Thursday, May 17, 2012
Tuesday, March 27, 2012
Tuesday, January 31, 2012
Maps and Bridges
Is Susan's class we started out identifying all of the bridges over the Huron River on a map of Ann Arbor. We split into three groups. Each group took one section of the river and compared what the map showed to what was on Google Earth. They found several differences. The paper map omitted several smaller bridges and a railroad track appeared to travel on a very long bridge that was actually a long causeway. Next they combined all of the group's results into one master map.
Next we started building our won bridges with straws and paperclips. I challenged them to build a bridge that could span a gap slightly shorter than a single straw length and hold up an orange. The paper clips can only be used to make joints. No paperclip chains. We already had several successes.
And one group I had to kick out so they would go eat some lunch.
I gave Owen a specific challenge to build a triangle out of three straws.
Next we started building our won bridges with straws and paperclips. I challenged them to build a bridge that could span a gap slightly shorter than a single straw length and hold up an orange. The paper clips can only be used to make joints. No paperclip chains. We already had several successes.
And one group I had to kick out so they would go eat some lunch.
I gave Owen a specific challenge to build a triangle out of three straws.
Wednesday, January 25, 2012
An unexpected visit
We had an unexpected visit from Professor Alberdore. He presented a challenge to the 3/4th grade class but anyone in the school is welcome to attempt it.
Monday, January 16, 2012
Equipment and parts to build the AeroGel manufacturing device
While studying energy conservation Mr.B's the class got very interested in a material called Aerogel. Aerogel is the lightest solid know and it makes a very good insulator. The problem is that it requires supercritical CO2 at a pressure 74 time that of atmospheric pressure to make it. Besides the safety concerns the price of a machine that can reach those pressures with a substantial volume is cost prohibitive.
Luckily the students found SeaGel a version of Aerogel that is made from Agar Agar (boiled sea weed jello). I tried to make so but my first attempt looked more like jello beef jerky. The trick is to freeze the Agar Agar and pump all the water away before it melts. That is called Freeze drying. When my first attempt melted before it dried I just made dried jello not freeze dried jello.
My second attempt worked much better but the chamber was small and there was only room to make pea sized bits.
Our next attempt was to try to building a freeze dryer (lyophilized) with two chambers. One chamber for the sample and a second chamber to trap the water that leaves the sample. The idea was to be able to independently control the temperature of the two chambers. The sample would be in an ice/salt water bath to hold it at -20 degrees C. While the water trap would be in a bath of rubbing alcohol and dry ice at -80 C. If all went well the water would sublimate from the first chamber and be trapped in the second. Here is a video showing the parts.
Fun with a vacuum pump. I wanted the students to have good understanding of the vacuum pump that we were going to use in making our Aerogel. So we did some experiments.
Now can we understand it?
Now for water. Boiling?
Luckily the students found SeaGel a version of Aerogel that is made from Agar Agar (boiled sea weed jello). I tried to make so but my first attempt looked more like jello beef jerky. The trick is to freeze the Agar Agar and pump all the water away before it melts. That is called Freeze drying. When my first attempt melted before it dried I just made dried jello not freeze dried jello.
My second attempt worked much better but the chamber was small and there was only room to make pea sized bits.
Our next attempt was to try to building a freeze dryer (lyophilized) with two chambers. One chamber for the sample and a second chamber to trap the water that leaves the sample. The idea was to be able to independently control the temperature of the two chambers. The sample would be in an ice/salt water bath to hold it at -20 degrees C. While the water trap would be in a bath of rubbing alcohol and dry ice at -80 C. If all went well the water would sublimate from the first chamber and be trapped in the second. Here is a video showing the parts.
Fun with a vacuum pump. I wanted the students to have good understanding of the vacuum pump that we were going to use in making our Aerogel. So we did some experiments.
Now can we understand it?
Now for water. Boiling?
Soldering! Who doesn't love melting metal with fire?
Sunday, January 15, 2012
Genetic Engineering 101
Mr. B's class tackles difficult material with teamwork.
In connection with the human body focus the class will be doing an actual cloning experiment. They will take the gene for Green Fluorescent Protein (GFP) from a jelly fish, make 10's thousands of copies of it with the Polymerase Chain Reaction (PCR) then insert that gene into living bacteria with a plasmid.
Obviously this requires an enormous amount of knowledge that most 5th/6th grade students don't have (like high school and college biology). Even reading the experiment description and student manual was difficult because it is full of terms, concepts and methods that they don't know. I took this as an opportunity to suggest strategies for tackling difficult material including summarizing and outlining.
The entire class is now sharing a google document that they can all edit in real time. Each student took responsibility for a few paragraphs. After reading their section many times they are writing a summary in the co-authored outline on google docs.
In connection with the human body focus the class will be doing an actual cloning experiment. They will take the gene for Green Fluorescent Protein (GFP) from a jelly fish, make 10's thousands of copies of it with the Polymerase Chain Reaction (PCR) then insert that gene into living bacteria with a plasmid.
Obviously this requires an enormous amount of knowledge that most 5th/6th grade students don't have (like high school and college biology). Even reading the experiment description and student manual was difficult because it is full of terms, concepts and methods that they don't know. I took this as an opportunity to suggest strategies for tackling difficult material including summarizing and outlining.
The entire class is now sharing a google document that they can all edit in real time. Each student took responsibility for a few paragraphs. After reading their section many times they are writing a summary in the co-authored outline on google docs.
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