FORCES

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**//GRAVITY//****:** Force of attraction between objects. Earth has gravity but gravity is the force of attraction between any two objects. In Outer Space it is weak. [] [] [|http://videos.howstuffworks.com/science/gravity-videos-playlist.htm#video-28750]

**//FRICTION://** A force called friction usually hinders the motion of moving objects. []

Testing friction by: Saxon

We want to find out what surface at school has the most friction.

So that this investigation is a fair test we are keeping these things the same: The gradient, the force, the marble and our measuring device.

We will only change the friction/ surface.

<span style="background-color: #800080; color: #ffffff; display: block; font-family: 'comic sans ms',cursive; font-size: 130%; text-align: center;">We need this equipment: <span style="background-color: #800080; color: #ffffff; display: block; font-family: 'comic sans ms',cursive; font-size: 130%; text-align: center;">Marble <span style="background-color: #800080; color: #ffffff; display: block; font-family: 'comic sans ms',cursive; font-size: 130%; text-align: center;">Meter ruler <span style="background-color: #800080; color: #ffffff; display: block; font-family: 'comic sans ms',cursive; font-size: 130%; text-align: center;">Different surfaces <span style="background-color: #800080; color: #ffffff; display: block; font-family: 'comic sans ms',cursive; font-size: 130%; text-align: center;">Pencil and topic book

<span style="background-color: #800080; color: #ffffff; display: block; font-family: 'comic sans ms',cursive; font-size: 130%; text-align: center;">We will use this method: <span style="background-color: #800080; color: #ffffff; display: block; font-family: 'comic sans ms',cursive; font-size: 130%; text-align: center;">First, we find a surface to test. Check if the surface is flat. You can do this by putting the marble on the ground. <span style="background-color: #800080; color: #ffffff; display: block; font-family: 'comic sans ms',cursive; font-size: 130%; text-align: center;">If it rolls away it is not a flat surface. Then flick the marble. Mark where it starts and stops with a piece of grass or marker. Record the distance the marble travels in cm or mm.

<span style="background-color: #800080; color: #ffffff; display: block; font-family: 'comic sans ms',cursive; font-size: 130%; text-align: center;">We predict that the marble will travel a longer distance on a surface that has only a little friction.



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