Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 11 replies
  • Subscribers 9 subscribers
  • Views 433 views
  • Users 0 members are here
Options
You may also be interested in
This discussion is locked.
You cannot post a reply to this discussion. If you have a question start a new discussion

Interesting problem ... basic engineering solution

gkenyon
So, today's engineering problem goes like this.


Someone in our family is dying their hair. The chemical (probably a Chromate-based hair dye) must be mixed with 180 ml of water at between 40 and 50 °C - if the temperature is too low, mixing is very difficult, too high and the compound breaks down, and perhaps you might not get the hair colour you need.


Simples ... except we have no thermometer.


How was this quick and easy to resolve?


Parents
  • 0
    Ah wet film - I was trying to explain it to my kids and getting blank looks of the 'why would anyone do that ?' kind.

    (to be fair most of what I did was black and white for PCB artworks, so large sheets of fine grain slow film, and red light safe, not photos to print - mostly I trusted that to the chemists shop in town  - i suspect the fact you can see it develop makes the temperature thing less critical for red light safe film.)

    Then we talked through the steps to make an IC,  and how many levels of photo-resist , masking, re-alignment and exposure that involves -  wet photography of a kind is actually very much alive and well in the age of the 'chip, its just got smaller, and in some cases the 'light' has gone very short wavelength  .
Reply
  • 0
    Ah wet film - I was trying to explain it to my kids and getting blank looks of the 'why would anyone do that ?' kind.

    (to be fair most of what I did was black and white for PCB artworks, so large sheets of fine grain slow film, and red light safe, not photos to print - mostly I trusted that to the chemists shop in town  - i suspect the fact you can see it develop makes the temperature thing less critical for red light safe film.)

    Then we talked through the steps to make an IC,  and how many levels of photo-resist , masking, re-alignment and exposure that involves -  wet photography of a kind is actually very much alive and well in the age of the 'chip, its just got smaller, and in some cases the 'light' has gone very short wavelength  .
Children
No Data

Join us to get the best from IET EngX.

Joining EngX lets you personalise your experience so you stay up to date on the topics that interest you, plus you’ll be able to make connections who are looking to collaborate, exchange ideas and more.

Join us Not now

Community Rules & Guidelines