STEM Project Marley Miller Ms. Barrett - 2nd Grade Marley Miller Ms. Barrett - 2nd Grade

Scientific Experiment Question  What is the effect of the amount of rubbing alcohol on the consistency of a cold gel pack?  What is the effect of oxygen on the temperature of a heat pack?  What is the effect of the amount of rubbing alcohol on the consistency of a cold gel pack?  What is the effect of oxygen on the temperature of a heat pack?

Experiment Prediction  Cold gel pack prediction: We can make this using 2 zip-lock freezer bags, water, rubbing alcohol and food color. I think using less rubbing alcohol will create a gel-like substance because it does not freeze.  Heat pack prediction: We can make this using 2 zip-lock bags, vinegar, baking soda, pan and kitchen stove. I think removing oxygen will allow the heat pack to increase in temperature.

Procedure: Cold Gel Pack  For this experiment we conducted three tests using different rubbing alcohol measurements in the mixture.

 Step 1: Measure and combine water and rubbing alcohol.  Test bag cups of water and 1 cup of rubbing alcohol  Test bag cups of water and.5 cup rubbing alcohol  Test bag cups of water and.25 cup rubbing alcohol  Test bag cups of water and 1 cup of rubbing alcohol  Test bag cups of water and.5 cup rubbing alcohol  Test bag cups of water and.25 cup rubbing alcohol

 Step 2: We then added food coloring so we could tell them apart and poured liquid into the bag  Test bag 1 - orange  Step 2: We then added food coloring so we could tell them apart and poured liquid into the bag  Test bag 1 - orange

 Test bag 2 - blue Test bag 3 - green

 Step 3: We removed the excess air from each bag before sealing them.  Step 4: They were double bagged to prevent leaking and placed in the freezer overnight.  Step 3: We removed the excess air from each bag before sealing them.  Step 4: They were double bagged to prevent leaking and placed in the freezer overnight.

Procedure: Heat Pack For this experiment we used 4 cups of vinegar and 4 tablespoons of baking soda. Step 1: Pour the vinegar into a pan on the stove and slowly added the baking soda while stirring continuously. For this experiment we used 4 cups of vinegar and 4 tablespoons of baking soda. Step 1: Pour the vinegar into a pan on the stove and slowly added the baking soda while stirring continuously.

 Step 2: Once the baking soda was dissolved we turned the stove to medium.  Step 3: We let the mixture to simmer for 45 minutes. This process evaporates the excess water from the mixture.  Step 4: Once white crystals begin to form around the side of the pan we removed it from the stove. There is a small amount of light yellow colored liquid that remains in the pan.  Step 5: This liquid is then poured into one of the zip-lock bags and placed into the freezer for 10 minutes to cool.  Step 2: Once the baking soda was dissolved we turned the stove to medium.  Step 3: We let the mixture to simmer for 45 minutes. This process evaporates the excess water from the mixture.  Step 4: Once white crystals begin to form around the side of the pan we removed it from the stove. There is a small amount of light yellow colored liquid that remains in the pan.  Step 5: This liquid is then poured into one of the zip-lock bags and placed into the freezer for 10 minutes to cool.

 Step 6: Place a pinch of the remaining white crystals from the pan into the zip-lock bag of liquid. This causes a chemical reaction turning the liquid into a more solid-like state and an increase in temperature.

Observation: Cold Gel Pack  The following morning we removed the bags from the freezer.  Test bag 1 - The consistency of the orange bag had not gelled and contained too much liquid.  Test bag 2 - The consistency of the blue bag was an improvement, however it still contained liquid.  Test bag 3 - The consistency of green bag was a perfect gel-like substance SUCCESS!  The following morning we removed the bags from the freezer.  Test bag 1 - The consistency of the orange bag had not gelled and contained too much liquid.  Test bag 2 - The consistency of the blue bag was an improvement, however it still contained liquid.  Test bag 3 - The consistency of green bag was a perfect gel-like substance SUCCESS!

Observation: Heat Pack  For this experiment we conducted two tests. The first test, we did not remove the excess oxygen from the zip-lock bag before sealing it. For the second test, we removed the excess oxygen from the zip-lock bag before sealing it.  The first test bag did gradually change into a solid substance however it did not increase in temperature.  The second test bag did change into a solid substance and there was a very noticeable increase in temperature.  For this experiment we conducted two tests. The first test, we did not remove the excess oxygen from the zip-lock bag before sealing it. For the second test, we removed the excess oxygen from the zip-lock bag before sealing it.  The first test bag did gradually change into a solid substance however it did not increase in temperature.  The second test bag did change into a solid substance and there was a very noticeable increase in temperature.

Experiment Conclusion  What did you learn?  You can change the outcome of an experiment by altering the measurements of your ingredients.  How did you make sure it was a fair test?  The only thing changed in this experiment was the rubbing alcohol, everything else remained the same.  What else do you want to try in the future?  Next year, I’d like to do an engineering project and build a robot.  What did you learn?  You can change the outcome of an experiment by altering the measurements of your ingredients.  How did you make sure it was a fair test?  The only thing changed in this experiment was the rubbing alcohol, everything else remained the same.  What else do you want to try in the future?  Next year, I’d like to do an engineering project and build a robot.