Reflection and refraction

This term I did the refraction demonstrations on Wednesday, including the placing of a one dollar coin on top of a towel and under a beaker filled with water. The top of the beaker was covered with a ceramic floor tile. I then asked the class to come up and determine what coin was under the bottom of the beaker.

Due to total internal reflection at the bottom, and refraction at the sides of the beaker, the coin is invisible.

Then I put the coin in an empty frisbee on the table. From the other end of the table the students could not see the penny. Then I added water until the frisbee was full. The penny could now be seen.

I wrapped up Wednesday using the laser and running it through a semi-circular dish of water. I did also try to shoot the laser through a plastic tube filled with water - not very successfully. Then I tried to get the laser to run inside the water cascading out of a hole in a 5 gallon water jug. Other than making the floor wet, I accomplished little. I need something more sophisticated to demonstrated the fiber optic total internal reflection effect.

I also demonstrated the image forming ability of convex magnifying lenses.

Moving the demos up to Wednesday worked well for keeping the laboratory focused on the image and object distance relationships. Works better than having these on Thursday. What was sacrificed was the optics lecture with coverage of hyperopia, myopia, presbyopia. This term was also the first term that I showed Bill Nye's optics DVD. It is somewhat scattershot, maybe too scattershot to be useful. On the plus side the DVD did set up the Wednesday demonstrations. Not sure if I should again use that DVD.

Measuring the apparent depth of a penny under water to determine the index of refraction of water.

LoriAnn and Tulpe determine the apparent depth. This laboratory still leads to a

Ashley measures the object distance for a figurine.

Rose Ann.

Emily, Eugene

Trishia steadies the mirror tile

Vengelynn
Posted by Picasa

Comments

Post a Comment

Popular posts from this blog

Plotting polar coordinates in Desmos and a vector addition demonstrator

Image
In an earlier post I noted that Desmos did not directly plot polar coordinates. Not only was I incorrect, but Desmos responded to my blog to correct me! Although I had at some point seen that one could define a function f(x)=3x+5 and then have Desmos calculate f(6), I had not absorbed how this might be used to plot polar coordinates. The above works beautifully . Realizing that I could effectively program Desmos, I applied this thinking to demonstrating how to add two vectors when given the magnitudes m and the direction angles theta. The graph calculates the i and j components for the two vectors and then adds the vectors, graphically displaying the result while also providing information on the magnitude and direction of the vector sum. m1 and theta1 are the magnitude and direction angle for one of the two vectors, m2 and theta2 are the magnitude and direction for the other vector. All four are dynamically interactive and can be changed. The diagram purports to illustra
Read more

Setting up a boxplot chart in Google Sheets with multiple boxplots on a single chart

Image
The  Google Statistics  add-on for Google Sheets can display multiple boxplots in a single chart. The key is the layout of the data. One column should be the variable by which the data is to be grouped, the other column should be the data to be box plotted. Set up the Statistics add-on with the data to be plotted as the variable, and the grouping column as the "by" variable. In this image I had deselected all but the boxplot option, the result was the appearance of the Moment, Standard errors, and Confidence intervals options. The default is apparently a 95% confidence interval for the mean. The result is multiple boxplots on a single chart with a common scale. The new tab that is created also quotes 95% confidence intervals for the mean. Note that as of 2018 the Google Statistics add-on cannot be found by search in the add-ons. In addition, as of May 2018 the add-on no longer verifies, possibly due to the add-on not having been updated since August 2017. One may ha
Read more

Traditional food dishes of Micronesia

Image
Clara, Jennette, and Joanie presented ground hard taro cooked in an umw, effectively a hot rock oven. Pohnpeian: rotama. Pingelapese: sero. Mwoakillese: rodma. Mortlockese: Amahd. Kosrae: rodoma. After cooking in an umw the rotama is pounded with the petiole of a palm frond. Rotama is made from hard or swamp taro, known as mwahng on Pohnpei, mweian on Pingalap, pula in Mortlockese, and pahsruhk on Kosrae. In traditional times on the outer islands the women had primary responsibility for tending the taro while the men handled fishing and climbing tasks. Joesen and Noeleen presented fermented breadfruit from the outer islands of Yap such as Woleai and Eauripik. The raw ingredients were actually brought in from Yap, Noeleen prepared the maare.  The leaf wrap is ti leaf - Cordyline fruticosa. Pauleen, Barnson, Trisha, Verginia, Con-ray, and Maylanda from Kitti, Pohnpei brought in mahi umw, koahpnoair koakihr, and uht sukusuk. Above is breadfruit umw, mahi umw, one o
Read more