Magnets and gravity, pressure and pulleys, skidding, spinning and stress – investigate forces by applying pressure, building structures and balancing weights
Exhibition requirements

• A gallery with about 50 sq metres of open floor space
• Electrical power
• The exhibition must be supervised at all times when in use, preferably by staff accustomed to working in an interactive environment

Exhibit list

Balance Table – place weights onto a balance table which pivots at its centre; try to balance three differently weighted beams by moving their centres of gravity
Centre of Gravity – try to balance a variety of shapes on a pivot, some with weights attached, to find their centres of gravity. Find the balance points of models with high and low centres of gravity
Direction of Forces – lift a drawbridge’ by pulling on strings through a ‘castle wall. The difficulty relates to the angle of pull; turn a wheel by moving a connecting rod back and forth on a slider (a crank)
Magnetic Pendulum – swing a pendulum magnet above a surface with magnets set in it to see the erratic response to the attracting and repelling forces
Magnets – place various materials between two different pairs of large ring magnets mounted on rods facing one another. Turn small magnets and other materials around a cluster of large magnets
Pressure – press a range of different sized stampers into a foam rubber surface. The effort required to push down to the same degree shows the importance of the size of area over which force is applied
Pulleys – three identical springs can be stretched by pulling three cords. Each is attached to a different pulley arrangement, which determines the distance you have to pull them and the effort required
Resolution – make a pointer move in specific directions by pulling on a combination of three strings. Another pointer is moved by pulling on a number of different strings attached.
See Stress – polarized light is used to show the internal stresses of shapes as they are twisted, also to observe the significance of sharp and rounded corners in concentrating the stress lines
Skid Test – a model car runs down a ramp; investigate the stopping distances on two different surfaces by applying different combinations of front and rear brakes
Spinning Tops – fix small weights onto a number of tops which differ of differing diameter and thickness to observe the effect on the way they spin
Structures – create an arch bridge between two fixed supports with wooden blocks; use another structure to investigate the importance of triangulation in giving rigidity to it