Does Surface Area Effect Cohesion and Adhesion On Water?

Conclusion

How does it work?

A force called cohesion, which is the attraction of molecules that are the same to each other, causes this effect. The surface tension “membrane” is always trying to contract, which explains why falling droplets of water are spherical or ball shaped. The water stays in the bottle even though the card is removed because the molecules of water are joined together to form a thin membrane between each opening in the screen. Tipping the bottle or touching the screen will break the surface tension!

Science Experiment:

Cohesive and Adhesive Forces

My Experiment

Water also has a high level of surface tension. This means that the molecules on the surface of the water are not surrounded by similar molecules on all sides, so they're being pulled only by cohesion from other molecules deep inside. These molecules cohere to each other strongly but adhere to the other medium weakly. One example of this is the way that water beads up on waxy surfaces, such as leaves or waxed cars. Surface tension makes these water drops round so they cover the smallest possible surface area. (1)Cohesion allows for the development of surface tension, the capacity of a substance to withstand being ruptured when placed under tension or stress.

(1)-http://science.howstuffworks.com/environmental/earth/geophysics/h2o7.htm-08/06/14

My Experiment

Research

The hydrogen bond between water molecules that we talked about in the first section is the reason behind two of water's unique properties: cohesion and adhesion. Cohesion refers to the fact that water sticks to itself very easily. Adhesion means that water also sticks very well to other things, which is why it spreads out in a thin film on certain surfaces, like glass. When water comes into contact with these surfaces, the adhesive forces are stronger than the cohesive forces. Instead of sticking together in a ball, it spreads out. (1)

My Experiment

Method

• Cut a piece of mesh from the bag large enough to hang over the mouth of the bottle.
• Stretch the mesh over the bottle and use a rubber band to secure it in place.
• Fill the bottle with water by pouring the water through the screen. Fill the bottle almost to the very top.
• Cover the bottle with you hand. Hold your hand in place as you turn the card and the bottle upside down. Slowly remove you hand from the opening and the water mysteriously stays in the bottle.
• Tip the bottle slightly to the left or right and the water will fall. Shake the bottle and the water will fall. Touch the screen and the water will fall.

My Experiment

Materials:

• Plastic mesh
• Wide mouth bottle
• Rubber band
• Pitcher of water
• Bucket to catch the falling water

Variables:

Dependent- The amount of water fallen out of the full bottle of water.

Independent-The type of mesh used.

Controlled-The amount of water in the bottle

Prediction:

I think a smaller mesh will remain full and the larger holed mesh will lose water because the smaller holed mesh has more surface area.

What am I testing for:

I am testing if the size of mesh affects the cohesion and adhesion forces acting on the water.

Medium Sized

Small Sized

Big Sized

the affect Cohesion and Adhesion On Water?

Results

According to the graph my prediction was right; no water was displaced with the smaller holed mesh but the larger holed mesh had lost 37ml of water and the medium sized mesh lost 17ml of water

Results