Status Update: Solar Cooker

Here’s what I’ve been up to.

  1. Researching can-openers


  2. Cutting cans – lots of them


  3. Flattening the sheets or trying to. The ten inch can needed more work. I will need to extend the tin panels further by at least five inches on one side to make use of angular sunlight.


4. This is what my collection looks like now

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5. An unanticipated problem – the broken umbrella is not broken enough. The metal rod is at the focal point and needs to be removed. This is proving to be more difficult than I had anticipated and I gave up trying. The new plan – make a sheet of reflective metal from soda cans and duct tape and cut it in the shape of an umbrella.

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6. The plan for the third cooker had to be changed as well. Instead of a trough like cooker I will now make one out of a shallow cardboard box and mirrors.

Fingers crossed!


Final Project – Possibilities

I want to make a solar cooker that works really well in the summer and hopefully in winter as well. I have tried to use as many “usable trash” components in my project idea but I would also like to use sheets of metal to make the cooker from scratch. I  don’t have access or the skills required to cut and fold metal and this is the biggest limitation.

I have included doodles from my notes to explain the three possible design ideas. THe overarching idea is to use reflection of solar radiation from as many angles possible to heat a metal sheet which heats up, transfers the heat to materials being cooked. I think of it as trapping heat. When the food is almost cooked I would like to cover the cooker to retain moisture in food as well as use energy efficiently.WP_20151027_09_53_03_Pro1WP_20151027_09_54_53_Pro

The simplest design I have uses a large tin can. The sides of the can will be cut along its length and bent outwards to reflect radiation. The upper cover of the can can be cut to size to use as a lid.


The next design is a bit quirky and uses the frame of a broken umbrella. I intend to place metal sheets or other reflective surfaces along the inner surface of the umbrella. The doodle explains the design better. When finished it will look like flower. This setup is only the arrangement of the reflective surface. The actual cooking can be done in a stainless steel plate with a border of at least an inch. This plate needs to be placed inside the reflective surface setup.


The third design possibility is the one that I shared in class the other day. For this a food grade metal sheet needs to be bent to form an angle between 45 and 60 degrees. Since I intend to cook food  in it there needs to a panel system built around the sides of the v. When food is half cooked the cooker can be sealed from both sides and the top. I will definitely need to use tools and acquire basic fluency with metal work. WP_20151027_09_53_15_Pro

Final Project Ideas

Usable Trash Repurposing old toys and toy components
Beer bottle hydroponics system

Beer bottle + LED bulb

Instant papier mache
Light saber
Discarded yo-yo used in skirt to light up with a spin
Block printing system
Reflective surfaces art
DIY wagon
Find new purpose for a tooth brush motor
Christmas trees that are not trees
DIY loom
Rainbow maker
Holiday décor
Repurpose plastic bags
Soda can heating system
DIY Bio Vermicomposting kit
DNA extraction kit
Bacterial culture kit
Ginger ale
Fruit ripening system
Art Art machines
Graded thermochromics
LED toys to blinking capes and costumes
Laptop bag with Wi-Fi detector
Seat that lights up when you sit on it
Glow stick creations
Culture Recreate traditional baby carrying systems
Find out, through interviews, what happens to old toys, gadgets, and “stuff”
Interview artists-makers-scientists about their transitions across the interface

In the spirit of sustainability preliminary notes were taken on a restaurant menu.

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Milking Ideas

Milk is a staple in my kitchen and I take its benefits and uses for granted. For this project I have maintained a focus on milk by making cottage cheese and clarified butter at home.

Cottage cheese

I have been making cheese at home for many years now. The milk was fresh from the farm and had very high fat and protein content. I decided to try it with grocery store bought milk and note any differences  in the cheese making process as well as taste. The steps are described through photographs.

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Once milk came to a boil I added about two tablespoons of vinegar to it. Ideally, I would use two litres of milk in a heavy pan and heat it over a very low flame. Milk would reach boiling point in an hour. The surface would have a very thick layer of fats which I would separate and refrigerate for making clarified butter. The cheese was strained through a very soft muslin and refrigerated. The cheese I made was less creamy but tasted quite good. I would give it six out of ten for flavour and texture.

Clarified Butter

As I said, the thick top layer of milk fat is used for making clarified butter. It is a lengthy and messy process but the flavour makes the effort worthwhile. For the project I used unsalted butter. My argument was that it is called clarified butter and so, there has to be a way to make it from regular butter. The following are the steps.

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A small cube of butter was added to a heavy vessel and heated on very low flame. Once the butter came to a boil, light brown froth could be seen at the surface. The brown froth also had some milk solids in it and had to be strained. The resulting clarified butter was dark golden colored and smelled different from the butter I made at home. It tastes and smells good, but in a different way. This could be because of the used butter, and the small portion used.

This is a good way to visualize the number of components in milk – proteins, SNP (Solids Not Protein) and fat.

A Bacterial Biomarker of pH

Fermented food items are a staple in many cultures. They are popular for great taste and health benefits. The only disappointment is that fermentation is a complex cellular process and replicating it in a kitchen requires expertise. Keeping our recent enthusiasm in food science, I will discuss biomarkers in the fermentation of milk.

Fermentation of milk is the process in which Lactobacillus species convert lactose into lactic acid. This causes the pH of the milk to decrease. Casein, the protein component of milk coagulates in low pH environments. This seems easy and simple, except when things go wrong. Yogurt, for example is best made from a fresh culture of Lactobacillus not more than two days old. Once the culture gets older than that, the resulting yogurt tastes excessively sour and later, even bitter. When acid begins to accumulating in the yogurt, bacteria sense it as a sign of stress. Stress metabolism triggers a complex process that leads to sporulation – the bacterial equivalent of hibernation. Normal growth in such bacteria can be revived only when the conditions are favorable – plenty of sugar to feed on.

Sporulation can be identified with a microscope. Sporulating bacteria take up less stain and show encapsulated spores inside them.

lacto spores
Gram stained sporulating Lactobacillus
Gram stained Lactobacillus

Soil Concepts for the Young Scientist

Young scientists, also known as  children, make useful and pertinent observations regarding natural phenomenon. Their interaction with soil and sand is also more personal and regular than the kind of interactions that adults in urban areas have. Even with limitations like lack of open patches of dirt or uncultivated land, expectations of more structured play, children explore and draw relevant conclusions about soil systems. This infographic is meant to tie their conclusions together in a scientific manner to help them decide the quality of the soil they are interacting with. Questions about bad smelling soil and its implications can be answered with the help  of this infographic.

For older enthusiasts capable of growing microorganisms in a petri dish, I plan to create a similar infographic based on a shape sorter theme. Microorganisms growing in colonies in a petri dish show unique physical and chemical properties that can be used to identify them.

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Measuring UV Exposure when you’re NOT out in the Sun

We all worry about UV exposure when we are at the beach or spending unusually long hours outside in the sun. What we don’t worry about is the ways we can still expose ourselves to UV when we are NOT out in the sun, or when we think we are protected from UV.

UV exposure is cumulative and it is not possible to measure the extent of exposure with a UV measuring system.

The idea for this assignment was to use the Sparkfun Arduino SI1145 visible-UV-IR sensor for this purpose.

The first roadblock was the complete lack of any coding experience. I have tweaked Scratch and R to suit project needs but never “written” code from scratch and was very enthusiastic and hopeful about this assignment and didn’t want to limit the project to a blinking LED. The Windows interface posed an additional initial challenge but Stacey and Jennifer saved the day!

This is what the initial setup looked like


The final code

The output – indoor

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The output – outdoor

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It will be interesting to take the system on a drive with me even on a cloudy day, or even check artificial light sources for UV radiation

How Tempe Copes with Heat

To find out how people cope with the heat in Arizona I went about my neighborhood and looked into trash cans and a few other more obvious places.


This is what I found.

Hydration matters. I found a number of large styrofoam glasses of soda in every trashcan I looked into. I even saw one balanced on the dashboard of a vehicle. Chilled beer was the second most popular drink, Gatorade and good old water came in third.

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These photographs were captured at different times of the day. The parking lot had discarded soda cups, water bottles, and water bottles at seven in the morning. The community trash cans were photographed late in the evening and the bus stops trash cans were photographed around noon on two separate days.

Sunglasses and hats/caps offer much needed physical protection from heat. I found hats and caps to be popular with older citizens and children; sunglasses are popular with all age groups. Flip-flops are popular too.

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The pool is the go-to place in the evenings and on weekends, even when it was cloudy for a few days.

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Misting systems were operating till late in the evening and offered respite to patrons. Earlier in the day people chose to sit inside the restaurant and enjoy the air conditioning but in the evening families enjoyed the cool mist while having dinner. IKEA’s misting system worked all day till seven in the evening.


The two most popular ways to cope with heat: fluids, preferable chilled. and shade.

Heat themed silkscreen printing

Light bulbs are known to generate heat enough to burn human skin. LEDs are more energy efficient. I wanted to use thermochromics ink to compare energy efficiency of a string of LED lights and an LED bulb.

My silk pattern is very basic, two triangles in a row. Two rows inverted and overlapped look similar to strands of DNA in the middle of being replicated. My intention was to place the string of LEDs at the intersection of the two strands to make the two strands appear physically separated from each other.



The silk screen preparation was quite simple but the print turned out sloppy. I made multiple copies of the print, had to wash the screen midway and dry it before I could use it again. This is how it looked on thick A4 paper.


I traced the border of the pattern to hide the messy edges and used a pencil tip to puncture the paper at designated places so that I could insert LEDs into them.

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One sheet had LEDs all over it and the other one had LEDs inserted right into the design tracing the paint. I checked the sheets after 15 minutes, 30 minutes, one hour and five hours. No change was observed in wither sheet after 15 minutes, after thirty minutes the sheet with LEDs inserted into the design had small circles around the LEDs where the dye was bleached.


After five hours the pattern was a lighter shade of gray. Once the pattern was exposed to heat from both LED string and a bulb the color was significantly bleached.


Priyanka, introduction

A DIY-er a heart, I DIY because I can even at times when I should not. The interface of science, art, craft, tinkering, and learning excites me, and I wish I could DIY a portable fMRI machine to visualize the effect of an idea on the human brain.

Some recent experiments I have enjoyed include:

  • Isolating plant DNA using cleaning reagents – a messy process not for the weak of heart.
  • Using markers to create spray paint – a very interesting art machine that destroys the marker.
  • A DIY hydroponics system in a beer bottle to encourage cut stems to grow roots.
  • My favorite DIY project till date is my daughter.

In my opinion glow-sticks are exceptionally powerful and accessible DIY/citizen science artifacts. Not only do they encourage experimentation through creation of “fun” stuff, they help people visualize the power of a chemical reaction. The physical snapping of a capsule inside a plastic casing enabling the mixing of two chemicals to release electrons which are then captured by a dye molecule to emit light. I find the humble glow stick to be elementary yet powerful science that can easily be used to generate interest and encourage participation in scientific exploration.

A glow-stick torch made of four green glowsticks covered with construction paper and secured with tape.
Glow-Stick eyewear for enhanced visibility


A more serious citizen science initiative is the EteRNA project that made it possible for all kinds of people to create unique 3D folded RNA molecules. Although participation in EteRNA requires access to a computer, given the esoteric nature of molecular biology, it is a great way to initiate interest and participation.

I am excited about the DIY Science class because it confirms my belief in the power of DIY in informal science education. I look forward to participating wholeheartedly in all the sessions and getting to know opinions about DIY science as well as the ways in which we practice science.