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July 31, 2014

Electronics: Bigshot camera lessons

The gearbox on the bigshots gives an opportunity to dwell into the energy generation in the camera using a manual crank. I had already demonstrated that only at reasonable rotation of the handcrank the battery charges.

I wanted to give children something tangible to measure so I can connect it back to math (especially decimals as I am in the process of introducing these). For the measurements I needed to introduce the multi-meter. I started with the most exciting feature of the multi-meter, the continuity test and though I had not intended for it to become an entire class the children did not tire of getting materials that they thought would conduct or not conduct electricity. The most interesting choice of elements being magnets.

I next introduced DC voltages. I still find it amazing how much of electronics terminology is commonplace with children. They knew it was called Direct Current, but didn't know why. I called it a battery voltage. We measured various batteries and learnt how to read the voltage rating on the batteries.

With a bit of difficulty with water analogy I have started to use the body and flow of electricity to the flow of blood in the body and the battery as the heart that pumps the blood through the body. The voltage in this analogy is the pressure with which the heart pumps. Children relate it to when they are engaged in a physical activity and their heart pumps harder/faster.

We then measured the voltage of the rechargeable battery of the bigshot camera. We found it to be 4.1 V. The children summarized that what was charging this battery had to be greater than 4.1 V. They were quite surprised when they disconnected the battery measured the output of the PCB was 0 V. I then reminded them that that hand crank was disengaged. On rotating the hand crank they did get a voltage around 5 V (not loaded with battery). 

The Bigshot learning material talked about how the AC from the dynamo gets converted to DC for the battery. I felt that could be something fun to measure and realize the difference between DC and AC. I let the children measure with multi-meter still set in the DC mode for the children to see that an AC gives zero DC. We bypassed the PCB and directly measured the output of the dynamo. It was I who was in for a surprise, the meter read 9 V during one of the turns. I realized that it was only a small DC motor giving un-regulated DC voltage that was being regulated for the battery by the PCB. The pic below follows the link to the images:

I noticed that children are really struggling with indoor images and if you are absolutely still when taking the shot, you can get a few decent shots. Something I need to train the kids in.

A few children had done the demonstration for the class and I thought this was something they could all measure. I brought in few cameras assembled by other grades and we disassembled these cameras. The next day I split the class in groups of two and gave the choice to do the measurement or to assemble the camera. Its little surprise the children wanted to assemble the camera. This was the smallest (2 in a group) and youngest group I had given the task to and they went about it quite nicely. I also found the first broken part (a tooth of gear C) and  the first missing part (an axle) after all the assembling and disassembling by the children.

One interesting mixup was when one group accidentally connected the battery to the dynamo. The hand crank started to rotate and the kids were spooked. Well, it did confirm that we were working with a DC motor as a generator. Here are some images from the assembly:

July 30, 2014

Bigshot: Biology field trip

I had presented BigShot cameras at the teachers meeting at Udavi with the hope that someone will want to pursue it with grades other than 6th and 7th that I interact with.

It was interesting that the first opportunity presented itself through Biology. Geetha the teacher had mentioned that she was planning to take the children out on a field trip to the crocodile park and through it would be interesting to take a few cameras along. It didn't take long before she realized the utility of the children putting together the cameras rather than being given the cameras as it would be instructional and increase the ownership of the instrument during the trip.

As I had worked with these children the last year and they were a little older I gave them the option of watching us build it or building it themselves. I was not surprised when they came back with, we can do it ourselves. The children assembled the cameras at different paces. Most groups needed a little support when they came to the finer components of the camera lens.

Most groups went over the instructions and in most places these are supported well with images so the groups having a little difficulty also had support with the images.

The children enjoyed the session and then went out and took some pics of the school.

The next day they went to the crocodile park and took plenty of pics. The children sorted through some 100 odd pics from each camera and put together an album for me. I've put together a few of these pics that were non-overlapping.

The children also wrote about their experiences with the Bigshots camera. The children found the process demystifying. Some children found reading the manual the difficult part. Most found the actual assembly a lot easier than they expected. Almost everyone was thrilled and enjoyed the experience. At the crocodile park some ran out of charge quite fast (possibly because its not obvious how to turn off the display) and the hand crank kept getting stuck for them. Here are some of their experiences. 

July 20, 2014

Taming Frankenstein

As I progressed towards getting children proficient with both positive and negative numbers the 'target' game got tuned further. I allowed students to put the starting number and guessing the number needed to get to target and as part of meta-cognition test I asked how many children felt they were proficient with integer arithmetic 6 children stood up immediately. Most others were able to do 'sums' on integers, but the idea of subtracting the starting point from a target worked ok in their head with questions like 5 going to 10, -11 going to 7, -17 going to -35 got messy.

With a few commands we transformed getting a user number (which some children were sticking to 'simple' numbers) to a random one and putting in a count for correct numbers. The twist was that the count was zeroed out if you got one wrong. I asked children to show their proficiency by getting to 10. Time not being an issue. Every 5 minutes or so the room will have an aaagghh, oh no as children made progress just to be shot down before they could get to 10. I decided not to tell the children about Frankenstein, but they felt that they had created the game and should be able to beat it. Arc was able to beat her game and was quite pleased with herself. Lets see if the other kids get the same high tomorrow.

Teacher Note:
I've made it a little simpler with +1 for a correct answer and -1 for an incorrect one. A list tracks all the problems where the child was confused so you can look at it in detail once they are done.

July 18, 2014

Gear Up: Lesson using bigshot camera

The children in Udavi 6th grade had assembled the bigshot camera and taken pictures. They had also taken note of some of the components of the camera. We started with the gear box to learn more about gears, how they work and what kind of math they would need to learn to appreciate and predict what happens.

The obvious gears that the kids knew about was my gear cycle. We flipped the bicycle upside down and the kids counted the gears. The kids tried to find more efficient ways to count and finally concluded with 42 teeth. They then went out to count the number of gears. We had seen a couple of videos on gears including Aravind gupta video on making it from cardboard. We talked about whether the smaller or the larger is a higher gear, what the additional gears that are always engaged (derailleurs) do. 

Thanks to the video most kids were able to conclude that the smaller the diameter in the back wheel the higher the gear. When we got to the ratio of the chain wheel vs the back wheel the kids were ok with the gear with 21 teeth for a ratio of 2:1, but got stuck on 28 teeth. It was a note on what we will be learning this year to be able to talk about it by the end of the year.

I also demonstrated with a few gears how we could make a model with different kinds of gears to rotate small (fast) and large wheels (slower) when they are coupled. We then looked at a gear game Kogworks which seemed appropriate and looked at the patters that can be formed and whether the wheels still spin if the number of gears in a loop are even or odd...

One of the kids the brought his toy car and opened it up to reveal that he noticed gears in it. He showed how pulling the wheels back cocks the large gear and releasing it makes the smaller one that drives the wheels of the car move.

July 10, 2014

Making a game...

I had a discussion with the computer instructor comparing teaching children programming (scratch) vs Openoffice in 6th-8th grade. We noted that it is possible that the office tools may have a role to play when they eventually graduate and look for work. We talked about how long it really takes to get a basic hang of what can be done with office and as children what application/interest they would have to build on it. The discussion helped me realize that Scratch allows the children to create something that can interact with them/others vs only present.

I started working on this by making the basic program they were working with interactive. Check teacher note for more details on integer addition.

The children felt the characters they had created real. They were able to relate the movement of their characters from the center of the stage to the left and right in terms of the number line and didn't get all worked up as the previous set of children I had worked with regarding negative numbers.

The kids seemed to be enjoying themselves punching in numbers and checking if they got it right. I asked them if they were really enjoying themselves and they said yes. But, there was no uncertainty or serious challenge and I want's sure if the children were enjoying themselves or if they had found a comfort zone. It was time to stretch.

We made a game out of it by allowing the user to enter a number and then have to reach a target randomly chosen by the computer. This allowed for having to think through where they were and where they needed to go and calculate accordingly. It seemed challenging, perhaps, too challenging for the younger children. When we did a self assessment the elder children felt their best work was to create the games and the younger ones kept talking about wanting to master the game.

In one of the classes, I helped them add a timer. Though they were troubled by the timer when the played the game, they simply could not take it out as they had created the game and it was a cool feature. Creating the game and playing with it were valuable complements to the discussion we had in class regarding integers, in specific negative numbers.

Teacher note:
For addition of integers the interactive program places the character at x=0. The user provides the first number and it moves that many steps and then the user provides the second number and it moves as many steps.

In one grade I introduced negative numbers initially with story of
5-10 where you had only Rs.5 and needed to buy a chocolate for Rs.10 and needed to take a loan from the shop for the same.
We then slowly drifted to Scratch. It was interesting that children are able to see scratch as something real that they control. The children all use their own characters and objects so I guess when I starting talking about what does move x 10 do the children had no issues talking about how you move right by 10 and that move x -10 says change direction to what you were moving before and goes left instead. 

I was careful to position a negative as a turn around (change direction) rather than left as it gave me the option of introducing a double negative as going right.

July 09, 2014

Listening exercise

One of the big challenges I face as a teacher is to keep a class present and engaged. One of the ways to keep children engaged is to have them participate in the class. 

Before taking up algebra the children need to be comfortable with the idea of what the basic operations mean in real life and we were going through these through stories addition and its two corresponding subtraction stories. Some children would state a story while the others would change it. However, I found that a good part of the class was distracted on more than one occasion. They were tuning out to both teachers and fellow students and I felt that it was important for them to understand what it means to listen deeply (vs background conversation).

We did the listening exercise. You work with a partner and think of something you are proud of or is important to you. You ask the partner to role play the person you want to talk to. In the first exercise they are distracted, looking at the time, interrupting you and generally ignoring you. After 30s you switch roles. After a minute make a list of how everyone felt. 
We then listen deeply as if listening to our partners was the most important thing for us at this time. This generally takes a little longer 1 min and then you switch roles for another minute and list how everyone felt.

Here is what we had in class:
very bad very good
difficult very nice
don't feel like talking happy
feel like beating super
angry feel like talking more
tired interested
kill proud


We closed with the realization that each of us have the power to make others feel like the left or the right in 1-1/2 minutes. Part of growing up is that the children can make the choice of how they wanted to listen. Since teachers are also human we also feel like sharing more when we have an engaged classroom.

The children still occasionally drift, but its lesser and there is something to refer back to. It has actually been fairly hot and we are breaking mental patterns the children have had for years so  if more than a couple of kids start to drift we take thought breaks (right and left side of the body doing different actions or breaking mental images if more than one person is drifting).

July 07, 2014

Phone number of a computer

The children have learnt to program with scratch at different speeds and as part of different groups. Some learnt it over the summer. Some children were in a different grade before being part of the multi-grade classroom (15 kids from 6th to 8th grade) and they have all used different machines. One of the issues that cropped up was that a child wanted to use only one machine since the child would have its work on that machine. I had used sftp and other such protocols, but was not sure how to set it up. Also my time beyond the classroom is limited and I am unable to be a sysad. I checked the minumum needed for a file transfer was to start listening to port 22 and this I did.

I thought the children would find it fun to think of communication across machines. I started with a analogy using cellphones. What if you called someone from another person's cellphone and then wanted to save it on ones own phone. The first solution was that one person can read out and the other can punch it in (I wonder if that is indeed the fastest!), within a second another kid suggested that you can SMS the number. Well, the village kids growing up in this connected world age find the cellphone quite intuitive (memo to andriod - you should not need to install an app to SMS phone numbers!)

We then started talking about what is needed to make this happen. We should know the phone number to SMS to, there should be a network and even one that suggested that there should be a battery in the phone. Since the kids brought up batteries we started talking about the SIM card and what functionality it could have. e.g. What happens if the SIM card from a phone is removed? What happens if the SIM card placed in another phone? Again, its amazing how much kids know about cellphones.

We then talked about how cellphones communicate to each other. The kids immediately brought up 'tower' and then how it goes to a satellite and comes back! Ok. Well what if two phones were close by, would they need to go out of their way? We then talked about networks that are connected to each other and at times when no physical network is available signals needing to take off.

I mentioned that the internet is one more network and pointed out that much more can be done other than going receiving data from the internet. We could also send information, including transferring files between machines. I proposed that it was like making a phone call. You needed to know the number of the person who you were calling, they would need to pick up, but then since these were machines talking not people there would be additional checks and balances.

I had installed Filezilla on one of the machines and tried to transfer to the pseudo server. This had worked the day before. I had, however, not had the time to install this on the other machines. The first step then get the children to go through the process of installing filezilla (minus root password). 

The next step was to figure out how to give filezilla the phone number of the computer. We did this and then entered additional data like the login and password (the information they need to log into machines).

The first try did not work and said that there was no response. I realized that having turned on the ports once the previous day was not enough and I turned it on again. 

Then was the issue of getting the passwd exactly right. This proved a little tough as it needed to be verbatim and the approximations children make to instructions of the teachers simply did not work and voila they were in.

The children seemed quite excited that they could transfer files between machines and one of them even looked up at the big monitor (connected to the pseudo server) expecting a visible reaction from the machine having transferred his file.

For closure of this experiment I went ahead and let each group of children who transferred files to present some of their work on the big screen to reward their work and prove to them that the files actually did get transferred.

Of course, we will move to a more permanent solution of mounting a drive on all the machines, but it was fun to enjoy the journey and not only the destination.