Obleck (a mixture of cornstarch and water) is a fascinating example of a non-Newtonian fluid. Its viscosity doesn't behave like a normal fluid. Here's how its viscosity changes with force:

* Low Force: When a small force is applied, obleck acts like a liquid. It flows easily and spreads out.

* High Force: When a strong force is applied, the cornstarch particles within the mixture get closer together, locking into place and resisting flow. This makes obleck act like a solid, capable of supporting weight.

Here's a breakdown of the relationship:

* Force increases, Viscosity increases: As you apply more force, the cornstarch particles have less space to move. This increases friction and resistance to flow, hence increasing the viscosity.

* Force decreases, Viscosity decreases: As you reduce the force, the cornstarch particles have more space to move around. This decreases friction and resistance, making the viscosity lower.

Why this happens:

* Cornstarch's structure: Cornstarch particles are irregular and have a lot of surface area.

* Water's role: The water allows the particles to move around, but also creates friction between them.

* Force alters particle arrangement: When you apply force, you squeeze the particles together, reducing the space for water molecules to move. This increases friction and resistance.

In short, obleck is a shear-thickening fluid. This means its viscosity increases with increasing shear stress (force). This unusual property makes obleck fun to play with and has potential applications in various fields like protective gear, shock absorbers, and even robotic control.