Guide - Simple Machines and Linkages

Explore creative inventions made from scissor linkages. Discover the design challenge of building and improving a small mechanical arm to pick up a weighted variety of objects. Start with making 2 pairs of scissors, then to combine to build a mini mechanical arm, learning about mechanical advantage. Make a small pyramid, also called a tetrahedron, to pick up.

Please note this resource was tailored for US schools and may require adjustments to suit UK schools.

🇬🇧 Teacher Notes

### Lesson Structure

When students go through this lesson in each section, the objectives they will learn are:

* **Imagine** – Learn about linkages arranged as scissors used in different inventions.
* **Build** – Combine levers into a mini mechanical arm to pick up a pyramid.

Teacher Notes

Overview and Objectives

Materials

#### Teachers: Preparing Your Students (15 min)

When students begin the lesson, they start in [Overview and Objectives](#overview-and-objectives), then transition to this [Preparation](#preparation) section. Presented in their view is a vocabulary list of terms and infographics illustrating concepts across STEAM domains throughout this entire lesson.

There are extra guides for preparing student readiness for their first engagement of new terms and content knowledge. Print or distribute the guide digitally. 

* Read through the vocabulary list. (5 minutes)
* Review the 6 simple machines. Download the optional asset and share to students. (10 minutes)

#### Vocabulary (5 minutes)

This is the list of vocabulary terms used throughout the lesson. They will be in **bold** and the definition listed throughout the different sections and in **Student Journal** asset. Students can always revisit the vocabulary definitions with media and questions in the lesson. (5 minutes)

#### Simple Machines and Linkages (10 minutes)

Review the 6 simple machines. There is an **optional** guide used as a printout or can be shared online to students before they engage this lesson. Each simple machine is designed to make work easier or more efficient and referenced in this lesson. Download the optional guide. (10 min)

Preparation

### Linkages to Machines

* Humans using tools rely on their mechanical advantage to perform tasks beyond physical capabilities.
* The mechanical arm is made of 4 **links** joined together with rotational joints forming a **linkage**. The particular links composed together in the mini mechanical arm are called scissor **linkages**.
* The 2 moving **pivot points** in the center of the arm moves away from its original position for the arm to stretch and grab. If one of these **pivot points** were fixed, the **links** of the arm still moves, with the **pivot joint** remaining in its original place. If both **pivot points** are fixed, it becomes a structure.

For tasks including reaching or crouching, the mechanical arm can be useful for picking up a dropped object or grabbing from the top of a shelf. The collapsible bonus of the arm makes it easy to store and use on the go.

Imagine

Build a pyramid (tetrahedron)

Build moving joints and beams then combine to make 2 types of scissors

Make claws and attach to one of the scissors for gripping

Connect both pairs of scissors to become a mini mechanical arm

Pick up the pyramid then try other objects

Combine the pyramid and mini mechanical arm by removing pieces

Test the modified arm to grab more objects

Test the arm again while observing closely at how the mechanical design works

Build

STEAM Classroom

United States

Define a simple design problem reflecting a need or a want that includes specified criteria for success and constraints on materials, time, or cost.

NGSS

3-5-ETS1-1

Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem.

3-5-ETS1-2

Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved.

3-5-ETS1-3

Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.

MS-ETS1-1

Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.

MS-ETS1-2

Students develop, test and refine prototypes as part of a cyclical design process.

ISTE Students

1.4.c Innovative Designer

Students communicate complex ideas clearly and effectively by creating or using a variety of digital objects such as visualizations, models or simulations.

Intro: Scissor Linkages

Overview and Objectives

Lesson Structure

Overview