and quickly covered it/ blocked it from air, what would occur? – user38672 Dec 12 '16 at 2:05
• The energy is being redistributed. It is not being created.The heat that you are using to increase the energy of your test tube has to come from somewhere (e.g. burning fuel). Conservation of energy holds true in all scenarios. If conservation of energy is not satisfied, you are probably leaving out something. – CoffeeIsLife Dec 12 '16 at 6:25

The kinetic and potential energy of the sample has increased. Kinetic energy in translational motion of the molecules and internal potential and kinetic energy of the molecules has also increased as they have absorbed some of the heat as vibrational and rotational energy. (A non-linear molecule with N atoms has $3N-6$ different ways of vibrating, e.g ethane has 18 ways).