Guide - Simple Machines and Linkages

Discover the four-bar linkage, a mechanism made of links and pivot joints, and its applications in engineering. With the linkage, construct a moving giraffe head, reaching upward for the leaves of an acacia tree.

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** – Linking knowledge about linkages and scissors with links to machines and animals.
* **Build** – Combine links to animate a giraffe puppet.

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 is an extra guide 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 listed throughout the different sections. Students can always revisit the vocabulary definitions with media and questions in the lesson. (5 minutes)

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

Review the simple machines and linkages. 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

### Advantage of the Four-Bar

A **four-bar linkage** is a series of links that are joined in a closed set.

* It is composed of 4 **links**, also called bars, which join together forms **linkages.**

The **four-bar linkage** is the most basic type of closed chain linkage.

* The first **linkage** is fixed, or attached to the ground, and is the **pivot point** for the other **linkages**.
* One **linkage** called a crank **linkage**, rotates around the fixed **linkages**.
* The other two remaining **linkages** move in connection to the crank **linkage** and fixed **linkage**.
* They are called the coupler and rocker arm.

The **four-bar linkage** can also have many variations, which make it helpful for prototyping designs and engineering.

* The motion of pedaling a bicycle is a classic example of a **four-bar linkage**.
* Internal combustion engines, or gasoline engines, use **four-bar linkages.**
* In nature, some types of fish, like a parrotfish or moray eel, have a **four-bar linkage** in their jaws.

A **four-bar linkage** can be used to make many moveable inventions, including puppets! Animate the giraffe's head to ease in and out of the movement to respond in a series of different expressions without being too rigid.

Imagine

Make joints and assemble links

Create a four-bar linkage for the giraffe's neck

Make the head

From paper create eyes, ears, horns, and other features for the giraffe

Craft a savannah scene for your giraffe to roam

NGSS

Florida - NGSSS

Build

References and Extra Resources

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.

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: Four-Bar Linkages

Overview and Objectives

Lesson Structure

Overview