Hi! My name is Keith and I'm 10 and in the fourth grade in Kansas. This is my science fair project. My dad helped me put it on the Internet so my grandma in Arizona can see it. The science fair is Friday, March 6 in our school gym!

We have to use the scientific method, so my page goes in order just like my board does: question, hypothesis, materials, procedure, data, conclusion.

[ Question | Hypothesis | Materials | Procedure | Data | Conclusion | What Went Wrong ]

Which brand of paper towel is the strongest when it's wet?

I thought of this when I spilled a whole glass of grape juice and the paper towel ripped and my mom had to get the mop. I wanted to know if some kinds are really stronger or if they're all the same.

I tested five brands. Mrs. Clouse said we can't put the real names of things on our boards, so they are Brand A, Brand B, Brand C, Brand D and Brand E. (My dad wrote down which is which and taped it on the back of my board.)

I think Brand B will be the strongest because it is the thickest and it costs the most. I think Brand E will be the weakest because it is the cheapest one and you can almost see through it.

• 5 rolls of paper towels (Brand A to E)
• A LOT of pennies (my dad's penny jar had 312)
• An embroidery hoop from my mom's sewing basket
• A tablespoon for measuring
• Water
• A big mixing bowl
• Two stacks of books the same height
• A watch with a second hand
• My science notebook and a pencil

1. Tear off one sheet of paper towel and stretch it tight in the embroidery hoop.
2. Put the hoop across the two stacks of books with the bowl underneath.
3. Pour 2 tablespoons of water in the middle of the paper towel, slowly.
4. Wait 30 seconds so the water soaks in.
5. Put pennies on the middle of the towel one at a time until it rips and they fall in the bowl.
6. Count how many pennies it held before it ripped. (The one that broke it doesn't count.)
7. Do it 3 times for each brand. That's called trials.

Things I kept the same every time (Mrs. Clouse says these are controlled variables): the same hoop, the same amount of water, the same 30 seconds, the same kind of pennies, and me putting them on every time so it's the same hand.

The thing I changed: the brand of paper towel.

Here is how many pennies each wet paper towel held before it ripped.

* Something went wrong on this one. See What Went Wrong. If you leave out trial 2, Brand C's average is 62.5.

My bar graph (each square is 10 pennies, rounded. I used 62.5 for Brand C):

A
B
C
D
E
	10	20	30	40	50	60	70	80	90	100

My hypothesis was right! Brand B was the strongest. It held 99 pennies on average, which is about twice as many as Brand A. Brand E was the weakest, like I thought. It only held 33.

From strongest to weakest: B, D, C, A, E. (That's using 62.5 for Brand C.)

I noticed that the thick, puffy kind held the most and the thin kind held the least. Brands A and C came out with exactly the same average, 49, but only because of Brand C's bad trial. Without it, C beats A.

What this means in real life: If you spill a big glass of grape juice, use Brand B. If you just need to wipe your hands, Brand E is fine and it costs less.

I also learned that you need to do more than one trial, because one bad trial can mess everything up.

Trial 2 of Brand C only held 22 pennies. I think I poured the water too fast and it all went in one spot and made it soggy right in the middle, so it ripped way early. Mrs. Clouse said that in real science you don't just erase it, you keep it and explain what happened. So it's still in my data with a star.

Also, my cat jumped on the table during Brand D, but I started that one over, so it doesn't count.