Topic #3

 All particles of matter are ridiculously small  Imagine a drop of water on your fingertip- How many water particles do you think make up that water drop????  Would you believe about  Only about one thousand seven hundred million million million  This is why you can’t see them with your eye

 The particle model of matter is a scientific description of features of these tiny particles  1) all substances are made of tiny particles- too small to be seen  2) the particles are always in motion – vibrating, rotating and (in gases and liquids) moving around from place to place  3) the particles have spaces between them

 If the motion of the particles in a substance change, the temperature of the substance also changes  When a substance warms – the particles move faster  When a substance cools – the particles move more slowly So, temp up=motion up and vice versa

 Temperature indicates the average speed of particle motion in a substance!!!  Some particles in a substance move faster than average and some move slower  Obviously, this theory cannot be easily tested as the particles are too small to observe

 Antoine Lavoisier ( ) believed that an invisible substance called caloric fluid caused changes in temperature.  Anything that was hot had more caloric fluid and hot things could transfer fluid from one substance to another  After trying to find and prove that caloric fluid existed, scientists gave up

 Energy is a measure of something’s ability to do work or cause changes  Whenever something happens, energy is being transferred from one thing to another  In fact, one of the Laws of Conservation of Energy basically states that energy cannot be created or destroyed, only transferred between matter or transformed (you will learn this in physics class in high school!!!)

 Hot-air balloons, ovens, hot tubs – are all designed to release and transfer thermal energy = energy associated with hot objects  Couple rules: 1) Changes happen when there is a difference in energy 2) Energy is always transferred in the same direction – from a high energy source to something with lower energy

 There is a connection between thermal energy and temperature  Heating anything increases the total energy of all its particles  However, the average energy of the particles (the temperature) may increase a little or a lot  Ex. You may heat the gym with a small heater, but that doesn’t mean temperature increases

 Energy is not a substance  It cannot be weighed  It does not take up space  Energy describes a quality or condition of an object that gives it the ability to move, do work, or cause changes