This Brownie forensics evening will give the Brownies a chance to develop their deductive skills as they work together in teams to solve a crime in your meeting place. It can be used towards the Brownie Science Investigator badge.
 

Setting the Scene

 
Before the start of the meeting, hide something that the girls would usually expect to see at Brownies, such as the owl or toadstool.

Start the meeting as normal, and see if anyone spots that the item is missing.

Once it is missed, suggest that it must have been taken by one of the leaders or young leaders. They were the only ones who had the opportunity. Explain that they must look for clues and carry out some forensic tests to help them decide whodunnit.

Set up the following activities for the girls to try in their hunt for the thief…

 

Which Pen?

 

Equipment

  • Two similar coloured felt tip pens
  • Kitchen paper or coffee filter paper
  • A mug of water

 

Preparation

  1. Use one of the pens to create an example using the method below. The Brownies should use this to match against their test result

 

Instructions to the Brownies

Each pen uses a different mix of dyes. If we separate the dyes we can see which pen was used. This is a technique called Ink Chromatology.

  1. Cut a strip of paper towel
  2. Draw a dot with the pen you want to test
  3. Place the strip of paper towel in a glass of water with the dot just above the water
  4. As the water soaks up through the paper you will see a distinctive pattern for that pen. Compare this with an example from the scene of the crime. If it does not match you will need to test another pen

 

How Tall?

 

Equipment

  • A piece of paper
  • A tape measure
  • A calculator (optional)

 

Preparation

  1. Rub the sole of one leader’s shoe in some dirt and use it to create a footprint. If it is dry you could make the footprint in a flowerbed outside for the Brownies to discover
     

    Instructions for the Brownies

    An adult’s left foot will measure about 15% of their height. This can help us to estimate how tall an unknown person might be just from their footprint.

    1. Measure the footprint left at the scene of the crime in centimetres
    2. Multiply the length by 2
    3. Divide the result by 3
    4. Multiply the result by 10
    5. Now measure the height of each of your suspects in centimetres. Who is closest to that height?

    What else could you tell from the footprint that might incriminate your suspect?

 

Fingerprinting

 

Equipment

  • Moisturiser
  • Cocoa powder
  • A sieve or tea strainer
  • Selotape
  • Ink stamp

 

Preparation

  1. Lightly rub moisturiser into one finger then whilst the finger is still moist press firmly on a smooth surface (we used the back of a spoon)
  2. Leave the spoon somewhere for the Brownies to discover during their investigation
  3. Use the ink stamp an a piece of paper to create a set of reference finger prints of each suspect.

 

Instructions for the Brownies

What objects might have been touched by the person who stole the owl? Look closely for finger prints.

  1. Use the cocoa powder and brush to dust lightly for fingerprints.
  2. When you find one, carefully put a piece of selotape over it and peel it up gently.
  3. Stick the piece of selotape onto a piece of white paper and examine it closely
  4. Compare it to your suspects’ fingerprints

 

Handwriting Test

 

Equipment

  • A piece of paper

 

Preparation

  1. Get your culprit to write a short shopping list on a scrap of paper
  2. Leave the shopping list somewhere for the girls to find

 

Instructions for the Brownies

A scrap of paper was found near the scene of the crime. It may have been dropped accidentally by whoever took the toadstool.

  1. Look carefully at the handwriting. What are the most distinctive features?
  2. Trick your suspects into giving you a sample of their handwriting. Think about what words you could get them to write that would help you decide if their writing matches the note. They shouldn’t suspect you will be testing their writing. If they do, they might write differently!
  3. Compare their writing to the note. Who do you think wrote it?

 

Interview Technique

 

Equipment

None!
 

Preparation

None!
 

Instructions for the Brownies

  1. Interview each of our suspects for one minute each. Get as much information out of them as you can.
  2. Who do you believe most? Did they give you any other clues?

Conclusion

Once all the tests have been carried out, each group should decide who they are going to accuse and why.

Ask each group to make their accusations and justify their accusation based on the evidence. You might want to take a vote on the most likely culprit.

When confronted, the suspect should confess and reveal the location of the ‘stolen’ item.