On a Roll

Before the meeting:

1. Identify a flat area to set up the demonstration. Place the plywood against the seat of the chair, placing the brick at the bottom of the plywood to keep it in place, making a ramp for the balls to roll down.

During the meeting:

1. Gather the Cub Scouts and adult partners and inform them that in this activity they are going to explore the property of motion. Motion is simply when something moves. They are going to watch what happens when we roll different-sized balls down this ramp.
2. Inform the den that there are four different balls and ask them which ball they think will go down the ramp the fastest and why.
3. Roll each ball down one by one.
4. See who was right. Ask the den what is making the balls move? Gravity
5. Gravity is a force that pushes down on everything. One thing that can change how gravity pushes on something is it’s mass. Mass the amount of substance in something. The soccer ball has a lot of air in it and air is not made up of much. However, the softball has a hard center, so the softball has more mass then the soccer ball that is why it rolls faster.
6. Tell the den that we can figure out the mass of something by the way gravity effects it or in this activity by how fast it rolls down the ramp.
7. Rolls the balls down again and see if the den can place the different balls by their mass which is the same as how fast they roll down the ramp.
8. Ask the Cub Scouts what type of ball would have a lot of mass?
   • Bowling ball
   • Golf ball
   • Cannon ball