Resources: A variety of surfaces (different carpets or carpet tiles, a variety of wooden floors, tarmac/playground surface), trainers, a Newton meter, a ruler and a weight. Alternatively, the children could cover a plank of wood with different surfaces (e.g. sandpaper, a towel, tinfoil, lino, carpet, corrugated cardboard and bubble wrap). A ruler or tape measure.
Core Handout (2): A results table for children to gather their data.
Stretch Handout (3): Questions for children to apply their knowledge of friction to everyday situations.
Enquiry Approach - Comparative / fair testing
Conducting a test that controls all but one variable to answer a scientific question.
Enquiry Skill - Setting up tests
Carefully following a method and using equipment accurately to carry out a scientific enquiry. The method may be designed by teachers or children themselves.
Recap previous learning by describing the difference between air resistance and gravity. Gravity is the force which draws objects towards the centre of a planet (or other body) and air resistance is friction which acts between the air and another object. Discuss how objects are designed to be streamlined to lessen the impact of air resistance.
The children will rub their hands together to demonstrate friction. Friction is the resistance force between two surfaces when they move across each other. It is a contact force which works in the opposing direction to an object’s movement.
Explore examples of when friction is useful, such as rubber brakes on tyres, shoe soles and tyres on the road. In the winter, sand/salt is spread over the road to increase friction and prevent car tyres from slipping. Lubricants are used to help surfaces move over one another more smoothly. Ask the children to sort surfaces from high friction to low friction.
Discover what a Newton meter is and how to use it accurately and carefully.
Career Film: Take a tour around Rolls Royce SMR's Heritage Museum in Derby to find out about Sravani Murtinty's job. Sravani works as a Component Design Engineer for Rolls Royce SMR.
Expert Film: This is Imane Holles. Imane works as the Senior Verification Engineer for Rolls Royce SMR. Listen to Imane as she describes the effects of friction on different surfaces.
Ask the children to investigate the best surface to place on a floor to prevent people from slipping. Predict and then use a Newton meter to measure the force required to make a shoe slide across a range of surfaces. The shoe should contain a weight. The children can use different surfaces available to them around school; alternatively, they can fix a variety of surfaces to a wooden board. They should then present their results in a bar chart.
Challenge Task: Ask the children to answer the questions to summarise their conclusions and apply the knowledge they have gained to real-life situations.
Ask the children to share their conclusions. Which surfaces provided the most and least amounts of friction? Did any surfaces surprise them?
Friction is a force that opposes the motion of an object as it moves across a surface. The effects of friction on different surfaces can vary, depending on a number of factors, including the type of surface, the force applied to the object, and the texture of the surface.
Smooth surfaces: On smooth surfaces, such as glass or metal, the effects of friction are relatively small. This is because the surfaces are very flat and have few irregularities to create friction. As a result, objects tend to slide easily across smooth surfaces, and there is little resistance to their motion.
Rough surfaces: On rough surfaces, such as concrete or sandpaper, the effects of friction are much greater. This is because the surfaces are covered in irregularities, such as bumps and ridges, that create friction as an object moves across them. As a result, objects tend to move more slowly across rough surfaces, and there is more resistance to their motion.
Soft surfaces: On soft surfaces, such as carpet or grass, the effects of friction can be significant, but are different from those on hard surfaces. In these cases, the texture of the surface can cause objects to sink in slightly, increasing the surface area in contact with the object and creating friction. The amount of friction on soft surfaces can also depend on the force applied to the object, with more force generally leading to greater friction.
Fluids: In fluids, such as water or air, the effects of friction are also different. In these cases, the fluid can create resistance to the motion of an object, known as drag, which is similar to friction. The amount of drag on an object moving through a fluid depends on factors such as the speed and size of the object, as well as the viscosity and density of the fluid.
In conclusion, the effects of friction on different surfaces can vary widely, depending on a variety of factors. Smooth surfaces tend to have low friction, while rough surfaces and soft surfaces can have much greater friction. In fluids, drag can create resistance to the motion of an object. Understanding the effects of friction on different surfaces is important for a variety of applications, from designing sports equipment to creating effective braking systems for vehicles.