Extending Grabber


Extending Grabber


Explore simple machines and scissor mechanisms by creating an extending grabber. This lesson can be used as a precursor to a hydraulics lesson.


Presentation Type



Hinge: Something that connects two objects and lets them rotate.

Pivot: The pin on which a mechanism turns

Force: The push or pull on an object

Scissor Mechanism: Two straight bars that are connected to each other at their intermediate points by a joint

Lever: Rigid bar resting on a pivot

Target Audience Minimum Age

Target Audience Maximum Age

Duration in Minutes

Event Type

In person, Activity Kit


As a result of participating in the program, participants will understand the mechanics of a simple hinge and how to manufacture one.

Life Skills

Career Fields

Tech Level

Consumable Costs

Per person:

2 milkshake straws (10 mm)- $0.12

9 craft sticks- $0.30

8 toothpicks $0.04

1 foot tape- $0.02

Optional “Finger” Materials:

Rubber Bands

Hot glue gun/sticks

Pipe cleaners

Testing Materials:

Cup or bowl

Pom poms or beads

Materials/Costs in $



Prep Time in Minutes

Prep Details

Optional: Precut the straws into 2 inch pieces

Evaluation Method

After building their grabber and designing the "fingers," students may test their grabbers by picking up small objects (like pom poms) and moving them into a cup or bowl.


Creating the Scissor Mechanisms

Cut straws into 8 pieces 2" long each

Create 4 levers by inserting craft sticks into each end of 4 pieces of straw

Reinforce the straws by taping a toothpick to the side of each

Overlap two levers at the straws and push a toothpick through the straws to create a scissor mechanism (looks like an X.) Add two more pieces of straw to the top of the X.

Repeat with the other levers.

Turn the scissor mechanisms (Xs) so the top straws are facing each other. Use toothpicks to connect the top straws to each other. Repeat with the bottom straws.

Designing the "Fingers"

Students may now design their "fingers" for grabbing using any extra materials. I recommend first attaching half of your 9th craft stick to each end using  hot glue, then adding on "grippers" of your choice. See the photo tutorial or the instructable for ideas. 

Files & Other Media