Materials Demonstrations

See also: Polymers

Materials science examines the properties and uses of the substances we rely on, from natural resources to modern synthetic products. This category looks at what makes different materials suitable for particular purposes, and how their characteristics can be explained by their structure. Studying materials links science to design, technology, and engineering.

Demonstration	Materials	Difficulty	Safety	Summary
Ball and Ring Expansion	★★★	★☆☆	★★☆	This demonstration shows the thermal expansion of metals. A metal ball can pass through a ring at room temperature, but when heated, it expands and no longer fits. Cooling the ball in water allows it to contract and pass through again.
Gallium and Aluminium Can	★★★	★☆☆	★★☆	When liquid gallium is applied to an aluminum can, it penetrates the aluminum’s grain boundaries and disrupts its crystal structure, making the can brittle and easy to puncture.
Freezing a Bouncy Ball in Liquid Nitrogen	★★★	★★☆	★★★	A bouncy ball submerged in liquid nitrogen loses its elasticity because the extreme cold freezes its rubber molecules into a rigid, brittle structure. As a result, the ball cannot compress and rebound, making it unable to bounce until it warms up again.
Melting Gallium in Your Hand	★★★	★☆☆	★★☆	Gallium, a metal with a melting point of 29.76 °C (85.6 °F), can melt in the palm of your hand. The demonstration shows how body heat is enough to turn solid gallium into a silvery liquid.
Nitinol Shape Memory Alloy	★★★	★☆☆	★★☆	Nitinol, a nickel-titanium alloy, demonstrates shape memory by returning to a pre-set shape when heated. Unlike ordinary wire, Nitinol “remembers” its original form and straightens itself when exposed to sufficient thermal energy.
Bimetallic Strip Thermostat	★★☆	★☆☆	★★☆	This demonstration uses a bonded copper–steel strip to show how temperature changes cause mechanical movement. Because the metals expand at different rates when heated, the strip bends, illustrating the principle of differential thermal expansion. This effect underpins many real-world devices, such as thermostats and circuit breakers, where heat is converted into mechanical motion for control purposes.
Heat Conduction of Different Materials	★★☆	★★☆	★★☆	This demonstration shows how heat conduction varies in different materials by using rods of copper, iron, and glass. Wax is used to attach small nails to the ends of the rods, and the heat from a Bunsen burner causes the nails to drop off in the order of conductivity.
Forensic Fiber Analysis	★★☆	★☆☆	★☆☆	Forensic scientists analyze fibers from crime scenes using tests such as burn analysis and polarized light microscopy. These methods reveal whether a fiber is natural or synthetic and help investigators narrow down suspects without destroying evidence.
Metal Rod Conduction	★★☆	★☆☆	★★☆	A metal rod is heated at one end, and pieces of wax attached along its length melt one by one. This demonstrates how heat is conducted through the solid from the hot end toward the cooler end.
Making Casein Plastic	★☆☆	★☆☆	★☆☆	Heating milk and mixing it with vinegar causes the protein casein to separate and form curds. These curds can be dried and kneaded into a moldable bioplastic that hardens over time, demonstrating polymer formation.
Making Slime	★☆☆	★☆☆	★☆☆	This activity demonstrates polymer chemistry by making slime from glue, baking soda, and contact lens solution. Crosslinking between polymer chains in glue changes the liquid into a stretchy, rubbery material with unique properties.
Paper Recycling	★☆☆	★☆☆	★☆☆	This activity and explanation show how paper is recycled, both industrially and at home. Paper fibers can be broken down into pulp, cleaned, and re-formed into new paper products, reducing the need for tree harvesting and helping conserve natural resources.
Pencils Through a Bag	★☆☆	★☆☆	★☆☆	When pencils are pushed through a water-filled plastic bag, no water leaks out.
Rubber Chicken Bones	★☆☆	★☆☆	★☆☆	Clean chicken bones are soaked in vinegar so the acid reacts with calcium carbonate in the bone, removing minerals and leaving the collagen matrix flexible. After drying, the bones can harden in their new shape.
Simple Heat Conduction Experiment	★☆☆	★★☆	★★☆	This experiment compares how well different materials - metal, wood, and plastic - conduct heat by observing how quickly butter melts on each spoon after being heated in boiling water. The results demonstrate that metals conduct heat much more effectively than wood or plastic.

Materials
★☆☆ Easy to get from supermarket or hardware store
★★☆ Available in most school laboratories or specialist stores
★★★ Requires materials not commonly found in school laboratories

Difficulty
★☆☆ Can be easily done by most teenagers
★★☆ Available in most school laboratories or specialist stores
★★★ Requires a more experienced teacher

Safety
★☆☆ Minimal safety procedures required
★★☆ Some safety precautions required to perform safely
★★★ Only to be attempted with adequate safety procedures and trained staff