How does the use of rollers affect the force required to move a book a given distance along a surface?

What I already know:

I already know that rollers will help move the book farther. ...Ashley

I know that there is more force needed when you have more friction on the surface your dragging on. You need more force for heavy things. Rollers help things move easier. ...Taylor

If an object weighs more, it needs more force. Friction slows things down. Rollers can make it move faster. ...Jeremy

Friction slows things down. Force is needed to move an object. You need more force on a rough surface. ...Zach

The more friction the more force you needed (more washers) for the two books on the table. And you needed less washers for the two books on the rollers. ...Malana

I found out that more washers are needed for two books than for one book. I know because I saw it happen and it took a lot of washers. We needed 29 washers to move 2 books across the table. ...Brooke So.

Experiment Data:

Moving two books on the table took 22 washers. Moving two books on the rollers took 2 washers. ...Jessie

I found out the rollers moved quickly on the straws because less force was needed. The reason I know this is I observed very carefully. ...Ashlie

Other thoughts:

Some straws were bent so they didn't work as well. ...Cameron

If the desk was sticky the books would stick to it and not move. ...Nathan

One problem was we did not space the straws very well. ...Logan

My hypothesis:

I think that rollers will decrease the amount of force needed. ...Lauren

I think rollers will help because rollers are like wheels and wheels make work easier. ...Shane

I think the rollers will decrease the amount of force needed. ...Duane

Results

The rollers made it faster. The roller is like a simple machine. ...Maeve

On the table it took 9 washers to move one book and 14 washers to move two books. On the rollers it took only two weights to move one book and 4 weights to move 2 books. ... Michael M.

The more friction there was the more weights we needed. We neede 9 weights to move one book on the table and 17 weights to move two books. It only took 5 and 6 to move them with rollers. ...Tim

The rollers are like moving with a machine because there is less friction. ...Brooke Ann

The straws moved closer together when the books moved across them. ...Alan

We put 2.5 centameters between the straws but they moved closer together. ...Zach

Science Index Page for 2003-2004

January 5, 2004