TOOLS OF THE DETECTIVE TRADE:

MAGNIFYING GLASS

 

OK.  So you are a detective.  You have found a notebook lying on a park bench.  The pages are blank – invisible writing of secret information maybe?  A spy you have been tracking might have left it for his contact.  You can see faint fingerprints on it.  Were they made by the spy?  Are any of them useable for identification purposes?

 

You don’t happen to have your trusty magnifying glass with you, so you quickly make one using an empty soda bottle, a penknife, and a little water.

 

You take a closer look at those fingerprints.  Aha.  You were right!  The notebook does belong to the spy.  You pick it up and take it back to the lab to reveal the hidden message.  Job well done.

 

You can make a makeshift magnifier yourself at home.  Here’s how.

 

This doable needs:

 

• 1 clear, clean plastic disposable bottle (ours was 64 ounces)

• Sharpie pen

• Scissors or utility knife

• Water

 

Helps to also have: 

 

• 3” diameter tin can or drinking glass

• Pencil

• Piece of paper

• Two small blocks (we used Duplo pieces) to prop the makeshift magnifier on

 

Steps:

 

1.  Draw a circle on the piece of paper using either the tin can or the drinking glass turned upside down on the paper to guide you.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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2.  Cut out the paper circle, and then use it to trace a circle on the upper edge of the plastic bottle.

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3.  Then cut out the circle on the plastic bottle.  It is hard to get started – an adult might need to help by cutting through the bottle first using a utility knife.  Be careful with the scissors and utility knife! 

 

4.  Put a little water in the disc from the plastic bottle, and hold it over the print or text you want to enlarge.  (We propped ours on two Duplo blocks to keep it steady.)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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5.  Doesn’t the fingerprint look larger and easier to see?