Sticky water

Sticky Water

By Lim Hur (20)5L

Gravity

Gravity pulling water down

Water defying gravity

What makes water so sticky?

Adhesion keeps the water stuck to the stringCohesion keeps the water stuck to itselfTogether, these two forces keep the water

flowing in a stream stuck to the string

Stick to itself force=cohesion

Stick to other things force=adhesion

Cohesion

Negative Charge

Positive Charge

Water Molecule

Hydrogen Bonding

Adhesion

Negative Charge

Positive Charge

Water Molecule

What if…

A) I use strings of 60cm and 90cm length for the experiment?

Experimental Procedures A) 1. Fill the pitcher half full with water. Add a few

drops of food colouring to make it more visible as it moves down the string.

2. Soak a length of 60cm and 90cm cotton string in water thoroughly.

3. Tie one end to the pitcher and stretch it tightly across the pouring spout.

4. With one hand, hold the pitcher by the handle about 30cm above and 60cm or 90cm away from the pitcher. Hold the string against the inside of the glass with the other hand.

5. Slowly pour the water down the string.

60cm distance between pitcher and glass

MVI_8306_FIX.MPG

90cm distance between pitcher and glass

What if…

B) What if I use strings of the same length, but have different diameters of 10mm and 18mm for the experiment?

Experimental Procedures

B) Repeat the steps in (A), this time using strings of 10mm and 18mm diameter instead.

String of

10mm diameter

String of

18mm diameter

Table of resultsString used to connect pitcher

to glass

If the water flowed from the pitcher to the glass

1st attempt

2nd

attempt3rd

attempt

Yes Yes Yes

Yes Yes Yes

Yes Yes Yes

Yes Yes Yes

String used to connect pitcher to

glassString of 60cm length

String of 90cm length

String of 10mm diameter

String of 18mm diameter

ConclusionCohesive forces are apparent between like

molecules. For instance, once the string is wet in

the experiment, the water can cling to the

already present water molecules and slide down

the string to the glass.

Likewise, adhesive forces are present in this

experiment. The water molecules are attracted

to the string molecules.

Hence, cohesion and adhesion can work together

in different length or thickness of string.

THEEND

Q & A