Wave Properties

Transverse Wave

A wave vibrating at right angles to the direction of its propagation.

Standing Wave

A vibration of a system in which some particular points remain fixed while others between them vibrate with the maximum amplitude.

Pulse Wave

A pulse wave or pulse train is a kind of non-sinusoidal waveform that includes square waves and similarly periodic but asymmetrical waves

Periodic Wave

In mathematics, a periodic travelling wave is a periodic function of one-dimensional space that moves with constant speed.

Longitudonal Wave

A wave vibrating in the direction of propagation.

Destructive Interference

Destructive interference occurs when the maxima of two waves are 180 degrees out of phase: a positive displacement of one wave is cancelled exactly by a negative displacement of the other wave.

Constructive Interference

Constructive interference occurs when the maxima of two waves add together (the two waves are in phase), so that the amplitude of the resulting wave is equal to the sum of the individual amplitudes.

Thermos Project

The Goal: To create a thermos that holds 150mL of water at 100°C, maintains as much temperature as possible for 50 minutes, looks aesthetically pleasing, and costs $3 or less to make.

My Process

Testing:

1. I heated 150mL of water to 100°C using a hotplate.

2. I safely poured the water into the thermos using tongs.

3. I started a 50 minute timer and prepared a temperature probe.

4. I measured the final temperature with the probe after 50 minutes.

4. I measured the heat loss by comparing the final temperature to the initial temperature.

The Prototypes:

Thermos v1

Thermos v1 is a soup can with a threaded lip, that will eventually house a lid in following prototypes. Thermos v1 was a prototype that I expected to fail due to the lack of a lid and insulation, but I needed to do this test in order to compare how much the following prototypes improved.

Material Thermal Conductivity J/(kg-K) Amount Cost $
Aluminum (Canister) 921 1 0.15
Polylactic Acid (3 dimensionally printed threaded lip)
2137 52g 1.30
Total 1.45

Test Results

Thermos v1 started with water at a temperature of 90°C in it and ended with 47°C after only 20 minutes. This was a drop in 43°C/20 minutes or -2.15°C per minute. The main thing I noticed during this test was that lots of steam came out of the top and the outside of the thermos was also hot; signs of significant heat loss, which is what I expected. The next prototypes would be improved by adding a lid and insulation.

Thermos v2

Thermos v2 is a soup can with a threaded lip & lid, and insulating foam around the exterior. Thermos v2 was a prototype that I expected to do much better than Thermos v1 because of the added lid to stop convection, and the added insulation to stop conduction, but It still needed an outer chassis to prevent further conduction.

Material Thermal Conductivity J/(kg-K) Amount Cost $
Aluminum (Canister) 921 1 0.15
Polylactic Acid (3 dimensionally printed threaded lip)
2137 52g 1.30
Polylactic Acid (3 dimensionally printed threaded lid) 2137 52g 1.30
Polystyrene foam (outer insulation)
1131 6.5cm² 1.00
Total 3.75

Test Results

Thermos v2 started with water at a temperature of 99°C in it and ended with 50°C after 50 minutes. This was a drop in 49°C/50 minutes or -0.98°C per minute which is much better that Thermos v1. The main thing I noticed during this test was that some of the aluminum canister was still exposed and this let out enough heat that you could feel it. The last prototype would be improved by adding more insulation in the form of an outer chassis.

Thermos v3

Thermos v3 is a soup can with a threaded lip & lid, insulating foam, and an outer chassis. Thermos v3 was my third and final prototype, and I expected it to do much better than Thermos v2 because the added exterior chassis could help prevent heat loss due to conduction. Because I already went $0.75 over budget with the last prototype, I rationalized going even more over budget to add this exterior chassis to try to make it work as well as possible.

 

Material Thermal Conductivity J/(kg-K) Amount Cost $
Aluminum (Canister) 921 1 0.15
Polylactic Acid (3 dimensionally printed threaded lip)
2137 52g 1.30
Polylactic Acid (3 dimensionally printed threaded lid) 2137 52g 1.30
Polystyrene foam (outer insulation)
1131 6.5cm² 1.00
Polylactic Acid (3 dimensionally printed outer chassis) 2137 77g 1.93
Total
5.68

Test Results

Thermos v3 started with water at a temperature of 90°C in it and ended with 50°C after 50 minutes. This was a drop in 40°C/50 minutes or -0.8°C per minute which is much better that Thermos v2. The main thing I noticed during this test was that, compared to Thermos v2, the outside of the thermos was much cooler. This was probably due to the fact that the chassis provided more insulation, which prevented heat from conducting to the outside of the Thermos.

The Final Product

The final product ended up being Thermos v3 because it had all of the qualities a thermos needs to keep water warm: a reflective inner surface, threaded lip & lid, insulating foam, and an outer chassis. When I went about designing this thermos, I had to keep 3 things in mind: heat radiation, heat convection, and heat conduction. From my research, I found that to prevent heat radiation you need a reflective surface. To prevent heat from escaping through radiation, I used an aluminum canister for the inside of my thermos (since the interior is somewhat reflective). To prevent heat loss from convection, I figured that I would need to stop all fluids from escaping my thermos because these fluids, air or water, could bring heat with them out of my thermos. To stop heat loss from convection, I 3d printed a threaded lid and lip to contain all fluids in my thermos. Lastly, I needed  to prevent heat loss from conduction. In  my research, I found that to stop conduction you need to make sure that you have insulation or no air in between 2 walls, so that heat cannot conduct through the chassis of your thermos. Knowing that I wouldn’t be able to make a vacuum, I decided to go with insulation in the form of foam and an extra, non conductive chassis. With all of these features together, my thermos was able to only lose 0.8°C per minute. If I was to do this project again, I think I would try to make the thermos smaller so that the water has less surface area to conduct heat out from, and I would try to create a vacuum to stop further conduction.

Core Competencies

 

Weather Reading 18/12/19 1:00pm

Weather Predictions

From what we gathered from the weather maps, we saw a sort of swirling weather pattern centred on a low pressure zone move  above our area but come back down towards us. We think that this will cause more clouds to form above us causing precipitation, and maybe it will get a bit cooler due to the cold front in this vortex.

Weather Reading 17/12/19 12:30pm

Weather Prediction

Yesterday we predicted that the warm front would come in, and we were right, it did cause it to be warmer today and continuing the weather patterns we’ve been seeing. We predict that the cold fron that is south of us will move in causing it to be cooler tomorrow. We also think that the occluded front that came to our region will produce more nimbostratus clouds and  continue the precipitation and cloud cover we’ve been seeing. We also think it will be more windy tomorrow from this cold front.

 

Climate Zones

 

  • Explain how world temperatures and precipitation are changing.

Based on the info we gathered, world temperatures are rising, and so is precipitation. We think temperatures are raising because of the greenhouse gasses we are putting in our atmosphere and a result of this is that more ice is melting, creating more precipitation.

  • What conclusions can you make about how climate change is occurring in different climate zones?

In the cooler climate zones we can conclude that the temperature is raising faster than in warmer climates, and the precipitation is rising. In the warmer climate zones, we can conclude that the temperature is raising and the precipitation is decreasing.

 

 

Weather Reading 16/12/19 1:20pm

Weather Prediction

Since Friday, the low and high pressure zone moved in and out again like we predicted, and this caused rain. From today’s weather map it showed the low pressure zone moving in and out, a high pressure zone move up, and it showed a occluded front move past us. We predict that there will be a more rain, and more wind tomorrow and because there is a high pressure zone moving up, and this will cause rain.

Weather Reading 13/12/19 1:20pm

Weather Prediction

Since yesterday, the low and high pressure zone moved in like we predicted, but not enough to cause rain. From today’s weather map it showed the low pressure zone moving in and out and it showed a stationary front move past us. We predict that there will be a sprinkle of rain, and low wind tomorrow and then clear up because the low pressure zone isn’t getting close enough to cause rain, and because the stationary front is now past us.

Financing a CyberTruck

Conclusion

From this project I learned that there are hidden costs with financing a vehicle. First you have GST and PST which raise your price by 12% and second you have interest rates from borrowing money. In my opinion, purchasing a vehicle is the best option because you are not tied to any contracts that come with leasing a vehicle, and you get to do with the vehicle what you want.

Core Competencies

From this project I improved my critical thinking CC’s. Before I did this project, I thought that interest was just added on in the end, but my thinking has changed because now I know about compound interest rates and how they work. There are these hidden costs with everything you buy and now I am aware of it.

B.C.’s Fishing Industry

1) Choose a species of fish and explain which ones you should consume and which ones you should avoid.

Sockeye Salmon (my favourite)

Based on the information I got from Ocean Wise, I found that the species Gillnet, Purse Seine, and Troll that are caught in the USA: Washington, Oregon and California should be avoided. In the fisheries in these areas, the farmed salmon are supplemented with hatchery fish which get to intermingle with the wild variety. When this happens the fishermen can accidentally catch the wild fish, which are an endangered species. Therefore, to prevent the extinction of the endangered species of that area, those fish should be boycotted.

2) With reference to the video “Salmon Confidential” and your own research about the advantages and disadvantages of salmon farming, assess how sustainable aquaculture is.

When fish are farmed (aquaculture), the close quarters of the fish allow for the rapid transmission and mutation of fish diseases. These fish are farmed in pens that are able to interact with the wild fish, and thereby, transmit the diseases that are produced to the wild variety, which kills most of the wild fish. If this continues It could kill all of our fish: farmed, and wild, therefore, I would say that aquaculture is not sustainable. The advantage of aquaculture is that it gives fish farmers a guaranteed “harvest” and they are able to control which variety the get, wile “protecting” wild populations. I think the way to make aquaculture sustainable is to only raise the fish to a young age and then release them into nature to go out into the ocean and come back to spawn. That way the fish are able to be more dispersed and have a much reduced chance of getting diseased. When the fish come back to spawn, the fisheries can just catch them with a large net, prepare some for consumption, and let others spawn for them to raise. This way we let nature do most of the work for us and we put more fish back into the ecosystem.