Got plans to complete the solar panel I started two years ago. I have all the parts, just need to solder all the cells and wire it together. I’ll get to in August and have an update post here.
This week I gave a demonstration of the egg in the bottle to my classes. This is a favorite demo and I always enjoy doing it. This is a good demo when learning about pressure. To start, burn a piece of paper and put it into the bottle and quickly put the hard boiled egg on top. As the fire goes out, the pressure inside goes down and the higher pressure on the outside pushes the egg in.
Here is a link to my last science lab- the hexaflexagon, which we did last week and you can see the video to learn how to construct and add content to the hexaflexagon.
I have seen this egg demo using a small water balloon and it works the same. To get the egg out, you can try to blow into the bottle which has never worked for me. I usually use an Alka Seltzer and water to pop the egg out. I have also used putting the bottle under hot water to warm the air inside the bottle to expand and push egg back out.
Extensions and discussion
It’s difficult for students to visualize a change in pressure until they see this demonstration. Some of the students have experience going under the water and experiencing increased pressure in their ears, and that helps to understand the concept. For the egg here, it’s the pressure difference that pushes the egg in.
Also, be careful to explain that the lack of oxygen alone doesn’t “suck” the egg in. After I question the students, I explain how the egg goes in and then have them explain to their lab partner. At the end of the class, I have them write their explanation on paper about the egg demo and hand it in so I can check for any misunderstanding.
Making and encoding the video
Here is my latest video on the egg in the bottle video. Again, I used iMovie and since the demo is short, I used a movie trailer. This worked out well as the audio has music and the audio from the classroom was very chaotic. I encoded the flv video as the highest level, which gave me a file size of about 39 meg.
This week we built hexaflexagons in class and added science content on each of the four sides. I thought since the water cycle has four main vocabulary terms, it would be creative to put one vocabulary word on each of the four sides. We also used this for the layers of the atmosphere. Hexaflexagons have four sides and can be constructed with only one piece of paper.
This activity builds enthusiasm for learning science and is a good hands-on activity– much like the great bag of science. See the video gallery for all the science videos here.
History of the hexaflexagon
I first learned about hexaflexagon from Martin Gardner when I was in college. In his book, Mathematical Puzzles and Diversions, Gardner shows a few different ways to construct a flexagon and hexaflexagon. Even though Gardner wrote about the hexaflexagons, others are given credit for their discovery. A graduate student named Authur Stone, while at Princeton University, created the first flexagon by playing around with some paper in math class.
This is a fun activity to do when you have four of something. I also did this with another science class with the layers of the atmosphere.
Here is the video on how to construct your own hexaflexagon. I made this video with iMovie and did a voiceover to give directions on how to construct the hexaflexagon. I exported with mpeg-4 as a Quicktime movie and encoded to flash using iSkysoft Video Converter.
How to fold the hexaflexagon
Start with a piece of paper with the length twice as long as the width. From there, follow my video instructions to complete your own hexaflexagon. Students can add content before or after it’s done. We have made both small and very large hexaflexagons in class over the last few years. Using colored markers is easier that colored pencils as the markers don’t press in on the paper. Remember, the better you make the creases, the easier the hexaflexagon will turn. Watch the video for directions.
This week my classes researched and made a volcano to demonstrate to the class. The project involved making a volcano resume and building the volcano. They were to present to the class about the volcano and demonstrate how the volcano works. I only let them use baking soda and vinegar because of safety reasons. They can add some soap and a few drops of food coloring to the volcano which will give a realistic look of the lava.
Careful with other solutions demonstrating the volcano
Don’t let them use Mentos and soda to demonstrate the volcano project as this will create a large mess in the classroom and will attract bugs and insects. The Mentos and soda should be done outside on another project. I don’t think using them for the volcano project is a good idea. See my other science videos on the video gallery page here.
Keep the class volcano projects moving along
To help keep thinks moving along, I employ a few strategies for the classroom.
I keep an index card of each group with their names and class period for each volcano project.
I use the index cards to show the order of who is going first and the next six groups.
When the group project is ready to present, I staple the index card to their grade sheet. This helps keep track of what they did and helps me find the location of this group on the video.
I always require 10 points in the presentation for cleanup of the volcano, ensuring that they learn to help clean up.
I made a grade sheet for each group using this rubric from Science Scope. Use it and change it for your need and let me know how it worked for you. Tweet
Last week we did the great bag of science demo in class. In this video, I get in the bag and a vacuum is used to take out the air. The greater pressure on the outside squeezes the person inside. How much air pressure? Well it’s 14.7 psi. That doesn’t sound like much, but is sure feels strong.
I did this activity with all my students and it was a long day yet lots of fun.
If you have any extensions, comments, or ideas let me know in the comments.
I’m taking a mathematics training class after school on Tuesday and I’ve developed a Google form document to gather some responses. Let me know what you think about Club 91, Fast 50 and the peg system given in class.
For videos showing how Fast 50 works, click here for part A and here for Part B
Bryan McClelland, an entrepreneur in Manila, Philippines, is making bikes out of bamboo. Seems like a good idea as there is lots of bamboo available for a raw material. Some of the bike parts are made of metal. His claim is that bamboo has the same tensile strength as steel and a higher strength to weight ratio. He sells them for between 500 and 600 dollars. Check out the video below. So would you ride one of these bikes? I would.
Today was the northeast Pennsylvania regional MathCounts competition. It was held at the Penn State Worthington campus in Dunmore. We left school early this morning, around 7:30 am and arrived at 8:15am. After checking in, the team ate donuts provided by the MathCounts and university.
There were thirteen teams competing. They started with the target round, followed by the sprint round. After a short break, the team round was given. My A team was a little nervous, but it turned out, they did pretty good, taking third place overall. For lunch, we all had chicken and pasta in a room adjacent to the student cafeteria. After lunch, it was time for the countdown round. We has one student finish 4th, but did not advance. During the competition, WNEP Ch 16 arrived and took some video. They had a story on the local news tonight and I have the link below.
Update: Our number 5 student will attend the state competition in Harrisburg, Pennsylvania on March 18th. Congratulations K. , I know you will do well there.
I don’t have cable tv or dish network anymore. I was tired of paying for channels that I don’t watch so I canceled the dish subscription. I usually watch shows on the internet and I also have a Netflix account to watch some movies. I think the Netflix model is the way to go in the future. Sometimes, though, I want to see the local news and some of the local sports on the tv.
When the tv signals were changed to digital, it was possible to get a digital converter so one could watch the local shows. I bought the converter at Target and a digital antenna. After I got it all hooked together, the reception wasn’t that great and I only got six channels.
After reading and watching some videos on the internet, I decided to build a antenna out of old coat hangers. I watched three videos on how to build the antenna to get the basic instructions. Here, here, and here are the videos I watched.
I then gathered all the supplies and built the antenna in a few hours last Saturday. It was not that hard at all. After putting it outside, I was glad to see that I now receive 12 channels with very good reception. In the spring, I’ll put the antenna up higher to try and get a few more channels. I may also put some foil backing to increase the reception.
A closeup view
So if you’re looking for an inexpensive antenna for local channels, give it a try.
Here is a cool website where Robin guesses the gift you are thinking of. Take a number between 10 and 99 and subtract the first and second digit. Then use this number to find the corresponding gift. Just think of the gift and Robin will guess what it is.
Click the image to go to the site and give it a try. I’ll give some hints on how this works in the comments. Try it a few times and see if you can find the number theory behind Robin.
