Here is the criteria for their project:
As a way to showcase their understanding, students are creating videos to serve as a Public Service Announcement to answer the driving question for our unit: How Can I Smell Things from a Distance?
Here is the criteria for their project:
Now that we've figured out how phase changes play a role in smelling things from a distance, we're seeing how understanding the particulate nature of matter is important in some real-world situations. Here are the scenarios that students had to analyze...who knew we'd see (and smell) science everywhere!?!?! (wink, wink!)
Now that we figured out all the different ways odors can be different from one another, we're figuring out how an odor can change so we can smell it!
Using ammonia (NH3) and indicator paper at different temperatures, we're seeing how evaporating rates can affect how many molecules enter the air and eventually our noses. It's not necessarily the strength of the scent, but rather how many of the scent molecules are in the air due to heat energy!
So we have figured out some pretty important things about atoms and molecules. We're building models of them to drive home some ideas! And we're starting to really see how odors can be different from one another at the molecular level.
Students were also challenged to draw two molecules that could prove a point: that two different substances can smell different and be made of the SAME atoms!
So after smelling a WHOLE bunch of smells and looking at these letters and numbers associated with them, we figured out a bunch of things:
1. Different smells CAN be made of the same atoms. In our case, we saw C, H, and O repeatedly!
2. Different smells, while made of the same atoms, can have different amounts of those atoms, like 8 of C or 10 of C.
3. Some smells may have all the same letters and numbers but be TOTALLY different smells. We figured out that they must be arranged different. And we drew some models to think about this.
We had a great discussion about how some of the models didn't show connections between the atoms and what this must mean about the odor. In the end, we've still got some work to do about all those letters and numbers and how they relate to both why things smell different and how smells can change over time!
After establishing consensus for how we smell something that is going through a phase change from a solid to a liquid and then to a gas, we began to think about how some things we smell may NOT be going through an obvious phase change due to heat increasing.
Students watched a demonstration today...and here are the results!
We had a big discussion about what must be happening in order to get the indicator paper suspended at the top of the flask to change color, especially knowing the flasks weren't sitting on a hot plate or other heat source. So what exactly does cause the liquids to evaporate?
While we all agree that matter has mass and volume, we're still a little curious as to why we smell something that's a solid, especially since we're thinking something (even with the smallest amount of mass and volume) has to be entering our noses.
But what we don't get, is how can we smell something that isn't heated. We watched as menthol was heated and cooled and had a great discussion (and review) about phase changes and what drives them (increase/decrease in heat energy).
How does this all relate to when something isn't obviously going through a phase change? How can we explain this? We're using the pHet States of Matter Simulator to help us better understand our thinking!
We noticed and wondered a lot from this simulator, and will work to establish consensus for how we smell something...especially as it relates to phase change (or not?!?!).
We're starting to think even more about air, especially now that we know how changing volume and mass affect what air looks like and what it is able to do. We're also starting to think about how air impacts what we can smell along with how it affects the time it takes to smell something.
A simple demonstrate with adding air to a flask allowed students to see how having an odor, along with air, could possible affect one's ability to smell an odor. Some new questions that surfaced were:
1. Since air takes up space and has mass, we're wondering how odor is in the air. Like, does something have to melt and then evaporate in order to smell it?
2. But not everything melts or gets heated up when we smell it. Does a solid evaporate? We smell solids, but we certainly don't think that they're melting and evaporating so quickly we can't see that. Does air play a role in this?
3. We're still stuck on why we smell some things more so than others. Does air play a role in that? Or is it something about the odor? Do odors have different strengths? If so, why?