If the motion of particles is decreasing, is heat flowing into or out of the substance? also, explain why

If particle motion is slowing, the particles are losing energy, which means that heat is flowing out of the substance. This also means that it is transferring its energy to another substance which has less energy than the first object. Heat is directly correlated to energy, which is related to the particles' movement. If the particles are slowing, heat is leaving the object.

Adding energy (heating) atoms and molecules increases their motion, resulting in an increase in temperature. Removing energy (cooling) atoms and molecules decreases their motion, resulting in a decrease in temperature. Energy can be added or removed from a substance through a process called conduction. In conduction, faster-moving molecules contact slower-moving molecules and transfer energy to them. During conduction the slower-moving molecules speed up and the faster-moving molecules slow down. Temperature is a measure of the average kinetic energy of the atoms or molecules of a substance. Heat is the transfer of energy from a substance at a higher temperature to a substance at a lower temperature. Some materials are better conductors of heat than others.