What Makes a Trap a Trap?

What do you think you know about traps right now?

Take a moment to answer the following questions:

• What is a trap?
• What is the purpose of a trap?
• What makes a trap successful?

Now it is time to CONSTRUCT a trap!

For this activity you will need:

• An empty plastic soda bottle - quart, liter, or 2 liter size
• Scissors
• A small marble (or tin foil to make a small ball)
• Scotch tape

Step 1) Prepare the bottle

• Be sure your bottle is rinsed out.
• Remove the label from the bottle as best you can.
• You do not need the cap.

Step 2) Cut the bottle

• Using scissors, cut the top 1/3 off the bottle so that you end up with 2 pieces as shown in the photo above. You may need to use a sharp tool, like a knife, to create a slit in the bottle so that you can insert your scissors. Definitely ask for help! Cut all the way around so that you end up with the 2 pieces as shown above.

Step 3) Construct a trap

• Insert the top half of the bottle into the lower half.
• Be sure you insert the narrowest part of the top half of the bottle into the lower half so that the mouth of the bottle is inside.
• Use some tape to keep the pieces together.
• Congratulations, you just made a trap!

Now it is time to try it out:

See if you can get the marble inside the trap and then try to remove it without taking the trap apart.

• Could you do it? 
• Could you get the marble out? 
• Was it easier to get the marble in or out? 
• What makes it easier or harder to get it in or get it out?

Explanation:

You made a small FUNNEL TRAP which can be used to catch small fish. It is called a "funnel trap" because the entrance to the trap is a funnel.  A funnel is a tube that is wide at the top and narrow at the bottom. The wide opening at the top makes it easier for fish to get inside the trap, and the narrow opening makes it hard for the fish to get out of the trap.

A successful trap should do two things:

1. It should provide an easy way to get into the trap.
2. It should be hard to get out of the trap.

What do you know about traps now?

Let's revisit the following questions:

• What is a trap? (An object that is used to catch something alive)
• What is the purpose of a trap? (To catch something and hold it)
• What makes a trap successful? (Easy to get in but hard to get out)

Optional Activity: Look up “water bottle fish trap” on YouTube to see this trap catching fish.