Comments on: Science Fair Challenge – $50 Prize https://pennyportrait.com/2018/11/01/science-fair-challenge-50-prize/ Create a portrait of Abe Lincoln from your own pennies! Tue, 20 Jan 2026 02:47:43 +0000 hourly 1 https://wordpress.org/?v=6.9.4 By: maurymccoy https://pennyportrait.com/2018/11/01/science-fair-challenge-50-prize/#comment-25987 Thu, 21 Jan 2021 16:07:26 +0000 https://pennyportrait.com/?p=745#comment-25987 In reply to Roberto Ribeiro Aragon.

I wonder if there is a way to darken the pennies without scratching the surface of them? Excited to experiment though. I’ve never thought about loading up a solution with Cu ions… Though I think it is the Oxygen that actually makes the outside dark. I should have paid more attention in Chemistry!

]]> By: maurymccoy https://pennyportrait.com/2018/11/01/science-fair-challenge-50-prize/#comment-25986 Thu, 21 Jan 2021 15:40:41 +0000 https://pennyportrait.com/?p=745#comment-25986 In reply to Roberto Ribeiro Aragon.

Holy cow, you might be onto something here. I’ve never tried a chemical reaction that releases more copper into the solution to make pennies darker. Looks like I’ve got some experimenting to do to see if this could work for everyday folks who want to make a Penny Portrait. Exciting! I’ll let you know if I can get it to work.

]]> By: Roberto Ribeiro Aragon https://pennyportrait.com/2018/11/01/science-fair-challenge-50-prize/#comment-25984 Thu, 21 Jan 2021 13:38:44 +0000 https://pennyportrait.com/?p=745#comment-25984 maybe that will solve the problem
http://nobel.scas.bcit.ca/wiki/index.php/Penny_reactions

]]> By: maurymccoy https://pennyportrait.com/2018/11/01/science-fair-challenge-50-prize/#comment-24262 Mon, 19 Oct 2020 12:56:36 +0000 https://pennyportrait.com/?p=745#comment-24262 In reply to Steven Martinez.

I’ve actually tried this. It tends to make them BLACK, as in jet black. They don’t look natural.

]]> By: Steven Martinez https://pennyportrait.com/2018/11/01/science-fair-challenge-50-prize/#comment-24259 Mon, 19 Oct 2020 06:30:27 +0000 https://pennyportrait.com/?p=745#comment-24259 Liver of sulfur.

]]> By: maurymccoy https://pennyportrait.com/2018/11/01/science-fair-challenge-50-prize/#comment-12710 Tue, 03 Dec 2019 16:49:56 +0000 https://pennyportrait.com/?p=745#comment-12710 In reply to Chris Jenks.

Interesting… Off to find some hydrogen peroxide! (I have some sodium percarbonate here, so that might work as well…)

]]> By: Chris Jenks https://pennyportrait.com/2018/11/01/science-fair-challenge-50-prize/#comment-12606 Mon, 02 Dec 2019 22:35:56 +0000 https://pennyportrait.com/?p=745#comment-12606 Pennies darken over time due to reaction of copper with oxygen in the air. Then they can become green due to further reaction with carbon dioxide. Dark pennies become shiny again when treated with acid because the dark copper oxide reacts with acid to make a copper salt, which can then dissolve off. So treatment with base is not likely to help. A few ideas I would like to suggest as starting points for a student would be to try heating pennies for an extended period to help then react with oxygen, or perhaps heating them in hydrogen peroxide.

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