Physics 

What is ‘Tensile Testing’?

The ‘tensile’ properties of a material describe its most basic mechanical behaviour – how much does a material stretch when it is pulled and how much of the stretching is permanent? ‘Tensile Testing’ is the process of measuring a material’s tensile properties.

Why are tensile properties important?

Understanding of tensile properties is vital for any application that uses materials structurally, i.e. to withstand or apply force. The range of uses this covers is enormous. Strong and stiff structures are used in vehicles (cycles, cars, trains, aeroplanes, spacecraft), bridges and buildings, sports equipment and bio-implants (e.g. hip joint replacements). Flexible materials are also used in many of these applications. Thin but robust materials are used in touchscreens. Hard materials are used in machines and robots that process and shape other materials and as durable coatings that improve the performance and lifetime of aerospace and bio-implant components. Elastic materials can be stretched enormously before any permanent change is made and are used in springs and high performance fabrics. And it’s not just how a component is used – many manufacturing processes involve changing a component’s shape or response to applied forces, e.g. extrusion to make tubes, beams and bottles; drawing to make springs or wires; or forging and rolling to shape and harden metals.

To select a sample:

• Click the lower jaw to go to the sample view.
• Open the calliper jaws, drag a sample of choice between the jaw and fully close the jaws around it. In this LITE version you can only select one of the samples)
• Use the Vernier scale to measure the sample width.
• Click the sample held in the callipers to use it in the tensile testing machine
• Or open the callipers, return the sample to its original position and choose another sample. (Only available in the full version)

To set the strain increment:

• Click the Set button (display starts to flash)
• Use the keypad and the Del button to enter the desired Step value
• Click the Set button again (display stops flashing)

To apply strain to samples:

• Set the strain increment value as described above.
• Click the up arrow to increase the applied strain by the Step increment value.
• Click the down arrow to decrease the applied strain by the Step increment value.
• Measure (and record) the applied load (force) using the needles on the Load dial.
• Turn off the strain control unit and click on the lower sample holder to select a new sample.

These instructions can be downloaded below.

Download the file below for the full instructions, including background, relevance, operating instructions and questions.

Structural materials are required to withstand a variety of applied loads in use. Understanding how these materials respond to the applied loads is vital for informed materials selection. Here we investigate how materials behave under tensile loading (loads applied along the length of a material to cause stretching).

The Tensile Test experiment allows a number of mechanical tests to be performed on materials, including:

• Determination of full stress-strain curve to fracture, using either ‘engineering’ or ‘true’ value
• Observation of elastic behaviour and calculation of Young’s modulus
• Observation of the onset of plastic behaviour and permanent deformation
• Calculation of moduli of resilience and toughness
• Calculation of strain energy in a system
• Calculation of work done in deforming a sample

The Tensile Testing experiment can be used for a wide range of investigations.

This downloadable pdf below contains a range of example short and long questions.

We have also provided a spreadsheet file to allow you to enter your SAMPLE WIDTH, STRAIN and APPLIED LOAD data and obtain stress-strain plots. (HINT: to investigate the general form of stress-strain curves with younger students, use a default sample width of, say, 7 mm)

Watch the video above and download the file below to learn about the scientific background of Tensile Tests

Thermodynamics and engine cycles are relevant to most areas of technology and science.

The behaviour of gases is used directly in applications as diverse as compressors, refrigerators, power generation from steam-driven turbines (used in gas-fired, coal-fired or nuclear power stations), pumping of gases (from natural gas pipe networks to aqualungs), and transport vehicles using petrol and diesel engines (combustion engines), jet and rocket engines, high performance tyres (e.g. for F1 cars) and even hot air balloons!

Thermodynamics is relevant far more widely though and to any system in which there is a change in energy, volume or ordering. This is relevant to almost every process around us, from sub-atomic particles forming atoms to the expansion of the universe and taking in atoms bonding to make a molecule or crystal (Physics), molecules reacting with each other (Chemistry), all biological processes (Biology), the weathering of rocks and tectonic plate movement (Geology). Even your breathing while you read this and your eye converting light into electrical signals so you can read
this are thermodynamic processes. All energy technologies, materials manufacturing or recycling, chemical processing, transport technologies and
even information technologies rely upon the principles of thermodynamics.

Thermodynamics and gas laws are, therefore, incredibly important topics. The FlashyScience Gas Laws virtual experiment allows you to start to explore this fascinating area of science and engineering.

Download the attached Quick Guide for easy instructions (log in required)

Also, download the ‘How To’ attachments for step-by-step instructions on conducting experiments for:

• Constant pressure
• Constant temperature
• Constant volume

Download the attached file to see the full operating instructions for the Gas Laws experiment (requires log in)

​Download the attached file to see lots of Gas Laws experiments and questions (requires log in).

Here are a few simple suggestions for you to start exploring how ideal gases behave:

1. Adiabatic changes (P, V and T all variable) - Increase the pressure and observe the effect this makes on the volume and temperature.
   
2. Constant pressure (isobaric) – Charles’ law. Turn on the Heat jacket. Change the temperature and see the effect this makes on the cylinder volume.
   
3. Constant temperature (isothermal). Turn on the Heat Jacket to keep the temperature constant. Change the pressure and see what happens to the cylinder volume.
   
4. Constant volume (isovolumetric) – Gay-Lussac law. Note the initial piston height h₀. Alternately change the pressure when the Insulation jacket is in place and then adjust the temperature with the Heat jacket in place to bring the piston back to height h₀. How do P and T vary to achieve this?
   

​Download the attached file to see the Background science behind the Gas Laws experiment (requires log in)

What is ‘Tensile Testing’?

The ‘tensile’ properties of a material describe its most basic mechanical behaviour – how much does a material stretch when it is pulled and how much of the stretching is permanent? ‘Tensile Testing’ is the process of measuring a material’s tensile properties.

Why are tensile properties important?

Understanding of tensile properties is vital for any application that uses materials structurally, i.e. to withstand or apply force. The range of uses this covers is enormous. Strong and stiff structures are used in vehicles (cycles, cars, trains, aeroplanes, spacecraft), bridges and buildings, sports equipment and bio-implants (e.g. hip joint replacements). Flexible materials are also used in many of these applications. Thin but robust materials are used in touchscreens. Hard materials are used in machines and robots that process and shape other materials and as durable coatings that improve the performance and lifetime of aerospace and bio-implant components. Elastic materials can be stretched enormously before any permanent change is made and are used in springs and high performance fabrics. And it’s not just how a component is used – many manufacturing processes involve changing a component’s shape or response to applied forces, e.g. extrusion to make tubes, beams and bottles; drawing to make springs or wires; or forging and rolling to shape and harden metals.

To select a sample:

• Click the lower jaw to go to the sample view.
• Open the calliper jaws, drag a sample of choice between the jaw and fully close the jaws around it.
• Use the Vernier scale to measure the sample width.
• Click the sample held in the callipers to use it in the tensile testing machine
• Or open the callipers, return the sample to its original position and choose another sample.

To set the strain increment:

• Click the Set button (display starts to flash)
• Use the keypad and the Del button to enter the desired Step value
• Click the Set button again (display stops flashing)

To apply strain to samples:

• Set the strain increment value as described above.
• Click the up arrow to increase the applied strain by the Step increment value.
• Click the down arrow to decrease the applied strain by the Step increment value.
• Measure (and record) the applied load (force) using the needles on the Load dial.
• Turn off the strain control unit and click on the lower sample holder to select a new sample.

These instructions can be downloaded below.

Download the file below for the full instructions, including background, relevance, operating instructions and questions.

Structural materials are required to withstand a variety of applied loads in use. Understanding how these materials respond to the applied loads is vital for informed materials selection. Here we investigate how materials behave under tensile loading (loads applied along the length of a material to cause stretching).

The Tensile Test experiment allows a number of mechanical tests to be performed on materials, including:

• Determination of full stress-strain curve to fracture, using either ‘engineering’ or ‘true’ value
• Observation of elastic behaviour and calculation of Young’s modulus
• Observation of the onset of plastic behaviour and permanent deformation
• Calculation of moduli of resilience and toughness
• Calculation of strain energy in a system
• Calculation of work done in deforming a sample

The Tensile Testing experiment can be used for a wide range of investigations.

This downloadable pdf below contains a range of example short and long questions.

We have also provided a spreadsheet file to allow you to enter your SAMPLE WIDTH, STRAIN and APPLIED LOAD data and obtain stress-strain plots. (HINT: to investigate the general form of stress-strain curves with younger students, use a default sample width of, say, 7 mm)

Watch the video above and download the file below to learn about the scientific background of Tensile Tests