Lesson Notes By Weeks and Term v4 - SHS 3

Lesson Video

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Performance objectives

• Explain the function and importance of diagnostic devices.
• Identify the components of a simple diagnostic device.
• Design and construct a basic diagnostic device.
• Disassemble and reassemble a device, identifying parts.
• Present your diagnostic device project to the class.

Lesson summary

This lesson introduces the fundamental principles behind diagnostic devices, the tools that doctors, nurses, and scientists use to understand what is happening inside our bodies. From the simple thermometer used at the CHPS compound to the blood sugar monitor (glucometer) used by a relative with diabetes, these devices are all around us. Understanding how they work is the first step to being able to repair, improve, or even invent new ones. This lesson will move beyond theory to give you the hands-on skills to understand, design, and assemble a simple diagnostic device, empowering you as a future scientist, engineer, or healthcare professional in Ghana.

Lesson notes

2.1 What is a Diagnostic Device?

A diagnostic device is any tool, instrument, or system used to gather information about a patient's health status to help diagnose a disease or medical condition. Simple Example: A mercury-in-glass thermometer. It measures body temperature to help diagnose a fever. Complex Example: A Magnetic Resonance Imaging (MRI) machine. It uses powerful magnets and radio waves to create detailed images of organs and tissues inside the body. 2.2 The Core Principle: How ALL Diagnostic Devices Work

Almost every diagnostic device, no matter how simple or complex, follows a four-step process. Understanding this is key to designing your own.

Sample → Transducer → Signal → Output

Evaluation guide

• Design and construct a simple diagnostic device/assemble the units of a medical device.
• Project- Based Learning: Learners work in mixed -ability groups to design and build a diagnostic
• medical device such as a thermometer, heartbeat monitor, breath alcohol monitor, paper -based
• colorimetric sensors, etc. Learners may consult existing literature and experts, review exis ting

Reference guide

• . Plan the steps for construction. (e.g., "We will need filter paper, glucose oxidase, peroxidase, potassium iodide, and a buffer solution. We will create small circles on the paper for the test zones.")
• Build a Prototype: Create the first version of your device.
• Test & Evaluate: Use known samples (e.g., plain water, sugar solution) to see if it works. Does it give the expected results? Is it reliable?
• Refine & Improve: Based on test results, what can be made better? Is the colour change clear enough? Does it last long enough? Repeat the process until the device works well.
• 4 Focus Project: Building a Paper-Based Glucose Sensor
• This is a simple, low-cost diagnostic device that demonstrates all the principles above. It works similarly to the urine test strips used to monitor diabetes.