# Rank It Up!

## Problem

My problem is that at which temperature is the water surface tension more. I want to know if different temperatures will affect surface tension.

## Hypothesis

I think the surface tension wil be affected by temperature, because the particles will be change when heated or freezes. I think cold water will have the most surface tension because the colder the more calmer and slower the particles move.When it will become hotter, the surface tension might decrease, since how fast the particles might move.

## Materials

-2 sponges

-Scissors

-Metric Ruler

-Transperencies

-A marker

-1 box of toothpicks

-Tape

-Large sink

-Water

-Thermometer

-Eye dropper

-Laundry detergent

-Lab notebook

-Pencil

## Procedure

1.Cut the sponge into 10 small pieces.(about 1.5 by 1.5)

2.Draw a shape for the raft on the transparency. The raft should be symmetric.(7-30 cm and about half that for the width.)

3. Cut out a space on the back of the raft where the sponge will be(about 3 by 4 cm).

4.Cut out the raft.

5.run the toothpick through one of the sponge pieces.

6.Attach the 2 toothpick sides to the raft.

7.Fill the large sink with water at room temperature.

8.Put the raft onto the the water surface and let it float.

9.Put a drop of laundry detergent to the sponge.

10.observe and record motion.

11.Repeat the process for hot water and for cold water.

12. Clean up materials.

## Conclusion

In conclusion my hypothesis was correct. I found out that temperature does affect surface tension. You can see that in results as the raft does sink in the hot water(not completely sunk)but in cold water it stays completely still and afloat.At room temperature it was afloat but tiny parts of the raft was a little bit sunk and in the water.

## Before Experiment Research

Q:What is the difference between solid and liquid surface tension?

Research: The surface tension of a liquid results from an imbalance of intermolecular

Attractive forces, which is the cohesive forces between the molecules.

Cohesive forces: Intermolecular forces which cause a tendency in liquids to resist seperation

The surface tension of a solid can't be measured like a liquid's surface tension can be.

Forces of the attraction between liquid and solid tensions are called adhesive forces. The difference in strength between cohesive forces and adhesive forces show the behavior between a liquid with a solid.

## After Experiment Research

Surface tension decreases when thermal energy increases. Cohesive forces decrease when thermal particle activity increases.

Do different liquids have different surface tension: Yes they do because they have different amounts of intermolecular forces.

In water there are two types of molecules: the interior molecule and the exterior molecule. The interior molecule is attracted to the molecules all around it. The exterior molecule is attracted to the surface molecules and the ones underneath. The water molecules attract each other due to the water's polar property. The positive ends of hydrogen and the negative ends of oxygen cause if to stick together. This is how surface tension came to be.

## Variables

Independent Variable- The different points of temperature.

Dependent Variable- The force of the surface tension on the raft

Controlled Variables-The type of liquid(water), the area of the sink, the amount of water, the same raft.