Structural materials are required to withstand a variety of applied loads in use. Understanding how these materials respond to applied loads is vital for informed materials selection. Here you can investigate how materials behave under tensile loading (loads applied along the length of a material to cause stretching).
This is only the LITE version, the full version (wtih all materials) is availabe via log-in.
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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:
To set the strain increment:
To apply strain to samples:
These instructions can be downloaded below.Download: Tensile testing quick guide
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:
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)Download: Tensile testing questions Download: Tensile Testing spreadsheet6
Watch the video and download the file below to learn about the scientific background of Tensile TestsDownload: Tensile testing background
Ohm's law is a fundamental equation that shows how voltage, electrical current and electrical resistance are related in simple conductors such as resistors. This experiments allows you to explore Ohm's law and how the coloured bands on resistors codes their resistance. In doing this you will also learn how to use a power supply and 'digital multimeters'.
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Voltage, current and resistance are the most fundamental quantities for describing the flow of electricity. Ohm’s law shows how these three quantities are related and so is a powerful way of understanding the basic nature of electricity.
This is relevant to vast areas of technology today, including national electricity grids, power generation, design of all electronic devices and all electronic circuits, heating, electrical safety and understanding of natural phenomena such as lightning. This experiment will allow you to explore Ohm’s law by making measurements of voltage, current and resistance.
Resistors are the simplest and most commonly used electronic component and almost all electronic circuits them. They can be used to change the properties of any circuit they are part of, such as current flow, how voltage is distributed across components, the speed of a circuit, the amount of amplification from a circuit, the response of a sensor or the amount of electrical heating from a circuit.
The simplest resistors are made of a thin film or wound wire of carbon or metal. They usually have a series of coloured bands that represents both their target resistance value and how much the actual value might vary from this (the ‘tolerance’). This experiment lets you practise selecting the appropriate colour bands on a resistor to achieve a certain resistance value.
Digital multimeters (DMMs) are versatile pieces of equipment commonly found in electronics, physics and engineering labs. In this experiment you’ll learn how to use a DMM to measure voltage, current and resistance. You’ll see this piece of equipment in many other FlashyScience experiments!
Download the attached file for the Quick Guide including a table of resistor colour bands (requires log in) or follow these instructions:
To measure resistance:
To change the resistor:
To use voltage and current:
Please download the attached file for full operating instructions of the Ohm’s Law experiment (requires log in)
See attached file for questions on the experiment (requires log in)
Download attached file to see background information for this experiment (requires log in)
Gravity is a fundamental force in nature, without which we would not have galaxies, stars, the Earth, oceans, life on Earth... or golf.
This experiment allows you to measure the acceleration due to gravity by measuring the time taken for a ball to fall through different heights. You can choose between two ways of timing the free fall, and you can even travel through space to measure the strength of gravity on different objects of the Solar system!
It is safe to say that gravity is important to us! Without gravity there would be no life on Earth and, in fact, without gravity, the Earth would never have existed.
Gravity is responsible for stars forming in the first place, keeping the Sun from exploding from the heat it generates, and for the structure of galaxies. It also keeps the Earth in orbit around the Sun, keeps our atmosphere and oceans in place and means we don’t float off into space. Gravity even allows plants to detect which was is ‘up’ so they send their roots and shoots in the right directions. You can see more at this NASA web page.
So, why does it matter that we know how strong gravity is?
Well, for lots of reasons.
The strength of gravity is essential to know in Civil Engineering projects such as design of
buildings and bridges so we can calculate the stresses materials are under.
Aircraft and space rocket designers must know the strength of gravity that must be overcome and satellite technology is based upon a certain strength of gravity to maintain orbits at particular heights above the Earth.
Hydroelectric power generation also relies on gravitational potential energy, either through energy ‘storage’ in dams or from the water flow or tides in rivers or oceans.
Our quality of life would be very different too. Most sports rely on gravity (we’re not counting chess as a sport here!) and gravity even keeps food in a saucepan while it cooks!
Download the one-page guide through the link to see how to operate the Free Fall experiment (requires log in).
Basic operation is as follows:
Measured Earth’s gravity? Click on the poster to explore gravity elsewhere in the Solar System too!
Click on the link to download the full operating instructions for the Free Fall due to Gravity experiment (requires log in)
Click the link to download a file with four example experiments (requires log in). These are:
Exp 1. Measurement of g using pressure pad sensor
Exp 2. Measurement of g using light gate sensors
Exp 3. Travel the Solar System!
Exp 4. Uncertainty in g based on uncertainty in individual measurements
Click on the link to download a file that explains how to calculate acceleration due to gravity (requires log in). This also describes ways of determining and combining uncertainties in experimental measurements .
Radioactive materials are used by us in lots of ways. This experiment allows you to explore alpha, beta and gamma radiation and how they are absorbed by various materials. You can also measure the change in radioactive signal with distance from the radiation source and even time travel to measure the halflife of radioactive decay for different elements!
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Radioactive elements (radionuclides or radioactive isotopes) produce high energy particles and are used in a huge range of applications. Most people know about nuclear power, which converts the energy of radiation from uranium-238 or plutonium-239 into heat and then electrical power, even in small-scale form for remote applications (e.g. spacecraft). There are far more widespread uses all around us though.
Radionuclides are used in many medicinal applications. They can be used as tracers to follow fluid flow inside the body by detecting the radionuclide emitted radiation (e.g. technetium-99, thallium-201, iodine-131 and sodium-24). Medical imaging can use radioactive elements that naturally collect in particular parts of the body and image the radioactive emission. For example, iodine-131 is used to image the thyroid and other isotopes can be used for other organs, such as bones, heart, liver and lungs. Larger doses of the radionuclides (e.g. cobalt-60) are used to create a targeted radiotherapy treatment of cancer in these organs. It is even possible to detect the presence of Heliobacter pylori (an unwanted bacterium that can be in stomachs) with a simple breath test that uses carbon-14.
You may have radioactive materials in your home, school or workplace. Smoke detectors use alpha radiation from americium-241 to ionise smoke particles for detection. Glow-in-the-dark inks on clocks, watches and emergency signs that convert radioactive particle energy from promethium-147 into light.
You may also have food that has been treated with radiation. Many foods (including tomatoes, mushrooms, berries, cereals, eggs, fish and some meat products) are irradiated with gamma rays from cobalt-60 to kill micro-organisms and improve the food’s shelf life (without making the food radioactive!). Similarly, gamma radiation from caesium-137 is used to sterilise medical products such as syringes, heart valves, surgical instruments and contact lens solutions.
Radioactive elements are used in industry too. For example, the absorption of different types of radiation mean it can be used to monitor the thickness of manufactured components and sheets. Radionuclides are also used for detecting leaks from pipes, the direction of underground pipes and waste dispersal in the environment. Radioactive sources are also used in industrial imaging, with the sample placed between the radiation source and a detector. Certain isotopes are used as chemicals in order to trace chemical reaction routes, e.g. carbon-14 in photosynthesis. Similar approaches are used in biology to test when proteins undergo important ‘phosphorylation’ reactions (using phosphorus-32) to learn when their function is activated by other proteins or small chemicals.
Radioactive elements can also be used for historical dating of objects, e.g. carbon-14 dating for estimating the age of organic matter and uranium-238 for rocks. Similarly, radioactive decay from vintage drinks such as wine can be used to prove their age, since radionuclides were released into the atmosphere by nuclear explosion tests after World War II and are present in all food and drink produced since then.
With so many uses, it’s no wonder that radioactive decay is an important aspect of science and engineering!
Download the attached file to see the full Quick Guide (requires log in) or follow the instructions below:
Select the radiation source:
Changing the filter material and thickness:
Change the source-detector separation:
Open the file below to see the full instructions for operating the Radiation experiment (requires log in):
Download the file below to see example experiments, including for GCSE and A-level (requires log in).
Or see if you can do some of the following:
Download the file below to see the scientific background of radioactive decay (requires log in)
The electrical resistivity of a wire tells us how well the wire material conducts electricity. This is crucial information for any application that involves conducting electricity, including wind turbines, electric vehicles, household electrical goods and computers. Here you can measure the resistivity of wires of different materials and widths, and consider which would be best suited for conducting electricity.
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Electronic materials are crucial to our life today, and electrical ‘resistivity’ tells us how good or poor a material is at conducting electricity.
We use materials with low electrical resistivity to transmit electrical power from generators, across grid distribution networks, and to homes and workplaces for use. Designers of electrical devices rely on knowing the resistivity of wire used in order to calculate the resistance of components.
These devices range in size from enormous machines such as wind turbines or industrial lifting equipment; motors or engines in electric vehicles and all-new electric aircraft; consumer products such as washing machines, hair dryers and ovens; and the nanoscale components within the computer chips found in smart devices, laptops, and mobile phones.
In fact, modern computing is based on controlling the resistivity of semiconductor materials in a type of transistor (known as ‘field effect transistors’ using ‘CMOS’ technology).
Measuring electrical resistivity helps us to understand the properties of materials, to monitor manufacturing processes, and to select the best material for an application.
Click on the link below to download the Quick Guide for using the Resistivity experiment. Or follow the brief instructions here:
Click on the link to download a pdf of the Instructions for operating the Resistivity experiment
Click on the link below to download a pdf of example questions for the Resistivity experiment.
Click on the link to download the Background pdf for the Resistivity experiment.
Hooke's law describes how springs respond to having forces applied. This experiment allows you to apply force using weights and measure how springs of different stiffness extend in response. You can calculate the stored elastic potential energy in the springs and even go to different parts of the Solar System to see how changing the strength of gravity changes the weight applied to the springs!
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Stretching – the truth!
You may wonder why we study springs and why questions about stretching springs appear on exams. Sure, springs are used in the world, but are they really so important? Why is it important to know how springs stretch when they are pulled?
Well, first, springs are incredibly useful. When made from elastic materials, such as most metals, springs stretch when pulled and return to their original size when released. They can also be compressed and, again, return to their original size when released. The stretching or compression stores energy that is then returned when the spring is released. This energy storage and return is the key reason springs are useful. Springs use this capability in all sorts of applications, including in high tech areas such as automotive, industrial tools and robotics, to more everyday items such as trampolines, mattresses, children’s play equipment, door handles and retractable pens.
The second reason is that the way that springs respond to force being applied to them (i.e. being pulled or mass added to one end of them) is identical to how materials in general behave. If materials are pulled, then they stretch. The coiled shape of a spring, though, means that the ends tend to move large distances compared to a regular shape of the same material (e.g. a simple rod). This means that studying what happens to springs when they are pulled allows simple measurements to be performed that give us understanding of how all materials behave when they are pulled. Materials behave this way in any application where they have force applied to them, e.g. in construction, vehicles, heart valves, body implants, plants, rocks, furniture, tools, footwear – the list goes on and on. And don’t forget this includes your body too!
Use this experiment to find out more!
Follow these instructions or download the Quick Guide via the link (requires log in):
5. To change to a different part of the Solar System:
6. Click the Information button to see the controls.
Use this experiment to:
Download the full Instructions for the Hooke's Law experiment from the link (requires log in)
There are lots of activities to do with the Hooke's Law experiment. Download the Questions from the link (requires log in)
Download the file from the link below to see the full scientific Background to the Hooke's law experiment (requires log in)