Wednesday, July 28, 2010

Got Invisible Ink?

E (age 5), and I were inspired by Jim Wiese's Spy Science: 40 Super Sleuthing, Code-Cracking Activities for Kids, to try our hand at some undercover art, today.

First, I gave her a piece of paper, a bowl of milk, and a q-tip.

She dipped the q-tip into the milk, and used it like a paint brush, to draw a picture of a weather girl (I think). Not wanting to be left out, I wrote a quick message on another sheet of paper, myself, and we left them to dry for a couple of hours.

When we returned to our papers, the milk had dried clear, if a little shiny. I thought my message was still too legible, so I crinkled my paper up, hoping it wouldn't ruin the "ink".

Then, we covered the papers with bits of graphite, by rubbing a pencil, on sandpaper, over the sheets.

We smoothed the graphite out with a napkin, and our drawings, magically, appeared.

Wiese suggests using whole milk, because it's the fat, the graphite sticks to. So, the higher the fat content, the better the experiment will work. We were happy with the success we had with 2%, though.

It even worked, for the most part, on my crumpled up paper, where the message had been rendered completely invisible.

It's great to be a homeschooler.


Christy Killoran said...

I think I remember making invisible ink with lemon juice once as a kid, but I'm not sure if that is really accurate - it was a long time ago!

I like the weather girl drawing.

Ticia said...

That works pretty well. We tried it with lemon juice a few months ago. I knew you could do it with milk, but didn't know the details of how. Now I do!

Natalie said...

Funny, we were just looking at invisible ink today too! :-)

Ours said to use lemon juice and you put the paper in the oven for a bit and the hidden pic/writing appears brown (when the juice burns slightly).

I used to have loads of fun with this as a kid, but like your tip to use Q-tips!

Sparklee said...

This looks so fun! I know what we're doing at our next scout meeting: invisible ink, What's in the Play-Do, and loop airplanes. Thanks for the great ideas!

Natalie PlanetSmarty said...

You do have great ideas! I didn't know this invisible ink method - we did lemon juice in school.