Engineering: The challenge of temperature

Introduction

In this unit we examine one factor that very often seems to be found skulking around close to problems and solutions: temperature.

Almost whatever we do, wherever we are, temperature changes. Stay in the same spot and you'll find daytime and night-time temperatures can be markedly different. You may even find significant changes in temperature during the day. When moving you can encounter more rapid variations. For example, an aircraft might leave a tropical runway where the air temperature is thirty degrees Celsius and climb within minutes to a height where the outside temperature is minus fifty degrees.

It turns out that almost all the properties of a material change with temperature. So, anything you make will to some extent be sensitive to temperature. That sensitivity needs to be known about. ‘What if the temperature changes?’ is an excellent prompt for engineers.

There are advantages and disadvantages to thermal sensitivity and some of these are explored in her. On the one hand, we can do amazing things with thermal energy, such as moving matter around within a solid without risking melting or changing the basic shape of a component. On the other hand, it can be a real nuisance. It can make magnetic disks ‘forget’. It can leave materials ‘sapped’ of their strength. Just a few degrees of temperature change can make some things unrecognisably different. Temperature really does present a universal challenge that must be faced – ignore it at your peril.

This unit is an adapted extract from the Open University course Engineering: mechanics, materials, design (T207). [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)]