Mystery of dilatancy Rinto Takashima Yuki Kato About

Mystery of dilatancy ２－１ Rinto Takashima Yuki Kato

About our research motive Our teacher showed us dilatancy in our class, so we wanted to know Why the dilatancy phenomenon occurs? ? How it is used in our lives? ?

What is the dilatancy phenomenon? ? A special movement of a mixture(powder and water) Ｄｉｌａｔａｎｃｙ ｐｈｅｎｏｍｅｎｏｎ!! Press with great force, it becomes like a solid matter. Press with little force, it stays like a liquid matter.

Experiment 1 Try to make dilatancy and search the best conditions of powder and liquid. Experimental method 1. Measure the amount of water and starch. 2. Mix water and starch. 3. check if the dilatancy phenomenon is occurred or not.

Results of experiment 1 Liquid(water) Powder(starch) 100 g × 100 g 125 g △ 100 g 130 g ○ 100 g 135 g ◎ 100 g 140 g △ 100 g 150 g △ 100 g 200 g ×

Experiment 2 See the size and shape of starch’s grains with the microscope. And find the best size and shape.

The characteristics of starch The size is about 0. 06 mm. The shape has roundish. Dilatancy phenomenon happens. However… we can’t find some important characteristics only with starch.

Additional experiment See the size and shape of flour grains with a microscope. Find differences between starch and flour. Try to make dilatant fluid with flour. However, dilatancy phenomenon didn’t happen!!

Some pictures of powders (starch and flour) Starch Flour

Results of experimental 2 Starch Flour The size is about 0. 06 mm. The size is about 0. 03 mm. The shape has roundish. The shape is angular. Dilatacy phenomenon happens. Dilatancy phenomenon doesn’t happen. The best shape is round. But we couldn’t find the best size…

Examination of our research The best combination is 27 : 20 ( powder : water) Dilatancy phenomenon occurs with “starch” not with “flour”. The best shape is round. However, the best size isn’t well known.

Let’s try dilatancy phenomenon!!

Further Research More experiments (using more kinds of powder and changing the solvent) are required!! Search the relationship between liquefaction phenomenon and dilatancy.