Cold Pack Investigation
People use self-warming and self-cooling devices for many purposes such as keeping drinks cold or food warm. Medical professionals also use these types of devices to store medicines and other substances that need to stay colder than room temperature. These cooling and warming devices use a chemical reaction to produce their chilling and warming effects. Compounds combine in endothermic (heat absorbing) or exothermic (heat releasing) reactions within these devices to help them keep items cool or warm.
Jacob and Natalie are asked by their science teacher to design a warming or cooling device. They decide to design a cold pack that can be used to help keep food cool. Jacob and Natalie read about different substances that can be used inside cold packs and learn that most cold packs use endothermic reactions to cool objects. They find the table below while researching.
The table titled 'Effect on Temperature of Different Substances' shows Sample, Composition, Initial temperature in degrees Celsius and Final temperature in degrees Celsius. Sample 1's composition is Ammonium nitrate, urea and water, Initial temperature is 22.0, and final temperature is negative 17.5. Sample 2's composition is Ammonium nitrate and water, Initial temperature is 22.0, and final temperature is negative 4.0. Sample 3's composition is Urea and water, Initial temperature is 22.0, and final temperature is 4.0. Sample 4's composition is Water, initial temperature is 22.0, and final temperature is 22.0
Inline Dropdown Question
Jacob and Natalie first make a cold pack by mixing several substances in a thick, plastic bag (they call this Design 1). Jacob and Natalie decide they need to modify Design 1. They make Design 2 shown in the drawing below. The outer bag has an inner bag inside of it. The inner bag contains a substance that is released and allowed to mix with the substance in the outer bag only after being popped open by a person.
The drawing labeled 'design 2' shows an outer bag that contains a substance and an inner bag. The inner bag also contains a substance.
Use the drop-down menus below to complete the statement explaining the difference between Design 1 and Design 2.
Design 2 will allow the cold pack to Query 1
heat energy only when it is needed to cool food. Design 1 Query 2
heat energy from the moment it is made. This means that Design 1 will likely feel Query 3
when it is needed than Design 2 since the timing of the chemical reaction Query 4
.
1 answer
Sure! Here is how you can complete the statements based on the provided context:
Design 2 will allow the cold pack to absorb heat energy only when it is needed to cool food. Design 1 absorbs heat energy from the moment it is made. This means that Design 1 will likely feel cooler when it is needed than Design 2 since the timing of the chemical reaction is activated immediately.
So the completed statements are:
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