Oobleck Experiment

Oobleck is a "non-Newtonian" fluid—meaning it does not obey Newton’s laws of fluid motion—obtained from a mixture of cornstarch and water, and it draws attention in the science world due to its physical properties. Such substances alter their flow characteristics depending on the applied force force or pressure. Oobleck is not merely a fun only experiment but also an example that aids in the deeper understanding of physical and chemical properties.

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Oobleck is primarily composed of a mixture of cornstarch (amylose) and water. Cornstarch is a type of polysaccharide consisting of fine dust particles that, when mixed with water, produce a unique consistency. The most intriguing property of Oobleck is the change in its fluidity in response to applied force. While typical liquids exhibit constant fluidity, Oobleck, as a non-Newtonian fluid, can alter its flow behavior depending on the magnitude of the applied force. These types of fluids change their behavior through the strengthening or loosening of bonds between molecules.

Oobleck’s ability to behave like a liquid under normal conditions but transform into a solid when subjected to rapid pressure carries significant to understand implications in terms of importance. Water-like liquids have weak intermolecular bonds, which is why they remain in liquid form under all conditions. In contrast, in Oobleck, cornstarch particles form a solid-like structure when mixed with water, and the bonds between particles tighten under applied pressure. This demonstrates Oobleck’s transitional behavior between liquid and solid states.

The primary reason Oobleck is classified as a "non-Newtonian fluid" is that it does not conform to the fundamental laws Newton defined for liquids. Newton proposed that a liquid’s viscosity—that is, its flow characteristic—is constant and changes only with temperature, not with applied force. However, in non-Newtonian fluids, this relationship is different.

Non-Newtonian fluids such as Oobleck exhibit a behavior known as shear thickening. This means that when an external force is applied, the fluid becomes thicker and its fluidity decreases. This occurs because the bonds between molecules become tighter. On the other hand, some non-Newtonian fluids display shear thinning behavior, in which their fluidity increases when external force is applied. These behaviors reflect how molecules or particles within the fluid interact with each other and respond to external forces.

Oobleck can be made using a simple mixture of materials:

Materials:

• 2 cups of cornstarch
• 1 cup of water
• A mixing container

Procedure:

1. Place the cornstarch into the mixing container.
2. Slowly add water while stirring.
3. Continue adding water or extra cornstarch until the desired consistency is achieved.
4. Test the consistency; when it is correct, your Oobleck is ready!

To observe Oobleck’s entertaining property, gently touch the mixture to see it behave like a liquid, then press quickly to see it solidify. When pressed rapidly, Oobleck hardens, allowing you to visually experience how the material responds to applied force.

Non-Newtonian fluids like Oobleck are used not only for entertaining experiments to do but also in numerous industrial and biological applications. One of the most well-known uses of such fluids is in shock absorber systems. Non-Newtonian fluids can serve as vibration dampeners in vehicles and machinery because their response to external forces is controllable and they effectively reduce vibrations.

In addition, research in the field of biomedical engineering explores the use of these fluids. The ability of non-Newtonian fluids to blood flow in imitation ways can be used to study and simulate blood flow in veins and arteries. Furthermore, technologies based on these fluids have been developed for use in medical devices and drug delivery systems.