Hypothesis   I will be conducting an experiment on the surface tension of water using a paperclip. I chose this topic because I have always been fascinated by how water striders can stay afloat and not sink while walking on water. I wondered how they can pull off this feat.   Set up #1: I think it will sink immediately.   Set up #2: I think it will float.   Set up #3: I think it will start off floating and once we add the dish soap it will sink.

Research

surface tension, property of a liquid surface displayed by its acting as if it were a stretched elastic membrane. This phenomenon can be observed in the nearly spherical shape of small drops of liquids and of soap bubbles. Because of this property, certain insects can stand on the surface of water. An increase in temperature lowers the net force of attraction among molecules and hence decreases surface tension. Surface tension | Definition, Examples, & Facts | Britannica   Water striders are about a half inch long with a thin body and three sets of legs. The water strider's secret is its legs. The legs have tiny hairs that repel water and capture air. By repelling water, the tiny water striders stand on the water’s surface and the captured airs allows them to float and move easily. The water strider's shorter front legs are used for catching and holding onto food. Water striders eat insects and larvae on the surface of water, such as mosquitoes and fallen dragonflies.   With a little thing we scientists call SURFACE TENSION. Basically it means that there is a sort of skin on the surface of water where the water molecules hold on tight together. If the conditions are right, they can hold tight enough to support your paper clip. The paperclip is not truly floating; it is being held up by the surface tension. Many insects, such as water striders, use this “skin” to walk across the surface of a stream. Bing Videoshttps://sciencebob.com/make-a-paperclip-float/#google_vignette

Variables

Manipulated Variables: My manipulated variables will be what type of paper clip set up, each one will have:

Set Up #1: Plastic-coated metal paperclip by itself carefully set on the water.

Set Up #2:  Plastic-coated paperclip set on top of 1.5” x 1.5” piece of paper towel on top of the water.

Set Up #3: Plastic-coated paperclip that is already floating from Set Up #2, add 3 drops of dish soap to the water.   Responding Variable: My responding variables will be weather the paperclip will float or sink in each of the three set ups.     Controlled Variables: ·      3 cups of room temperature water (21 Degrees Celsius) ·      1 glass bowl ·      1 plastic coated metal paperclip

I chose to use room temperature water as it was the easiest temperature to maintain. Also, because hot water decreases the surface tension and it may not work as well. I chose to use a glass bowl so I can easily see if the paperclip is floating or not. I chose a paperclip because it is light weight, and through my research I learned that it only floats sometimes.

Procedure   Steps for surface tension experiment:

1.     Clean the area that experiment will happen in.

2.     Get the glass bowl, measuring cup, paper clip, Dawn brand dish soap, logbook with chart in it, pencil, eraser and laptop for note taking.

3.     Cut 5 cm x 5 cm square of paper towel. Set aside.

4.     Using the measuring cup get 500 milliliters of water in the clear glass bowl.

5.     Cover water leave sitting until room temperature (21°C.) Set Up #1: 6.     Keeping the paper clip horizontal lower onto the surface of the water.

7.     Observe what happens and record in logbook.

8.     Using clean hands remove the paper clip from the glass bowl.

Set Up #2: 9.     Put the paper clip in the middle of the 5 cm x 5 cm square of paper towel keeping everything flat.

10.    Carefully lower using sides of paper towel onto the surface of the water.

11.    Wait for paper towel to sink.

12.    Pull paper towel out with toothpick.

13.    Observe and record in logbook.

Set Up #3: 14.    Leaving the paper clip floating used 3 drops of liquid dish soap.

15.    Observe what happens record it in your logbook.

16.    Clean up materials and workspace.

17.    Repeat experiment at least three times to make sure results are consistent.

| Trial #1
Jan. 24th, 2026 | Paperclip Only | Paperclip & Paper Towel | Floating Paperclip & Dish Soap | | ------------------------- | ---------------- | ------------------------- | -------------------------------- | | Float |   | · Gently lowered paperclip and paper towel in together.
· Both paperclip and paper towel floated.
· Removed paper towel with toothpick.
· Paperclip continued to float. |   | | Sink | · It immediately sank |   | · Paperclip sank to the bottom as soon as dish soap was added. |

| Trial #2
Jan. 24th, 2026 | Paperclip Only | Paperclip & Paper Towel | Floating Paperclip & Dish Soap | | ------------------------- | ---------------- | ------------------------- | -------------------------------- | | Float | · Accidentally dropped paperclip onto the surface of the water a few mm away.
· Paperclip floated. | · Gently lowered paperclip and paper towel in together.
· Both paperclip and paper towel floated.
· Removed paper towel with toothpick.
· Paperclip continued to float. |   | | Sink |   |   | · Paperclip sank to the bottom as soon as dish soap was added. |

| Trial #3
Jan. 25th, 2026 | Paperclip Only | Paperclip & Paper Towel | Floating Paperclip & Dish Soap | | ------------------------- | ---------------- | ------------------------- | -------------------------------- | | Float |   | · Gently lowered paperclip and paper towel in together.
· Both paperclip and paper towel floated.
· Removed paper towel with toothpick.
· Paperclip continued to float. | · After 3 drops of dish soap, the paperclip was still floating.
· Added several squirts of dish soap.
· Paperclip still floated.
· Prodded the water around the paperclip with a toothpick.
· Still floated
· Pocked the actual paperclip with toothpick and it then sank. | | Sink | · It immediately sank |   |   |

| Trial #4
Feb. 3rd, 2026 | Paperclip Only | Paperclip & Paper Towel | Floating Paperclip & Dish Soap | | ------------------------- | ---------------- | ------------------------- | -------------------------------- | | Float | · It floated | · Gently lowered paperclip and paper towel in together.
· Both paperclip and paper towel floated.
· Removed paper towel with toothpick.
· Paperclip continued to float. | · Paperclip was to the side of bowl. Dish soap added to other side, and it continued to float with quite a bit of dish soap added.  | | Sink |   |   |   |

| Trial #5
Feb. 3rd, 2026 | Paperclip Only | Paperclip & Paper Towel | Floating Paperclip & Dish Soap | | ------------------------ | ---------------- | ------------------------- | -------------------------------- | | Float | · It floated | · Gently lowered paperclip and paper towel in together.
· Both paperclip and paper towel floated.
· Removed paper towel with toothpick.
· Paperclip continued to float. |   | | Sink |   |   | · Paperclip was more in the middle of the bowl. It sank upon adding the 3 drops of dish soap.   |

| Trial #6
Feb. 8th, 2026 | Paperclip Only | Paperclip & Paper Towel | Floating Paperclip & Dish Soap | | ------------------------ | ---------------- | ------------------------- | -------------------------------- | | Float |   | · Gently lowered paperclip and paper towel in together.
· Both paperclip and paper towel floated.
· Removed paper towel with toothpick.
· Paperclip continued to float. |   | | Sink | · It immediately sank |   | · Paperclip was more in the middle of the bowl. It sank upon adding the 3 drops of dish soap.   |

| Trial #7
Feb. 8th, 2026 | Paperclip Only | Paperclip & Paper Towel | Floating Paperclip & Dish Soap | | ------------------------ | ---------------- | ------------------------- | -------------------------------- | | Float | · It floated | · Gently lowered paperclip and paper towel in together.
· Both paperclip and paper towel floated.
· Removed paper towel with toothpick.
· Paperclip continued to float. |   | | Sink |   |   | · Paperclip was more in the middle of the bowl. It sank upon adding the 3 drops of dish soap.   |

| Trial #8
Feb. 9th, 2026 | Paperclip Only | Paperclip & Paper Towel | Floating Paperclip & Dish Soap | | ------------------------ | ---------------- | ------------------------- | -------------------------------- | | Float | · It floated | · Gently lowered paperclip and paper towel in together.
· Both paperclip and paper towel floated.
· Removed paper towel with toothpick.
· Paperclip continued to float. |   | | Sink |   |   | · Paperclip was more in the middle of the bowl. It sank upon adding the 3 drops of dish soap.   | | Trial #9
Feb. 9th, 2026 | Paperclip Only | Paperclip & Paper Towel | Floating Paperclip & Dish Soap | | Float | · It floated | · Gently lowered paperclip and paper towel in together.
· Both paperclip and paper towel floated.
· Removed paper towel with toothpick.
· Paperclip continued to float. | · Paperclip was to the side of bowl. Dish soap added to other side, and it continued to float with quite a bit of dish soap added.  | | Sink |   |   |   |

| Trial #10
Feb. 9th, 2026 | Paperclip Only | Paperclip & Paper Towel | Floating Paperclip & Dish Soap | | ------------------------- | ---------------- | ------------------------- | -------------------------------- | | Float |   | · Gently lowered paperclip and paper towel in together.
· Both paperclip and paper towel floated.
· Removed paper towel with toothpick.
· Paperclip continued to float. |   | | Sink | · It immediately sank |   | · Paperclip was more in the middle of the bowl. It sank upon adding the 3 drops of dish soap.   |

I was surprised that the paper clip on its own in Setup #1 floated most of the time. I thought it would sink all the time because it didn't trap enough air under it to float. Setup #2 was not surprising from the results since the paper towel would trap air underneath it helping to keep the paper clip afloat. For Setup #3 the dish soap made it sink most of the time but there were a few exceptions where the paper clip was close to the side and the dish soap didn't have much effect on it but overall, the paperclips sank when the dish soap was added.

See the attached graphs showing Setup #1, Setup #2, Setup #3.

I did a couple of extra tests to see if I could get the paperclip on the paper towel to sink. Here are my observations:

| Additional Testing: #1
Feb. 3rd, 2026 | Dish Soap Already in Water. Add Paperclip & Paper Towel | | ---------------------------------------- | --------------------------------------------------------- | | Float |   | | Sink | · It sank! Both the paper towel and the paperclip! |

| Additional Testing: #2
Feb. 3rd, 2026 | Dish Soap Already in Water. Add Paperclip & Paper Towel | | ---------------------------------------- | --------------------------------------------------------- | | Float |   | | Sink | · It sank this time too! Both the paper towel and the paperclip! |

Conclusions   I set out to discover how water striders can stay afloat. I think that I picked a good way to figure it out. My hypothesis for set up #1 was that I thought it would sink immediately and I was mostly correct. Most of them sunk, but a few floated. The ones that sunk I was pretty sure when I lowered the paper clip in, my fingers broke the surface tension. The ones that floated, was because they were accidentally dropped in and my fingers did not break the surface tension first.

My hypothesis for set up #2 was that the paperclip would float. This was correct on all 10 trials.

My hypothesis for set up #3 was that they would all sink. This was mostly true, but a few remained floating after the dish soap was added. Why? I think that the dish soap was too far away from the paperclip.

In conclusion, if something breaks or changes the surface tension, like fingers or dish soap, the paperclip (or water strider) will sink.

Applications

I did my project studying surface tension. Why that was a useful choice is because it gives us a better understanding of how insects can walk on water and we cannot. I think this information would be useful because what if in the future water striders cannot stay up on top of the water and drown. Scientists can use this data to discover why the water striders can’t float anymore and then test the water to see if there’s chemicals like bleach or the stuff in dish soap in the water and possibly save the Water Striders from extinction.

Sources of Error

Some trials may have been a little inaccurate because for the first set up I accidentally dropped some of the paperclips in, instead of putting them in, making them float. I only dropped them by a few millimeters, but that may have affected the results. For the second set up everything went according to plan so nothing was inaccurate. The third set up was a bit interesting, you had to pour the dish soap pretty close to the paper clip and the paper clip had to be in the middle of the bowl for it to sink. Otherwise the paper clip would not sink and the dish soap would just sink to the bottom.

Information Sources:

https://www.britannica.com/science/surface-tension

https://sciencebob.com/make-a-paperclip-float/#google_vignette

https://learning-center.homesciencetools.com/article/experiments-with-water-science-project/

Acknowledgement

I'd like to thank my mom who was a massive help on this part of the project. She believed in me even when I didn't believe in myself.