Objective: To visualize the intangible concept of energy (First and Second Laws of Thermodynamics) using a concrete process, a relay race using sand.
1st Law of Thermodynamics: Often called the Law of Conservation of Energy. This Law states that energy cannot be created or destroyed, it just changes forms as it is transferred from one level to another. Thus, the total amount of energy available in any system is constant.
2nd Law of Thermodynamics: As energy changes form, it moves from more useful forms to less useful forms. It gets degraded as it moves from a higher energy state to a lower energy state (usually heat). Energy flows in one irreversible direction. It cannot be recycled or reused.
This law also predicts entropy. Entropy is the measure of disorder in a system. Because heat is lost when energy is transferred, entropy always increases with time. Eventually, because of the 2nd Law of Thermodynamics, energy in the Universe is becoming less useful over time.
In this activity, you will run a relay race.
· Divide into two groups, and line up facing each other. Spread out slightly more than arm’s length apart.
· Groups should be sorted from the tallest to the shortest. The tallest person likely has the largest hands, and the shortest the smallest.
· Each group represents a “food chain.”
· The person with the biggest hands (can hold the most energy) goes first. The person with the smallest hands goes last.
1. Record the original volume of the sand in the beaker in Table 1.
2. One person in each group will be the timer. Set a stopwatch to zero.
3. Start time, and the Timer will pour the entire beaker of sand onto the hands of the First Person. First Person moves as fast as possible to pass the sand to the Next Person in line, all the way to the Last Person. Try to beat the row across from you! Best time wins!
4. Last Person holds onto the sand. Pour it back in the beaker and bring it inside. We will measure and record the new volume in Table 1. Timer records end time in Table 2.
