Day 31

Physical Science: We are still taking the ACT Aspire with the 9th graders. The kids I did see, we went over the Unit 1 Review. Tomorrow some kids are taking this exam.

Chemistry: It was more Eureka! today. First though we investigates one of the properties of matter that results from increasing the temperature of a substance, which helped lead us to defining temperature.

I did a demo where there are two test tubes of unknown liquids, that upon heating slowly creep up a capillary tube stuck to the top of the test tube. The kids spend 5-7 minutes observing the changes, and then have to formulate a reason for the changes.

Of course the issue is that as the particles in a sample of matter get warmer, they move faster and expand. We are careful to discuss that expanding matter does not mean the matter (particles) get bigger, but rather that the overall substance increases in volume due to particles needing more space to move around. Like a mosh pit.

We watch episodes 19-20 of Eureka! and see that the thermometer was created to use this increase of speed to relate “hotness” of a substance. How warm or cold something is, which is relative and not very scientific, is based upon the motion or speed of the particles. Thus we define temperature.

Physics of Light: This was an awesome day. Today was day 1 of the two day refraction challenges. Below you will find a gallery of what the kids had to figure out.

Because of the number of kids I have, I split them into 3 groups, of 5-6 kids each. They were given 5 minutes at each station to observe and take any notes that they wanted about each illusion. They could NOT discuss it with anyone else in the group. After 15 minutes, I split them randomly into pairs and they had the last 30 minutes to give me their answers. Here are a few:

For the “Ghost Crystal” it does in fact have the same index of refraction as the water, which makes it super hard to see. It gets this way by absorbing water into it, so that it is mostly water.


As for the smiley faces, it is due to the refraction of light through the curved surface of the flask. At best, this is what I think is happening:


Since the light refracts coming out of the flask and bends away from the normal, you can see more of the object than you can when it is in the air. It really is more of a preview of things to come, but I like the illusion and what the kids think is going on.

Grading wise I basically look at if they got it or not, or if they were close. This is mostly to challenge their thoughts on the topic, not to really give them a grade. I love these types of challenges. First, its not homework. Second, its not a WS. Third they get to REALLY put this Physics business to the test. The visual nature of this Physics of Light course makes it really fun in my opinion.

Case in point, check out this little video I shot. This is immediately following them jumping into groups after 15 minutes of total silence gathering their thoughts on each station.


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