# The Effect of Surface Texture

## Which ramp surface will a marble roll the farthest on?

The purpose of this experiment is to find out whether the texture of a surface will affect the distance rolled by a marble, and if so, which ramp surface a marble will roll the farthest on.

Hypotheses

1. That the surface texture of an inclined plane will affect the distance traveled by a marble rolled down it.
2. That the less textured the ramp's surface is, the farther the marble will roll.

Prediction

I think the marble will roll best down the foil because it is smooth and it will roll least on the towel because it is textured.

### Materials

• Wooden ramp with beveled end and a channel down the center
• 1 marble
• Lengths of textured fabric, cut to fit the ramp (cloth towel, paper towel, foil, sandpaper, wax paper, cling wrap, foam)
• Red, yellow, and green masking tape
• Permanent marker
• 50' measuring tape
1. Locate a large level surface on which to perform the experiment.
2. Place the ramp on the floor and mark where it is to ensure it has the same starting point for all rolls.
3. Hold the marble at the top of the ramp and release it.
4. When the marble comes to a stop, mark its position with a piece of red tape labeled "wood 1."
5. Repeat Step 3 and mark the marble's stopping position with yellow tape labeled "wood 2."
6. Repeat Step 3 and mark the marble's stopping position with a piece of green tape labeled "wood 3."
7. Cover the ramp with the towel and repeat Steps 3-6, labeling the tape "towel."
8. Repeat Step 7 for the sandpaper, wax paper, paper towel, cling wrap, foam and foil, marking the name of each covering on the different colored tapes.
9. Measure from the base of the ramp to each piece of tape and record the measurements for the first, second, and third rolls on each surface.
10. Calculate the average distance rolled for each surface and graph the results.

### Observations

Table 1: Distance rolled by surface

Roll 1
Roll 2
Roll 3
Spare Roll
Average
Towel
192"
199"
196"

195.6"
S/paper
272"
264"
271"

269"
Paper towel
298"
300"
301"

299"
Cling Wrap*
284"
306"
316"

301"

307"
Waxpaper
323"
312"
307"

310"
Foam
319"
316"
314"

316.3"
Foil
313"
328"
316"

319"
Wood
336"
322"
326"

328"

* Average calculated on rolls 2, 3 and spare roll

My two hypotheses suggested that the surface texture of an inclined ramp would affect the distance traveled by a marble rolled down it, and that the less textured the ramp's surface was the farther the marble would roll. My experiment proved both of these hypotheses to be correct. The strongest evidence for this can be found in the results for the towel and the sandpaper. The towel was the most textured surface and it had the shortest roll. It only rolled an average of 195.6 inches, which was 73.4 inches less than the sandpaper roll and 114.4 inches less than the paper towel roll.

I think the wood roll was the best because it was naturally smooth. All the other surfaces, which were laid on top of the wood, had slight ripples or air bubbles below them which probably slowed the marble down.

I made an interesting observation when I rolled the marble down the cling wrap. The first roll didn't go as far as the other rolls. I thought maybe it happened because there was a static charge and it slowed the marble down. I repeated the three rolls with a new piece of cling wrap and the same thing happened, which suggests my theory was correct. I therefore disregarded the first roll (284 inches) and rolled the marble a fourth time and then calculated the average for rolls two, three, and four.

One uncontrolled variable in my experiment was the floor because it wasn't exactly level. Sometimes near the end of a roll the marble would roll sharply to the side or stop and roll backwards. To make my measurements relatively accurate I marked where the marble stopped rolling forward. The ability to replicate my results would be affected by the floor used.

### How does it work?

Discussion:
Galileo Galilee once did an experiment by rolling different weighted balls down an inclined plane and proved that objects fall at the same speed no matter what they weigh. I explored further into this principle by rolling a ball down an inclined plane covered with different textures to see if texture affects the distance traveled by an object.

My hypotheses were supported by Newton's Second Law, which states if a moving object is acted upon by a force it will change its speed in proportion. In my experiment this force was the friction caused by the texture of the ramp. This caused the marble to slow down when the more textured surfaces created more friction. This type of friction is called rolling friction. Rolling friction is affected by the texture of both the surface and the rolling object. Had I used a tennis ball it probably would have rolled a shorter distance because of the ball's texture. Rolling friction is also affected by how large the contact area is between the object and the surface. If my marble was shaped into a cylinder there would be more contact area between the surfaces and so there would be more rolling friction.

Potential and kinetic energy were not variables in this experiment because the ramp's height and length did not change and neither did the marble's shape, size or texture.

Conclusion: The marble rolled farther on smoother textures, with texture clearly affecting the distance traveled. This proved both my hypotheses to be correct. The distance traveled was a result of the amount of rolling friction present which was determined by the ramp's texture. My prediction of the results was accurate except the wood roll was farther than the foil roll.

Science Fair Connection:

The Effect of Surface Texture is an outstanding science fair project. It carefully controls the variables (the things that change in the experiment) by only changing one thing at a time. The starting point is always the same. The angle of the ramp is consistent. The same marble is used. The floor remains the same. Only the surface texture of the ramp changes.

This would be a great science fair project for you to try, too. Do you think you'd get the same results? Here are some other variables you might want to test to make the experiment your own:

• Choose different surface textures than in the previous experiment. What effect do they have on the distance the marble travels?
• Keep the surface texture the same, but change the size of the marble. Does the size of the marble affect the distance it travels?
• What would happen if you used a Matchbox car instead of a marble but kept everything else the same?
• Change the shape of the object you roll down the ramp but keep everything else the same. What do you discover about the shape or surface area of an object and its effect on friction and distance traveled?

The Effect of Surface Texture is an engaging experiment that clearly shows the scientific method in action!

 Brilliant! Daisy    -  April 17, 2012 This user gave 5/5 stars This is just what I needed to know! I couldn't find anything like this anywhere, even after searching for ages. This is a really big help, and has everything I needed to know - perfect little experiment, thanks.

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