Heat is a form of energy, while temperature is a measure of the average kinetic energy of the molecules present in a system. Since both systems are measure to be at , their average kinetic energies are the same. The cup and the bathtub have the same temperature; however, since the bathtub contains more water, it contains more molecules. Temperature is the measure of heat energy per molecule. A greater number of molecules at the same temperature is indicative of more heat energy than fewer molecules at that temperature. Since the bathtub has more molecules, it has more heat energy even though the two systems have the same temperature.

A temperature gradient is always needed for heat transfer to occur. The temperature difference is what drives a flow of heat, as heat will always travel from an area of higher temperature to an area of lower temperature. This can occur between two materials, or within a single material. For example, if an iron pot is placed on a stovetop, the entire metal pot will become hot even though only the bottom is in contact with the heat source. This is because the heat transfers through the metal, from the high heat at the bottom to the lower heat at the top.

Enthalpy, or , is the total energy of a thermodynamic system. Similar to how mechanical energy can change during mechanical processes, involving changing distances of velocities, enthalpy will increase or decrease with changes made to the thermodynamic state of the system. It is simply a measure for a different form of energy.

When an object is changing forms (solid to liquid in this case), the temperature remains constant. All of the energy that would normally go towards changing the internal temperature of the object is going into  the latent heat of fusion or enthalpy of fusion instead.

Entropy is the measurement of disorder within a system, or how far it is from thermal equilibrium. Remember that everything in nature tends towards an equilibrium. The further from that equilibrium something is, the more "disordered" it is when compared to nature's preferred state.

When two waves are superimposed, the interference can either be constructive or destructive. In this case, the interference is constructive and the waves are in phase, which means we add the amplitudes together.

Since each wave has an amplitude of , our new amplitude will be .

When two waves are superimposed, the interference can be either constructive or destructive. In this case the interference is destructive, which means our resultant amplitude will be the difference of the two given amplitudes.

That means our new amplitude will be .

When two waves are superimposed with destructive interference, they cancel each other out. Since these two waves are identical, they will completely cancel each other out and there will be no wave. It will be still.

Radio waves have the smallest frequency and longest wavelength. This is why they are not dangerous. Microwaves have the next longest wavelength and are what are used to warm up cold foods. Infrared waves are the next longest wavelength and border the red light on the visible spectrum. Infrared waves are used in remote controls and night vision. Visible light is next and is what we can see with our eyes. Next is ultraviolet, which borders the violet light on the visible spectrum. These are the damaging rays by the sun and are essentially “super-violet” rays. Next is X-rays. These have very high frequencies and are dangerous in high quantities. Gamma rays are the shortest wavelength and the highest frequency and the most dangerous. These cosmic rays often come from stars and other celestial objects.

When waves interfere with one another, they pass through each, and others can undergo either constructive or destructive interference.  In constructive interference, waves add together to produce a briefly more massive wave.  In destructive interference, waves subtract from each other to create a smaller wave.  However, once the waves move past one another, they will return to their original shape and size.