Physics 

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:

1. Click on the right hand wire post to move to the Select Wire screen.
2. Open the micrometer by dragging the thumbwheel down.
3. Choose a material and drag the unlabelled wire into the micrometer.
4. Close the micrometer and measure the wire's width.
5. Click on the wire while it's in the micrometer to return to the main screen.
6. Click on the switch to turn it on.
7. Measure voltage and current for a variety of contact positions on the wire.
8. Calculate resistance for each contact position. 
9. Plot resistance vs contact position and calculate the gradient of a line of best fit.
10. Multiple the line's gradient by the wire's cross-sectional area to obtain the wire's electrical resistivity.

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.

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):

1. Click on 50 g or 100 g masses to add them to the mass holder.
2. Click on the ruler to go to a zoomed view (centimetre scale).
3. Click on the masses on the holder to move them back to their boxes.
4. To change to a different spring:

• Remove all mass from the holder.
• Click on the spring.
• Select from Low, Medium, High or Unknown Stiffness.
• Click again on the spring to return to main screen. 

5. To change to a different part of the Solar System: 

• Remove all mass from the holder.
• Click on the poster to choose where to do the experiment!

6. Click the Information button to see the controls.

Use this experiment to:

• Test Hooke’s law.
• Measure spring constants.
• Test the ‘limit of proportionality’ for springs.
• Calculate the stored energy of a spring.
• See how different strengths of gravity affect the weight added to a spring.

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. You can choose these from one of our Activities, with step-by-step instructions, and record your work on a Worksheet, or use the shorter descriptions in our Questions. Download all of these from from the links (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)

There are lots of ways that we use materials that see them change temperature. Some examples include heating systems in buildings (especially storage heaters), simple household appliances such as an iron or an oven, combustion engines in cars, jet engines in aircraft, high speed machines such as drills, and industrial furnaces; however, examples also include applications where the temperature is reduced, for example in refrigerators, freezers and heat sinks, which are used to help cool another component.

A change in a material’s temperature will also result in a change in its heat energy. Different materials, however, will have a different change in heat energy for a given change in temperature.

The materials property we use to show this difference is called specific heat capacity. This property is key to allowing us to understand how components will perform in thermal applications and help us to choose the most appropriate material. If you go to study Physics or Engineering at university you will probably also learn how specific heat capacity values depend on a material’s types of atom, atomic bonding and electrical properties.

Download the attachment to see the one-page quick guide (requires login) 

Download the attached file to see the full instructions for this experiment (requires login)

There are two files to download here, both requiring a login first.

The 'Activities' download gives full step-by-step instructions for four activities with this experiment

The 'Worksheets' download provides worksheets for these four activities that can be printed out and written on directly. 

Download the attached file to see the scientific background to this experiment (requires login)

The FlashyScience Acceleration and Force experiment might use a toy car on a table top but the science you can learn from it helps us to understand the world around us, to design all sorts of new vehicles and machines, and even to understand our bodies better.

At the largest of scales, knowing the huge forces involved with galaxies, stars and planets show us how these huge objects move and even how they form. We use our knowledge of force and acceleration to launch objects into space using rockets and to put satellites into stable orbits. This knowledge also allows us to calculate the acceleration of high performance cars (e.g. F1 cars) and aircraft, to design and build machines with moving parts, and to understand the forces parts of our bodies experience through an area of science called biomechanics. Force and acceleration can even be used to measure the mass of atoms and molecules through scientific techniques called mass spectrometry, and help us to understand how atoms interact in gases.

You can see that knowledge of force and acceleration is essential to lots of areas of science, engineering and our lives in general. Why not try out the FlashyScience Acceleration and Force experiment to learn more for yourself?

Download the quick guide for the Acceleration and Force experiment below (requires login)

Download the full instructions for the Acceleration and Force experiment (requires login).  

The attached activities and associated worksheets are suitable for different levels (needs login to view).

Download the file below to read about the background theory to the Acceleration and Force experiment (requires login). This includes different levels for GCSE Foundation and Higher Levels, and A-level Physics. 

Density is a basic property of materials and liquids. It is important in all sorts of areas of science, engineering and medicine. Density (mass per unit volume) is related to the type of atoms within the material or liquid and how they are arranged. Changing the temperature of a solid or liquid often changes its volume, which also changes its density . Different processing treatments of materials can lock in some of these changes, resulting in materials made of the same atoms but with different densities. Many materials can be ‘porous’ (contain lots of holes) and being able to measure density is a simple way of finding the level of porosity of a material.

The buoyancy of a solid in a liquid depends upon the density of the solid and liquid. Ice floats in liquid water because ice molecules are more widely spaced than those in water, and so the density of ice is lower than that of water.

The density of solids and liquids is also related to a substance’s refractive index and how it interacts with X-rays. For example, your bones are denser than your muscle tissue and so absorb X-rays more; this allows medical images to be created that show the different regions inside your body.

Density is vital to the efficient design of physical objects, particularly for structural and transport applications. There is a huge demand for engineers and materials scientists to create lighter vehicles and aircraft to reduce their power requirements and help reduce our use of fossil fuels.

The FlashyScience Density of Solids & Liquids experiment allows you to develop your scientific and engineering skills in measuring density in three different ways. Why not give it a try?

Download the quick guide for the Density of Solids & Liquids experiment below (requires login)

Download the full instructions for the Density of Solids & Liquids experiment (requires login).  

The attached activities and associated worksheets allow you to use the Density of Solids & Liquids experiment in lots of ways (needs login to view). These activities are for:

1. Regular objects: cube and cuboid
2. Sphere
3. Irregular objects
4. Liquids

Download the file below to read about the background theory to the Density of Solids & Liquids experiment (requires login).

The thermal conductivity of materials is hugely important for how we live today.

Thermally-insulating materials are found in lots of places around the home. This includes safety items such as oven gloves or fire blankets and inside ovens and refrigerators to stop them heating or cooling the rest of your kitchen! Your hot water pipes and water heating system will probably have thermal insulation around them to stop unwanted heat loss. Houses and other buildings usually have thermal insulation around them to reduce heat loss when it is cold outside and reduce heat entering when it is very hot outside. This is important as we try to reduce CO2 emissions from energy use as part of our fight against climate change. Insulating materials are also used around industrial furnaces, in refrigerated vehicles and packages (e.g. for transporting food or medical supplies) in aircraft to keep crew and passengers warm in the cold air, and in spacecraft to stop the insides reaching temperature extremes and protecting the spacecraft itself from burning up if it re-enters Earth’s atmosphere.

Thermally-conducting materials are also very important to heating and cooling systems, such as heating elements in kettles and furnaces, radiators, high speed industrial machines and heat-sinks found in electronic devices.  

Heat conduction is also really important in many renewable energy technologies, such as solar cells (photovoltaics), which work less efficiently if they heat up, and ‘thermoelectric generators’ (TEGs), which are most efficient if they conduct electricity well but conduct temperature weakly.

This huge range of applications means there is a lot of research and development of materials with new thermal conduction properties. How materials conduct heat is also related to their atomic-scale structure – this means that we can learn about the materials from how they conduct heat and change their structure in order to create new properties that are better suited for particular applications. There’s so much to find out! For now, why not start with the FlashyScience Thermal Insulation experiment?

Click below to download the Quick Guide pdf (requires login)

Click below to download the Thermal Insulation Instructions (requires login)

The instructions and worksheets for the following activities can be downloaded using the links below (requires login):

Activity 1: Effect of a material as thermal insulation

Activity 2: Comparison of different materials as thermal insulation

Activity 3: Effect of material thickness on heat conduction

Activity 4: Effect of temperature difference on its rate of change (Advanced Experiment) 

Click below to download the Thermal Insulation Background pdf (requires login)

Any object emits electromagnetic radiation due to having a temperature above absolute zero (about -273.15°C), although different surfaces emit the radiation to different levels. This might seem like a curiosity created just for lab measurements but it has lots of real-world relevance.

The hotter an object is, the stronger this thermal emission is. Objects with different temperatures emit different parts of the electromagnetic spectrum too. Objects close to room temperature (like us!) only emit infrared radiation (‘IR radiation’), which we feel as warmth. Objects at hundreds of degrees Celsius start to emit visible radiation (wavelength from 400 – 700 nm), those at thousands of degrees Celsius emit ultra-violet (UV) radiation (wavelength from 100 – 400 nm), while the hottest objects in the galaxy (e.g. regions around black holes) emit X-ray radiation (wavelengths shorter than 100 nm).

The most important aspect of thermal emission is that life on our planet would not exist without it! Our nearest star, the Sun, is so hot its IR emission reaches across over 140 million kilometres (that’s over 90 million miles) of space to warm our planet. The Sun’s visible light also allows us to see. The Earth’s ozone layer plays an important role in absorbing most of the UV light from the Sun, which would otherwise reach us at harmful levels.

Astronomers also use the thermal emission from other stars and astronomical objects to learn about how they were formed, their lifecycle, and the processes that go on within them.

Climatologists and meteorologists (scientists who study the Earth’s climate and weather) use satellites to map the IR emission of the Earth’s atmosphere and land to help predict future weather events and trends. The surface of the Earth can also be imaged to locate underground heat sources, objects and water flows.

In smaller-scale applications, surface materials are often chosen to help either cool or insulate an object by either maximising or minimising IR emission, depending on what is needed. IR emission is used in some household or industrial heaters and to measure temperature in areas such as industrial manufacturing processes and medical applications, e.g. measuring the temperature of a patient.

‘Thermal imaging’ cameras create images from IR emission for a huge range of applications, including night vision (e.g. for security systems or non-invasive imaging of wild animals), analysing heat sources in electronic circuits, industrial monitoring (e.g. web servers, aircraft engines), and analysing the thermal efficiency of objects from miniature devices to houses.

Use the link below to download the one-page quick (requires login):

Download the Full Instructions for the Leslie cube experiment by clicking on the link below (requires login):

The instructions and worksheets for the following activities can be downloaded using the links below (requires login):

Download the Background theory file by clicking on the link below (requires login):