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Marshmallows making funny faces science experiment – demonstrate the principle of pressure.

Colored Marshmallows

Marshmallows making funny faces

With this experiment we’ll cause marshmallows to make funny faces and demonstrate a scien-terrific principle called pressure.

  1. Draw a face on both ends of a large marshmallow (the flat end). Draw ’em to look like your friends if possible!
  2. Drop the marshmallow into a glass bottle. You’ll have to make sure and use a bottle that has an opening slightly larger than the marshmallow.
  3. Take the straw and wrap the clay about 1 inch from the end in such a manner that the clay forms a ‘ring’ around the straw. Place the short end of the straw into the bottle. The clay should stop the straw from dropping all the way into the bottle. Now press the clay around the mouth of the bottle so that the bottle is completely sealed, and no air can get in (or out).
  4. Stand in front of a mirror so you can see the face on the marshmallow. Suck air out of the bottle. Make sure there are not leaks in the clay.

Yeah! Pretty funny huh? Now stop sucking on the straw. What happens to the marshmallow then?

Although a marshmallow appears to be solid it is actually filled with many pockets. These pockets are filled with air (much like a sponge). When you suck the air out of the bottle you are decreasing the pressure inside the bottle, which causes the spongy solid – the marshmallow – to expand. When you stop sucking on the straw and remove the straw from your mouth the air rushes back into the bottle, increasing the pressure and causing the marshmallow to return to its original size.

Parent/Teacher/Advanced Notes

Pressure is a fundamental concept in physics that is defined as the force exerted per unit area. The principle of pressure states that the pressure exerted on the surface of a fluid or a solid is proportional to the force applied and inversely proportional to the area over which the force is applied. If a fluid, gas, or solid is exposed to suitable forces, pressure is produced in it. The greater the force, the greater the pressure.

In other words, pressure can be defined as force per unit area and calculated using the following equation:

Pressure = Force / Area

where force is measured in Newtons (N) and area is measured in square meters (m²). The unit of pressure is the Pascal (Pa) which is defined as one Newton per square meter.

The principle of pressure has many applications in physics and engineering, including fluid mechanics, aerodynamics, and hydraulics. For example, the principle of pressure is used in the design of airplane wings and the calculation of water pressure in pipes.

Experiment Supplies

Supplies: Clay, Straw, Glass bottle, Marshmallow

Image Credits

In-Article Image Credits

Colored Marshmallows via Wikimedia Commons by Andy Johnson with usage type - Public Domain. December 12, 2008

Featured Image Credit

Colored Marshmallows via Wikimedia Commons by Andy Johnson with usage type - Public Domain. December 12, 2008


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