Wednesday, March 23, 2011

Science in the shop

My son gave me a day warning that he wanted some help for a presentation he was giving in science class, so last night we spent a couple hours in the shop building and filming. Edson is in 8th grade and his class is working through the fundamental laws of physics. He was assigned Bernoulli's principle. He knew the venturi effect relied on Bernoulli's principle so he wanted to shoot some video of the venturi burner I built for the forge I built him. Edson has been fascinated with blacksmithing, so I built a forge, but back to the science.

Edson also wanted to replicate an exhibit we saw at the Exploratorium. The exhibit consists of air blowing down through a hole. When a disk is placed over the hole it is held up by the air blowing down. Very counter intuitive but an amazing demonstration of Bernoulli's Principle. We used part of the rig  from Lauren's science fair project to measure the terminal air velocity of various objects (old vacuum motor on a dimmer switch). A design borrowed from the Mythbusters (thanks Adam).

How does it work? The increase in air speed reduces the pressure at the area around the hole but covered by the disk. In this area the thin layer of air is accelerated. The reduced pressure of the accelerated air creates a pressure differential. The force of the higher air pressure in the room pushes up on the dis and is greater than the combined force of gravity and the air blowing the disk down.

Thursday, March 17, 2011

Soda Bottle Rocket Launcher

2 liter soda bottle, water, cardboard, duct tape, ballast, air at 80 psi, and 100 yards of range to fly. We create rockets out of soda bottles and launch them as part of the school science fair competition. Last year we launched 120 student rockets. Several teachers use the rockets as part of their science curriculum, dividing students in groups to test one variable each (fins, mass, water)
It started when I volunteered to help out with some science demonstrations in my son's 5th grade class 3 years ago. I brought in some demonstrations for the class. After the presentation I was asked to play the "Mad Scientist" during the "Fun With Science Night" demonstration. Fun with science night is the kickoff event to the science fair. The goal is to get kids excited about science and participating in the fair.

Along with the science fair the school has competitions that included soda bottle rockets. The launcher used previously by the school was not available. A fellow parent volunteer (an Engineer from a Northwest aerospace company) and I were recruited to each build a launcher. Two launchers would give us more capacity during the increasingly popular competition.
The Launcher

Bottle Latched

Bottle Unlatched
I decided to make the launcher building my own competition, and started building a 4 pad launcher. Not liking the PVC launcher designs on the internet, I wanted something that would take a beating year after year.
Test Launch

120 Rockets-Post Launch
In the end out my fellow builder did not complete his launcher. My launcher works well and the rocket launch has increase in popularity to the 120 rockets we launched last year in addition to the 70 popsicle stick bridges and science fair projects. This year we are adding mouse trap dragsters.

Monday, February 22, 2010

Ping Pong Ball Canon

I test fired my ping pong ball canon. This is an 8ft length of PVC pipe which is sealed on the ends with mylar held in place with a coupling. The air is drawn out with a vacuum pump. The Ping Pong Ball inside at one end. The mylar is punctured at that end. The air rushing in to fill the vacuum pushes the ball down the pipe and through the mylar at the other end.

Next I will build a rack to hold a few aluminum cans. Marc “Zeke” Kossover demonstrated his vacuum cannon at the Make Faire in 2009. It was very impressive to see a ping pong ball blow a hole in an aluminum can. I think it will be a hit at the fun with science night. A loud bang with some minor distruction is sure to be a hit. I wonder what a golf ball will go through?

Sunday, March 8, 2009

Cloud Chamber

My cloud chamber adventures started with the LHC Rap video on YouTube that a friend at work shared. I forwarded the link to my son's teacher the week before the first parent teacher meeting of the 2008-09 school year. Last year I brought demonstrations of oobleck and sodium acetate for a presentation. She invited me to come back this year. It is a 5th-6th grade class. In science this year they were studying models. The LHC was a perfect fit, trying to find the Higgs Boson and prove the standard model. The video was a good start but I needed to bring some kind of demonstration. I thought of a cloud chamber.

My search for information on cloud chambers started with but there was nothing. I did find some cloud chambers for sale, websites about cloud chambers, and YouTube videos demonstrating traces in cloud chambers. Then I found Holly Batchelor's video. It had step by step instructions. It was just what I needed. I set off to work. I used an aluminum griddle cut down to fit in the foam cooler that I cut down to hold the dry ice. I used the reptile house Holly used and painted parts of it black instead of sewing the drape. Add some alcohol and dry ice and my kids and I were watching sub atomic particle traces in my garage. Very cool. I shot some video and uploaded this one to YouTube. This video has a clear trace at the end that I believe it is an electron initiated by background radiation.

I also was able to produce Alpha particle traces by placing Americum 241 from a smoke detector in the chamber.

I ended up doing two presentations at school one group included my daughter's class and one included my son's. Some of the kids were interested in the LHC and the cloud chamber, and some others were fascinated by the dry ice bubbling in water and the other dry ice I had filling up a large mylar tube. I hope the kids got something out of it, I know I had fun.

Wednesday, September 10, 2008

Summer Vacation 2008

On July 19, 2008 I dropped Edson off at SeaTac airport to fly to Toronto Ontario with one of the local staff from Keewaydin and a handful of other kids. The rest of the family's adventure started after work on Monday August 4, 2008. The trailer was packed and ready to go. We just needed the perishables and ice in the cooler and we were ready to go. With the cooler loaded the family in the truck I hitched up the trailer. Before we pulled out I did the "light check" to make sure I had taillights, turn signals, and brakes. I did not...

I checked the plug at the back of the truck the bulbs to no avail. I turned off the truck sent the family inside and drilled out the rivets on the back of the trailer. With the back off I could find no obvious loose connection. I drove to the auto parts store and picked up a trailer wiring harness, stripped out the wiring under the trailer and installed the new harness. We left about 2 hours later than planned.

We drove from Seattle East on I90 and I94 through North Dakota and the twin cities to Waupaca Wisconsin to visit Grandmother Stephens. She is not a blood relative, but a very close family friend. From there we drove north through Michigan and crossed in to Canada at Sault Ste Marie. We drove across the border past midnight. My favorite question at the border was "Do you have any live meat?". That one confused me...I had no live animals, so all the meat was dead. I answered that I had some bacon... We were allowed into Canada anyway. That was 3 long days and one Monday evening of driving. It took toll 4pm the following day to get to the dock on Lake Temagami and ride out to Devil's Island and arrive at Keewaydin.

The ride out in the evening was beautiful. The food at Objibway was wonderful. Objibway is the lodge at the north end of Devil's Island for adults. Mostly parents, but anyone can stay there. We stayed on Paul's Island (less than 100 yards from Devil's Island). Our cabin was a rustic log cabin with gas-lights and a wood stove for heat. For water there was a convenient lake surrounding the island and a pitcher on the table. The toilet on Paul's Island is a two seat outhouse with a great view.

We had the option of using the classic wood canvas Keewaydin canoes to get across, but with my mother and two kids we opted for the motor boat. We slept well and were glad to not be on the road. The rain started that night. We motored over for breakfast Saturday morning in the morning in the rain. After breakfast we walked to the South end of the island to watch sections paddle in. The video to the right is from Edson's section (Mattawa) paddle in.

After paddle in we had a chance to catch up with Edson. He went back to our cabin for awhile and we all went back for the Outpost campfire stories. After some great stories we had to walk in the rain and dark back to the north end of the island and motor back to Paul's Island in the wind and chop and complete darkness. I have very little boating experience, but we made it.

The next day included a race around the island and guncanoe competition where the older campers show off their skills tumping, loading, and maneuvering their canoes. We had dinner with the kids and the evening ended with some awards and campfire stories in the rain. We left for Paul's Island a little earlier in the evening and we used the boat to get back and forth from the North and South ends of the island.

We headed out the next morning. I left with my mom and dropped her off at the train station in Temagami. I returned to the dock to pick up the rest of the family and start the second part of vacation. We stopped in North Bay to eat at Tim Hortons. We were curious since all the comedians on CBC (Canadian TV channel we get in Seattle) make fun of Tim Hortons. It was OK but nothing too special. With that I may not be let back into Canada.

We drove through the small town of Mattawa and visited their museum. They had lots of great artifacts and information about Grey Owl. We stayed the night at in Canada and passed into Vermont the next day.

Wednesday, May 14, 2008

Make Faire San Mateo 2008

The whole family drove south to the Bay Area to attend the Make Faire this year. We were hoping for a chance to compete in the king of fling competition, but they did not hold the competition this year. We visited the Exploratorium on Friday before the Faire. An amazing place to visit and an outstanding gift and book shop.

Check out the Make Blog for a good overview video of the Faire. The highlights of the two days included motorized cupcakes, popping acetylene soap bubbles, SparkFun booth, Evil Mad Scientist Booth, mousetrap, Steam punk stem buggy, Adam Savage's Presentation, Home Chem Lab Presentation, 5 Dangerous Things you should let your kids do, the Chumby booth (I purchased one for my 8 year old daughter, really it was for her), and the maker store.

Tuesday, May 13, 2008

Sodium Acetate

My son's 5th grade class studied Solutions in science. At the beginning of the year for open house the teacher mentioned the topic I had recently seen the PopSci post and a Make post about a super saturated Sodium Acetate solutions and was looking for an excuse to play. The teacher was interested but when I offered to prepare the supplies for her to demonstrate she suggested I come in and give the demo. I accepted.

I ordered my crystallized sodium acetate from United Nuclear. Look for reruns of Wired Science to see a story about them. I later realized making the crystals from Baking Soda and Vinegar at home is very simple and much cheaper.

For the class presentation after I did the demonstration showing the clear super saturated solution turning into a solid as I poured it out I shared what was occurring and the chemicals involved. Asking who had made sodium acetate at home resulted in silence and blank stares. I followed that with the recipe of mixing sodium bicarbonate and acetic acid. Again blank stares. I said let me demonstrate. As soon as I poured the vinegar into the baking soda they all knew exactly what it was.