To learn more about chemical reactions and engineering design, the 7th graders made portable egg incubators.
The students were asked to imagine they volunteered to rescue reptiles that are living in the path of new construction. Having supposedly talked to the construction workers and a nearby reptile conservation center, the students' role was to design a reptile egg incubation device to keep the eggs warm and properly positioned during transportation to the conservation center.
In order to know what type of incubator to create, the students had to use a reptile egg identification chart. By looking at the picture of the eggs, the students took note of the location, shape, and length to match their reptile and incubation temperature.
The first investigative question asked if the calcium chloride dissolved in water affects the temperature change. To figure this out, the 7th graders took the temperature of two water cups. Then, they added 1/4 tsp of calcium chloride to one cup and 1/2 tsp to the other and took the temperature.
After recording the final temperature, they added 1/t tsp of baking soda to the solution that reached the highest temperature. Then, they recorded the lowest final temperature reached.
By doing this experiment, the students identified how baking soda affects the temperature of a calcium chloride solution and if they should use it in the design of their portable reptile egg incubator.
The second investigative question asked the students to figure out how much calcium chloride, baking soda, and water should be mixed to reach the right temperature range to incubate snake eggs.
This experiment asked students to mix 1/2 tsp of calcium chloride and 1/8 tsp of baking soda with water and to record the temperature. Next, they had to adjust the amount of calcium chloride or baking soda and try the reaction two more times to achieve the target temperature.
Now that the students had found out how to make the ideal temperature, they had to determine if enough heat transfers through a plastic bag to reach the right temperature range. The students did this by pouring their calcium chloride and baking soda mixture into one corner of the plastic bag and 15 milliliters of water into the other, so they do not touch. After squeezing out the air, the students started the chemical reactions and recorded the temperature with a thermometer.
This chemical reaction project was no easy feat. It required the 7th graders to make precise measurements and take their time when conducting the multiple trials. By doing these experiments, the students practiced their knowledge learned in class to place themselves in a real-life scenario. Now, the 7th graders know how to make an egg incubator for a specific reptile by conducting chemical reactions.