Centripetal Slime Rheology & Barus Weissenberg Effect

45 mins Ages 10-14 Indoor

A challenging, hands-on discovery and STEM project designed for curious young minds aged 10 to 14.

• Clear or white PVA school glue (1/2 cup)
• Borax powder (dissolved in water) (1 tablespoon)
• Tall glass beaker or plastic tumbler (1 unit)
• Smooth wooden dowel (1/2 inch thick, 15 cm long) (1 unit)
• Variable-speed cordless drill or motorized craft motor (adult use) (1 unit)
• Safety goggles (1 pair)

→ Prepare cross-linked slime with PVA glue, water, and borax activator until it forms a stretchy, viscoelastic polymer.
→ Normal liquids (like water) fly outward due to centrifugal forces when stirred with a spinning rod.
→ Viscoelastic slime does the opposite: normal stress forces cause the polymer chains to wrap and climb up the rotating vertical rod.
→ Operate the electric drill or rotating mixer at low, controlled RPM.

Tie back long hair; adult operates the drill or rotating shaft at low RPM. Wear safety goggles.

Your anonymous feedback helps us recommend better activities.

Step-by-Step Instructions

Mix 1/2 cup PVA glue with 1/2 cup water and tint with food coloring in a tall glass beaker.

Stir in 2 tablespoons of borax solution (1 tsp borax in 1 cup warm water) until the mixture cross-links into a stretchy slime.

Secure a smooth wooden dowel into the chuck of a variable-speed cordless drill (adult supervision).

Lower the dowel into the beaker and spin slowly: observe the Weissenberg effect as the slime defies centrifugal forces and climbs the rod.

Non-Newtonian fluid rheology The Weissenberg Effect (rod-climbing normal stress) Viscoelastic polymer cross-linking