Best Thermo assignment ever!

Made you click ;)

Then again, that is the point of this assignment. This year in my thermodynamics unit I ended up with two half days open (I couldn't rearrange them to make it a full day). I started making a list of topics related to thermodynamics applications seen in the real world that I don't usually cover. I wanted students to research these topics and share what they learned but was missing the buy-in. I found the topics interesting but knew looking at the list my students initially might not. They needed something to entice them ... something that would make them click on the topic if they were reading it on their phones. I needed some bait to hook them in ....

Click bait headlines!

[You may have seen that coming]

So I created this assignment (pdf or google doc) for groups to work on on the first of the half days. Students thought the click bait headline requirement was hilarious. Some topics required a bit more explanation to guide them in the right direction. For example, the second question about boiling water could go one of two ways. Some groups went the way I was thinking and found that most diseases and bacteria are killed around 80 degrees Celsius while water boils at 100 degrees Celsius. Raising the temperature an extra 20 degrees Celsius is a large amount of energy to waste. Some groups looked at pollutants and said that boiling water did not remove them and in fact can increase their concentration as water boils off.

Some topics, like the popcorn kernels, were high interest but lower level. Harvesting heat from roadways had more diverse answers depending on which of the possible collection methods they were more interested in. I also noticed that students tended to use more vocabulary from the unit in their explanations. The "Urban Heat Island" questions threw students at first; many thought it was merely a sum of body heat in such a densely populated area.

The second half day was spent sharing the responses. Groups read their headlines and summaries. This did  not take as long as I expected, so we watched some extraneous thermo videos. I think that the activity could be expanded to require more details like pros/ cons, next steps, potential costs of solutions, etc. This would not work for the popcorn question, but I'm sure with some time I could think of some more higher level topics.

A few examples of the results are below:

Brainiac clips

Every year, for as long as I can remember, I've shown a clip from the British show Brainiac that makes a giant pendulum mirroring the in-class bowling ball demo. My downloaded copy is grainy and pixelated so I decided to try and find a better version. I downloaded one Brainiac episode (Season 1, episode 3) with the intention of editing it down to the 4 minutes or so that I wanted. I ended up watching the whole 40 minute episode and editing out six clips to use in my classroom. Not too shabby for some fun TV time.

Conservation of Energy and a giant pendulum:
Well explained and stands alone well.

Oil Slip & Slide:
Even really slippery surfaces have a coefficient of friction that slows down moving objects. You could have students estimate it using the values given in the clip.

LN2 filled water bottle:
Quick example of pressure, boiling and of course liguid nitrogen.

Does a duck's quack echo?

Sometimes students just won't believe you unless they see it for themselves. Or in this case hear it. 

Don't microwave a CD:
#ThingsThatShouldGoWithoutSaying

Playground G forces:
Brainiacs (the volunteers and staff that put on the science of the show) try to get the most G forces possible out of a playground merry-go-round. You could get more but they are limited by human power.

Iron in cereal:
This is an easy demo to do in the classroom but it does take some prep, the right cereal, etc. This is a super short clip that demonstrates it if you don't have the time.

Now I want to watch more of it. Besides the energy pendulum the only other clip I have seen prior to this was another all time favorite, "The Electric Fence." It is pretty much all the things you wish you could do in your classroom but couldn't:

Update: For an exhaustive video demo lesson on the Brainiacs: Electric Fence clip, see this old Blog of Phyz post:

Electric Fence Redux

Air Pressure Rocket on a Hot Day

I use my Arbor Scientific Air-Powered Projectile rocket every year. With my Conceptual Physics students we take the data as a class, determine the average time and use that to calculate the maximum height. With my older Physics students this year I decided to open it up. I told students how the rocket worked and asked them to write their own procedure to find the maximum height and initial velocity. Not surprisingly, groups independently determined that the best way to determine this information was to time the rocket's entire flight and then use half that flight time to determine the rest. Once students determined how they were going to test it, we went out to an open space and launched the rocket five times with the "low" washer and five times with the "high" washer. Each group collected their own data for their calculations but then I collected their results for each period.

I noticed during three periods of trials that the rocket launched sooner later on in the day. In the morning the rocket consistently launched after 5 pumps with the "low" washer and 7-8 pumps with the "high" washer. By the afternoon it launched after barely 4 pumps with the "low" and 5-6 with the "high." It was a warm day so temperature definitely played a role. Looking at archived temperature data for our area it was about 82 degrees for the first period's data, 90 degrees for the second and 97 degrees for the third. If you look at the consolidated data for all three periods you can see that the maximum heights and initial velocities decrease as the day went on.

 

My last period did get a chance to try the "super" washer. Now I wish I had tried it in the morning for comparison when it was (relatively) colder. 

There are lots and lots of things you can do with this rocket. There is an additional set of wood angled blocks for consistent angled shots you can purchase.

Here lies a drinking bird

In our Thermodynamics unit students observe a drinking bird's motion to try and figure out how it works. I ask them a series of questions to guide them but several come to the wrong conclusion. Now I set up drinking birds with hot water, ice water, isopropyl alcohol and one without a cup on the second day. I ask students to apply their original explanation to the second day and that helps a few more of them. I tell students that a doctorate level thesis was written on this seemingly simple bird so it's ok if they need a one time to understand it. There are several common wrong answers:
- The liquid from the cup goes into the bird through the beak.
- Heat from the room expands the gas in the bottom bulb forcing the liquid up  (Close, can be seen if you hit the bottom with a hair dryer or hold it in your hand briefly. Try to avoid doing this in front of the kids to avoid this misconception.)
- The liquid inside the bottom bulb is heated by the room and expands.

The birds are occasionally handled too rough. I mounted one such poor bird and will add a little tombstone under it. I scraped the felt off part of the head so students could see how the top bulb was connected to the bottom one. I would like to take all the felt off of a functional head for students to compare as well. I had to add some hot glue inside the head (the cloudy white you see) in order to keep the broken fragments together. I hope to add a plaque:

Here lies a Drinking Bird

Devoted and tireless worker who only wanted

to help others understand fluid expansion and heat flow. 

Too much?