f/0.38 camera lens made with oil immersion microscope objective

https://invidious.privacyredirect.com/watch?v=DQv0nlGsW-s

I removed the protective glass from a CMOS image sensor, and used optical immersion oil to couple the bare image sensor to a 40X NA=1.3 microscope objective.
f/0.7 Zeiss lens described in amazing detail: http://www.marcocavina.com/omaggio_a_kubrick.htm 
Fake f/0.33 Zeiss lens: https://petapixel.com/2013/08/06/carl-zeiss-super-q-gigantar-40mm-f0-33-the-fastest-lens-ever-made/ 
Camera and sensor that I used: https://www.ids-imaging.us/store_us/products/cameras/ui-5584le-rev-1-2.html https://www.onsemi.com/products/sensors/image-sensors/mt9p006?pdf= 
Conversion from f/# to NA: https://www.eckop.com/resources/optics/numerical-aperture-and-f-number/ 
More discussion about the f/#: https://wp.optics.arizona.edu/jpalmer/wp-content/uploads/sites/65/2018/11/The-f-stops-here.pdf 
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Mutarotation: a sugar that spontaneously changes from sweet to bitter

https://invidious.privacyredirect.com/watch?v=kiuXasyB3L0

Simple sugars can exist in multiple molecular conformations, some of which have different tastes and optical properties.

Steve Mould's video on optical rotation: https://invidious.privacyredirect.com/watch?v=975r9a7FMqc

Reaction's video on Mexican Coke: https://invidious.privacyredirect.com/watch?v=NY66qpMFOYo

Research paper describing enzymatic synthesis of L-glucose: https://nopr.niscpr.res.in/bitstream/123456789/17714/1/JSIR%2061%285%29%20361-365.pdf

D-mannose on Amazon: https://www.amazon.com/Micro-Ingredients-Mannose-Supplement-Soluble/dp/B01L2TFP1Q

My crystals were almost entirely the sweet form, but it is possible that your bag may have the bitter-tasting form to begin with.

D-fructose on Amazon: https://www.amazon.com/Fructose-Fruit-Sugar-16-ZIN/dp/B07DXVSGJT

D-glucose, also known as dextrose, also known as "corn sugar", can be found on Amazon, or beer homebrewing stores.

https://www.patreon.com/c/AppliedScience

Micronics SLS nylon 3D printer makes electronic circuits

https://invidious.privacyredirect.com/watch?v=UIqhpxul_og

A new desktop SLS nylon 3D printer can make printed electronic circuits with the addition of a powdered catalyst and electroless copper plating bath. The printer is available here: https://www.kickstarter.com/projects/micronics3d/micron-a-desktop-sls-3d-printer
Applied Science video on SLA printed circuits: https://invidious.privacyredirect.com/watch?v=Z228xymQYho
Favorite copper plating bath recipe: Heat 250ml deionized water to 60*C in a 300ml beaker, stirring at 350 RPM Add 2.5g CuSO4*5H2O, wait until dissolved Add 4.6g EDTA disodium dihydrate, wait until dissolved Add 0.84ml of 1% Triton-X 100 solution in water Dissolve 5.8g NaOH in 30ml DI water, stir until clear, then add to bath Add 4ml Formaldehyde (37% HCHO) Lower stirring to 100 RPM and...

OpenQuantum’s DIY Open-Source Magneto-Optical Atomic Trap

Last weekend, Max Shirokawa Aalto presented his OpenQuantum project at the 2023 Hackaday Superconference.  OpenQuantum’s platform is a fully open-source magneto-optical trap which can be used to collect, control, and manipulate ultracold rubidium atoms. The design is fully open-source, and includes all the CAD files, machining instructions, electronics schematics, PCB files, firmware, and software necessary […]

In Memoriam: Robert (Bob) Iannini (1938-2023)

I recently learned the saddening news of the passing of Robert (Bob) Iannini on April 3, 2023, just shy of his 85th birthday. Bob, an extraordinary inventor, celebrated book author, and the mastermind behind “Information Unlimited,” succumbed to pneumonia, leaving a void in the world of amateur science and electronics. From my high school days, […]

Photosynthesis photography: Making images with living plant leaves

https://invidious.privacyredirect.com/watch?v=-qETedzsFIE

How to make photographs using plant leaves: the technique, examples, f/0.5 camera lens construction, and tips & tricks that I learned along the way.

Inspiration for this project came from a 1970's video made by The Royal Institution: https://invidious.privacyredirect.com/watch?v=l2JTiAASdyw

Starch formation refs: https://www.journals.uchicago.edu/doi/pdf/10.1086/329993

https://www.ars.usda.gov/ARSUserFiles/50820500/GPRG/2022PulicationsandSummaries/2022_Photosynthetic%20responses%20of%20greenhouse%20ornamentals%20to%20interaction%20of%20irradiance%20CO2%20and%20temperature.pdf

Video describing inkjet printed photomasks: https://invidious.privacyredirect.com/watch?v=bR9EN3kUlfg?si=k9RU6EwM5-pKx2tr&t=643

A different technique to make leaf prints: https://www.alternativephotography.com/chlorophyll-prints/

Video from Alpha Phoenix on making photos with cyanotype: https://invidious.privacyredirect.com/watch?v=ewQQX3fxQKk&t=85s

Ray optics simulator: https://phydemo.app/ray-optics/

Giant tweezers: https://www.amazon.com/Stainless-Tweezers-Anti-slip-Aquascape-Maintenance/dp/B07LDLWJMM/

Anhydrous ethanol: https://www.extractohol.net/1gal-200-proof-pure-food-grade-ethyl-alcohol

Hanging basket geranium plant: https://www.lowes.com/pd/2-Gallon-Multicolor-Geranium-in-Hanging-Basket-L5450/1000151713

Methanol toxicity: https://en.wikipedia.org/wiki/Methanol_toxicity https://sci-hub.se/https://doi.org/10.1016/j.ccc.2012.07.002  Skin absorption in a quantity high enough to be a problem is rare, according to this.

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Measuring the amount of lead (Pb) consumed when drinking from lead crystal glassware. Is it safe?

https://invidious.privacyredirect.com/watch?v=-cAB5FG4bXI

I show a "DIY" chemical color-based method to determine the amount of lead in water, and then use the method to measure the amount of lead extracted from various types of lead crystal glassware.
Skip to 27:05 to see the detailed results 
Code, analysis, raw data, more references: https://github.com/benkrasnow/LeadCrystal 
Average daily lead consumption: 50ug in early 1980s, about 2/3 of this came from food and water https://openlibrary.org/works/OL18340799W/Food_contamination_from_environmental_sources?edition=unset0000unse_z0t6 
The FDA established a maximum daily intake for Pb called the Interim Reference Level (IRL). The IRL for children and adults is 3 μg/day and 12.5 μg/day, respectively. In 2022, FDA tightened its Interim Reference Levels (IRLs) for...

Multi-layer reactive foil: no fuel, no oxygen, tons of heat

https://invidious.privacyredirect.com/watch?v=eGj4jfYhDxA

This unusual sheet metal is made of hundreds of nano scale layers of aluminum and nickel. A spark initiates a self-propagating reaction that creates NiAl compound, and lots of heat! This material is used to solder items so fast that the base material doesn't have time to draw heat away from the joint. The technical data sheet indicates that this process is fluxless, and I suspect trying to include flux would cause rapid gas expansion that would blow the solder joint apart. I'm not sure how the solder wets the surface without flux. https://sci-hub.se/10.1063/1.1629390 https://en.wikipedia.org/wiki/Nickel_aluminide https://www.indium.com/products/nanofoil/#documents https://www.patreon.com/AppliedScience

Temperature-sensing RFID tag in magnetic stir bar

https://invidious.privacyredirect.com/watch?v=nh1SIfipQs4

I describe an old project in which a few friends and I designed an RFID tag that fits into a magnetic stir bar and measures temperature wirelessly.  We decided to open-source the project, and you can see the PCB design and tag firmware at the github repo below.  I don't think I have the firmware for the base station, unfortunately.

https://www.ti.com/product/TMS37157

https://www.digikey.com/en/products/detail/texas-instruments/EZ430-TMS37157/2183733

https://github.com/benkrasnow/Temperature_sensing_stirbar

https://www.patreon.com/AppliedScience

Identify chemicals with radio frequencies - Nuclear Quadrupole Resonance (MRI without magnets)

https://invidious.privacyredirect.com/watch?v=JO_EHceV9sk

How to build and test an NQR spectrometer, which is similar to MRI, but uses no magnets.  NQR frequencies are unique among all tested compounds, so detecting a resonance indicates a near certainty that a specific chemical is present.

Tektronix 2-series oscilloscope: https://www.tek.com/en/products/oscilloscopes/2-series-mso Video capture was done via VNC client

Zeeman effect shifting optical spectral lines: https://invidious.privacyredirect.com/watch?v=JV4Fk3VNZqs?t=74

Atomic clock calibration using Zeeman effect: https://invidious.privacyredirect.com/watch?v=xTy1kY_wtsY

W2AEW's RF tutorial on quarter wave transmission lines: https://invidious.privacyredirect.com/watch?v=A1BAq0KxIdc

Water deflected by electric field: https://invidious.privacyredirect.com/watch?v=NjLJ77IuBdM?t=468

Litz wire only helpful between 50KHz and 1.5MHz - https://invidious.privacyredirect.com/watch?v=FUCRB9UdfUg?t=2010

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Q/A

Why use vacuum variable capacitors? The parallel LC circuit develops well over 1000...