Force Vs. Surfaces

In continuing our Force and Motion Unit, first grade talked about how gravity is a force. It pulls us down to the earth. We all jumped in the air to see exactly how gravity worked. We compared it to a really strong magnet.
First grade also talked about how surfaces effect force. We did an experiment tying a string to a wood block on one end and an empty plastic cup on the other. We put the wooden block on the smooth table top and hung the cup from the end. Adding one penny at a time, we counted to see how many it would take to make the block move on the smooth surface. It took 50 pennies to make it move. Then we did the same thing again but this time with a piece of rough sandpaper under the wooden block. It took over 150 pennies to make the block move. This showed us that less force is needed to move an object on smooth surfaces then on rough ones.