Lemon juice is acidic and weakens paper. When paper
is heated, the remaining acid turns the writing brown
before discoloring the paper.
Difficulty: Easy
Time Required: A Few Minutes
Here's How:
Tips:
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1. Squeeze lemons to
obtain their juice or
obtain bottled lemon
juice.
2. Use the juice as 'ink'
by applying it to a
stick or paintbrush
and writing on paper.
3. Allow the paper to
dry.
4. When you are ready to
read your invisible
message, hold the
paper up to sunlight,
a lightbulb
(recommended), or
other heat source.
5. The heat will cause
the writing to darken
to a pale brown, so
your message can now be read.
6. Another way to read the message is to put salt on
the drying 'ink'. After a minute, wipe the salt off
and color over the paper with a wax crayon to
reveal the message.
1. Experiment with other juices. White wine, orange
juice, vinegar, and apple juice all work well, too.
2. A cotton swab makes an excellent disposable
'paintbrush'.
3. The writing turns brown because the weakened
paper burns before the rest of the paper. Be careful
not to overdo your heating and ignite the paper!
Lemon or Lemon Juice
Sunlight or Heat Source
Paper
Paintbrush or Stick
is heated, the remaining acid turns the writing brown
before discoloring the paper.
Difficulty: Easy
Time Required: A Few Minutes
Here's How:
Tips:
What You Need
Topics
More From Chemistry
More From About .com
TOP
©2014 About.com.
All rights reserved.
Switch to Desktop Site
Menu
Chemistry
1. Squeeze lemons to
obtain their juice or
obtain bottled lemon
juice.
2. Use the juice as 'ink'
by applying it to a
stick or paintbrush
and writing on paper.
3. Allow the paper to
dry.
4. When you are ready to
read your invisible
message, hold the
paper up to sunlight,
a lightbulb
(recommended), or
other heat source.
5. The heat will cause
the writing to darken
to a pale brown, so
your message can now be read.
6. Another way to read the message is to put salt on
the drying 'ink'. After a minute, wipe the salt off
and color over the paper with a wax crayon to
reveal the message.
1. Experiment with other juices. White wine, orange
juice, vinegar, and apple juice all work well, too.
2. A cotton swab makes an excellent disposable
'paintbrush'.
3. The writing turns brown because the weakened
paper burns before the rest of the paper. Be careful
not to overdo your heating and ignite the paper!
Lemon or Lemon Juice
Sunlight or Heat Source
Paper
Paintbrush or Stick