Prototype testing proceedure
Thermos Challenge
Experiment procedure
Purpose :
- To create and test a thermos that will contain heat for 30 minutes with minimal heat loss. The purpose of the test is to find any inconsistences with the prototype thermos such that any improvements can be applied to subsequent models.
Materials :
- For the experiment, you will need
- 150ml of water that will be brought to 100 degrees C
- A hot plate that can reach 100 degrees C
- A small 200ml glass beaker
- A thermometer, or any other way of test the water heat
- One set of prongs with rubber forks to hold the hot beaker
Safety Precautions :
- For safety purposes, use the prongs to take the hot beaker from the hot plate.
- Poor the boiling water into the thermos in pairs of two people. (One holding the thermos and one holding the beaker with the prong to avoid burning or spilling water.)
- Put the beaker onto a brick when your water has to transferred to the beaker to ensure safe cooling of the beaker in order to prevent shattering.
- Turn the hot plate off and unplug at the end of the experiment.
Procedure :
- Take the glass 200ml beaker and fill it to 150ml with water at room temperature.
- Turn the hot plate on and set it to 100 degrees C.
- Place the beaker with the water onto the hot plate
- Measure the temperature until the water reaches a boil at 100 degrees C
- Prepare the thermos
- Use the prong to remove the beaker from the hot plate and immediately poor the water into the thermos with the help of a friend.
- Measure the heat of the water as soon as it has been placed into the thermos. The other partner should turn the hot plate off and unplug it as this time.
- The heat test will be conducted for 30 minutes.
- Test the temperature at the end of the 30 minutes.
- When the 30 minutes is up, poor the hot water into a sink and clean up the area.
Data
Create a table of values for time at the beginning and the temperature at the beginning. Have a section for the time and temperature at the end.
Prototype #1 Prototype #2
Materials and Thermal conductivity :
#1 Total cost $2.65
Cardboard milk container – 0.05 W/m.K – $0.50
Black paint – radiation – $0.25
Tape 15 inches – 0.08 W/m.K – $0.75
Aluminum foil 12 inches squared – 250 W/m.K – $0.3
Styrofoam cup – 0.03 W/m.K – $0.85
#2 Total cost $5.05
Glass bottle – 0.0025 W/m.K – $1.00
Almuminium foil 72 square inches – 250 W/m.K – $3.60
Tape 9 inches – 0.08 W/m.K – $0.45
Results :
#1
We started the test with 95 degree C water and ended the test with this prototype with 60 degree C water. The thermos was falling appart because the tape was falling off due to the water vapour. The aluminium lid that we made was also begining to fold in due to the heat which was making the particle expand in the aluminium foil. The lid was letting heat out because of this, and because it was not air tight. A good thing we found was with the cardboard. We found that the cardboard was a really good heat insulator and did not allow the heat to transfer outside. It was good as an outer layer.
#2
The water that was initially in the thermos at the beginning of the experiement was 95 degrees C. At the end of the experiement, it was 65 degrees C. We found that this prototype did not have any technical difficulties as oppose to the first prototype which began to fall apart. We found that the aluminium was great at keeping the heat inside. It was a great insulator to have on the outer layer to make sure any heat that was transfered throught the glass, was was kept inside the thermos by transfering to the aluminium. The cap allowed the thermos to be air tight which enabled us to keep most of the heat inside the thermos instead of escaping through vents.
#1
Pros : The cardboard was a great insulator to trap the heat inside the thermos. The thermos had a low cost which enables us to use extra parts like paint which radiated the heat throughout the thermos which aided in the heat retension.
#2
Pros : The lid was air tight which kept the heat from escaping through cold air. The glass was a great insulator because it was a solid that kept the heat energy moving quickly in between the molecules of the glass which made the glass warm and kept the water hot.
#1
Cons : The thermos was falling appart because of the water vapour. The tape was not sticking due to the molecules of hot water which were rising and getting through the cuts in the cardboard container. The aluminium lid was also getting a lot of heat transfered into it which was being cooled down by the air and in turn cooled the thermos instead of keeping it warm.
#2
Cons : It was really over priced and was not able to preform to the extent that we would have hope despite the price. The container was too big. The amount of water contained was not optimal for the size of the thermos. 150mL of water was not enough to keep hot enough in the 500mL glass thermos.
#1
Improvements to make : The main thing we wanted to improve for our next prototype was to create a designe that enabled us to seal the thermos shut instead of having little air vents for heat to escape. We believed this to be the best improvement to make to insure that the most amount of heat was conserved.
#2
Improvements we made : We took the idea of making the thermos air tight and applied that to the prototype number 2. In using a glass container, we eliminated the possibility of our thermos falling appart due to water vapour rising, entering the materials and making them soggy.
Improvement we wanted to make : We were looking into ways to create a thermos that was able to heat itself using wiring and electricity. We wanted a thermos that was relatively air tight, had a small design, and that would get us the best heat retention possible.
Final prototype/product
Total cost $3.4
Paper cup – 0.05 W/m.K – $0.55
Aluminium can no lid- 250 W/m.K – $0.65
Foam insulator – 20 square inches – 0.03 W/m.K – $1.00
Wires – $1.00
Electrical tape – 4 inches – $0.20
Results : The results of this experiment where not as we expected. For the first half of the experiment, the electric wire was heating up the aluminium can which was transfering the heat into the water, further heating it past the expected heat. For the second half of the experiment, we could not use the wiring and the electricity. This heavily impacted our design and made is lose heat fast. The foam insulation and the aluminium can alone where not enough the keep the heat from transfering out of the water. The heat was not able to stay in the water. Everything else worked as expected, the thermos was in one piece and there was no deterioration in the thermos itself. We began the experiment at roughly 94 degrees C and ended the experiment with 45 degrees C.
Why : The electric wiring was working well with the thermos and it was heating the water. The electrons moving through the wires transfered into the aluminium can where they began to move quickly and bounce off of the molecules in the aluminium which heated it up and caused the heat to transfer to the water which was inside the can. The foam insulation was another layer that added the conservation of the heat energy because it had little air bubbles within the insulator which trapped the heat and did not let it transfer. The paper cup on top made for a good lid because it was sealed when squeezed on to the foam insulator. The paper was a good insulator of heat which allowed the heat energy to stay within and not dissipate. We knew that if we picked good enough insulators for our thermos, we could trap the heat energy from the water. We wanted materials that would retain the heat since we knew that energy could not be lost unless there was an external source cooling the water. Hence why we used the foam insulator as an outer layer to contain the water. We also learned that the water vapour was rising and then cooling at the top then falling back in, so we wanted a way to reheat the water after the process of condensation.
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