In science class, Blaine’s teacher puts one glow stick in a cup of hot water and another glow stick in a cup of cold water. She asks the students to think about how the temperature of the water will affect the chemical reaction that occurs inside the glow stick once it is bent and starts to glow.
The temperature of the water can affect the chemical reaction inside the glow stick in a few ways:
1. Rate of Reaction: Generally, higher temperatures increase the rate of chemical reactions. This means that the glow stick in hot water might produce light more quickly or more intensely compared to the one in cold water.
2. Brightness: Higher temperatures can increase the brightness of the glow stick. When the reaction inside the glow stick is faster, more light is produced, resulting in a brighter glow. Therefore, the glow stick in hot water may appear brighter than the one in cold water.
3. Duration: Temperature can also affect the duration or duration of light production. Higher temperatures may cause the chemical reaction inside the glow stick to occur more rapidly, but it may exhaust the chemicals faster as well, causing the glow stick to stop glowing sooner than the one in cold water.
Overall, the glow stick in hot water may produce more intense light, but it may not last as long as the one in cold water due to the differences in chemical reactions caused by temperature.
The temperature of the water can indeed affect the chemical reaction that occurs inside the glow stick. Here are the step-by-step explanations:
1. Activation of the Reaction: When a glow stick is bent, a glass ampule inside it breaks, causing two chemicals to mix together. The most common chemicals used in glow sticks are hydrogen peroxide (H2O2) and a phenyl oxalate ester (such as bis(2,4,6-trichlorophenyl)oxalate or TCPO), along with a fluorescent dye.
2. Energy Transfer: The breaking of the glass ampule releases potential energy, which is then transferred to the chemicals. This energy is needed to initiate the chemical reaction. The higher the temperature of the water, the more energy is available to transfer to the chemicals inside the glow stick.
3. Speed of Molecules: Temperature is a measure of the average kinetic energy of molecules in a substance. As the temperature increases, the kinetic energy of the molecules also increases. In hot water, the kinetic energy of the water molecules is higher compared to cold water. Consequently, the molecules in the hot water move faster and collide more frequently.
4. Collision Rate: Increased molecular motion and collision rate in hot water lead to a higher chance of collisions between the chemicals inside the glow stick. This increases the likelihood of the chemicals coming into contact with each other more frequently and quickly, facilitating the chemical reaction.
5. Reaction Rate: The reaction between hydrogen peroxide and TCPO is an exothermic reaction, meaning it releases energy in the form of heat and light. As the reaction rate increases due to higher collision rates in hot water, more energy is released, resulting in a brighter and more intense glow.
In summary, the higher temperature of the water can increase the kinetic energy of the water molecules, leading to faster and more frequent collisions between the chemicals in the glow stick. This ultimately results in a faster and brighter chemical reaction, causing the glow stick to glow more intensely.
To understand how the temperature affects the chemical reaction in a glow stick, we need to explore the underlying chemistry.
Glow sticks contain two main components: a plastic tube and an inner glass vial. Inside the glass vial, there are two substances: a dye and a chemical called a "fluorophore." The plastic tube contains hydrogen peroxide, and there's a small glass vial of a different chemical, called a "catalyst," inside the plastic tube as well.
When you bend a glow stick, it breaks the glass vial inside, allowing the chemicals to mix. The hydrogen peroxide reacts with the catalyst, causing a chemical reaction that produces light. The dye adds color to the light, creating the glowing effect.
Now, let's consider the effect of temperature on this chemical reaction:
1. Hot water: When a glow stick is placed in hot water, the molecules in the reactants (hydrogen peroxide, catalyst, and dye) move faster due to increased thermal energy. This increase in energy can speed up the chemical reaction, causing the glow stick to glow more brightly and for a shorter duration. The reaction happens faster because the molecules collide more frequently, leading to more efficient mixing and increased light production.
2. Cold water: Conversely, when a glow stick is placed in cold water, the molecules in the reactants move slower due to decreased thermal energy. This decrease in energy can slow down the chemical reaction, resulting in a dimmer and longer-lasting glow. The reaction occurs slower because the molecules collide less frequently, leading to less efficient mixing and reduced light production.
In summary, the temperature of the water affects the chemical reaction in a glow stick by influencing the speed of the reaction. Hot water speeds up the reaction, resulting in a brighter but shorter-lasting glow, while cold water slows down the reaction, leading to a dimmer but longer-lasting glow.