Friday, December 21, 2012

Model Circulatory System | 7th Grade Science

Do you remember learning about our circulatory system in biology class? If so, you may remember looking at diagrams of the heart, memorizing the names of the various valves and chambers, and understanding how blood flows through the system. But in our 7th grade science class, we decided to try something different.... something a little more "Bourn-ified"!

How might we build a model of the circulatory system that would allow students to simulate the flow of blood, the contraction (aka the "pumping" of the heart muscles, and gain an appreciation for how the sequence of events has to be precisely orchestrated in order for the system to function? Christina Nawas, who has done a number of projects with us this semester, came to us with this original question and we rolled up our sleeves to design a hands-on project to do exactly that.

After some brainstorming, Diego got to work building a prototype using plastic tubing to model arteries and aortas and squeeze bottles to model the chambers of the heart. He first started by playing around with those plastic squeeze bottles that you usually see holding ketchup and various sauces at restaurants, but eventually realized their seals don't hold up and leaked water everywhere when squeezed. Tiny travel-size screw-top bottles ended up working better.

The next challenge was finding one-way valves to model heart valves. Diego started by designing some using laser-cut parts and pieces of thin rubber but these didn't end up being as one-way as we'd like. Then one day in the lab, as the two of us were wrecking our brains trying to solve this problem, I randomly wondered aloud whether people who keep fish for pets need one-way valves for their aquariums. A bit of Googling and a trip to the pet store confirmed our suspicions and thanks to Amazon, we were able to get a large batch of these valves in time for class.

To scaffold the activity, we started by asking the girls to build two-chamber hearts in pairs, using a kit of squeeze bottles, plastic tubing, connectors, and one-way valves. Christina also took some time to explain that the type of two-chamber hearts we're building are different from those found in nature. (We were building hearts where one chamber is the left and one chamber is the right; in nature, two-chamber hearts are usually divided into one ventricle and one atrium instead.) Then they had to work together to get "blood" (clear water, for the sake of not having our lab look like a massacre at the end!) pumping through their model system.

After the two-chamber hearts were built, we then asked the girls to get in groups of four and challenged them to put together four-chamber hearts! Again, after they got their system wired up correctly, with all the valves facing the right way, they had to test it by working together to pump the heart chambers in a proper sequence to get blood to flow. Some groups even came up with chants to help coordinate the proper pumping sequence!

Even though everyone got slightly soggy, it was so great to see how this activity really allowed the students to learn about how the circulatory system works! Don't believe me? See for yourself!

Saturday, December 15, 2012

Science Saturdays: Light-Up Holiday Cards

One of the things you may not know about the Bourn Lab is that in addition to being a space for tinkering and hands-on projects during the school day and the home of Gatorbotics Team 1700 after school, we occasionally open up the lab to the wider Palo Alto community by participating in Science Saturdays throughout the school year.

Mary Hurlbut, our 6th grade art teacher and Castilleja's site director for the Peninsula Bridge program, and intern Ruby Moreno (Casti alum alert!) work together to organize on-campus events for younger girls from the local community to get them excited about science and engineering. Usually, a hands-on activity in the science labs is paired with a related activity in the Bourn Lab. The extra cool thing about Science Saturdays is that the whole event is supported by our robotics girls!

Back on 12/1, we kicked off the year's first Science Saturday with a holiday-themed event. After a fun and slightly chaotic name game involving tennis balls, the group split up. One half went to the physics lab to do a simple circuitry activity involving batteries and light bulbs. The other half headed down to the Bourn Lab to work on Light-Up Holiday Cards, which also involved ... you guessed it, batteries (little coin ones) and lights (LEDs in this case)!

The girls, both younger and older, had such a great time and each of them got to take home a light-up holiday card. We can't wait for more Science Saturdays next semester!

Friday, December 14, 2012

Intro to GoGo Boards | 6th Grade Science

How would you design the logic of a traffic signal?

This was one of the challenges we posed to our 6th graders, as part of a two-day activity we did during their science class. On the first day, Sarah Barnum (6th grade science teacher) and I, with help from Ann Greyson (computer science teacher) and Megan Chiou (our teaching intern), took students through a quick lesson on inputs and outputs and then a tutorial on how to use GoGo Boards. On the second day, we asked them to use what they learned to design two everyday devices: a night light and a traffic light. At least one of their designs must incorporate some type of input (sensors) that would control the outputs (lights).

In developing this activity, the first hurdle we faced was that GoGo Monitor, the standard software for GoGo Boards, only runs on Windows PCs and our campus is for the most part a Mac campus. In the past, we kept a set of Windows laptops in the lab for this exact purpose. But we wanted to try something different this year and find a Mac-friendly way to allow students to play with GoGo Boards.

(I should probably mention at this point that a main reason for trying something different is that I'm a big believer in making technology less "precious"/as accessible as possible and tend to opt for solutions to that effect. Especially for something like programming and GoGo Boards, I want students to have the software on their own computers, so they feel empowered to explore and tinker further on their own if they want, maybe by borrowing GoGo Boards from us or buying their own, and won't feel that this is something they can do only if they came to the lab.)

In the end, we found a way to control the GoGo Boards using a cross-platform program called NetLogo. In fact, NetLogo turned out to be a great solution because it allowed us to write up a tutorial, based on the original FabLab@School activity, directly inside the program that students can follow along.

Our 6th graders loved playing with the GoGo Boards and were excited to think about how their night lights and traffic lights should work. Some thought that night lights should be motion-activated while others thought they should sense the amount of light in a room before turning on. And for traffic lights, some groups incorporated mechanical switches, which would be placed on the road and activate the traffic light sequence only when a car rolls up and triggers the switch.

Check out the video below for a traffic light demo:

Some girls got so into programming and GoGo Boards that they kept asking Sarah if they'll get to play around with them in class again. So by popular demand, we decided to lend the 6th grade science classroom a couple of GoGo kits. Now, whenever there's some downtime, girls who want to can tinker with GoGo Boards more on their own.

Not exactly a quantitative measure but I would certainly call that a sign that GoGo Boards are a hit!