This document describes an experiment investigating the forces of cohesion and adhesion that allow water to flow in a stream down a string. The experiment involves using strings of different lengths and diameters suspended between a pitcher of water and a glass. It is observed that water is able to flow down the string due to the combined effects of cohesion, which causes water molecules to stick to each other, and adhesion, which causes water molecules to stick to the string. The conclusion is that cohesion and adhesion can work together to allow water to flow down strings of varying lengths and thicknesses.

1. Sticky Water By Lim Hur (20) 5L

2. Gravity

3. Gravity pulling water down

5. Water defying gravity

6. What makes water so sticky? Adhesion keeps the water stuck to the string Cohesion keeps the water stuck to itself Together, 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

7. Cohesion Negative Charge Positive Charge Water Molecule

8. Hydrogen Bonding

9. Adhesion Negative Charge Positive Charge Water Molecule

10. What if… A) I use strings of 60cm and 90cm length for the experiment?

11. 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.

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

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

14. 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.

15. 60cm distance between pitcher and glass

16. 90cm distance between pitcher and glass

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

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

19. String of 10mm diameter

20. String of 18mm diameter

21. Table of results If the water flowed from the pitcher to the glass

22. Conclusion Cohesive 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.

23. THE END

24. Q & A