Patterns of Motion & Friction

Before Video

• When someone swings, they move forward and back as well as up and down in a repeated pattern on motion. Over time, the swings become shorter and the swing eventually stops.

• The force of friction slows down a book sliding across the floor. It slows it down so much that it comes to a stop!

• When someone goes bungee jumping from a bridge, they fall down, then they move back up. Then they fall down again and back up again. The pattern keeps repeating. They continue to move up and down but in smaller and smaller amounts until they come to a stop.

• The box pushed on the ice would move further because the ice is more slippery than the cement. In more scientific terms, the force of friction between the box and the ice is less than the force of friction between the box and the cement.

After Video

• When Izzy jumps rope, he knows when to jump because the rope moves up, over, down and around him in a repeating pattern.

• We can predict that a ball thrown straight up will fall straight down again because we have likely done it before and noticed a pattern that happens every time.

• The longer the string length, the slower a pendulum swings. The shorter the string length, the faster a pendulum swings.

• No. The difference we see in Izzy's and Zoe's pendulums is because the strings are different lengths. If the length of the pendulum strings were the same, it is predicted that they would all swing with the same pattern of motion.

• Friction is the force that resists motion.

• The force of friction between the sticks creates heat. When the flammable wood gets hot enough, a fire can start.

• One side of the ramp is rougher than the other. The rougher side of the ramp causes more friction, which slows things down.

• Although we want cars to be able to move quickly and smoothly down a road, we also want cars to be safe and not to slide off the road! Tire treads are carefully engineered to grip the road so the car can steer and turn safely. With tires, friction is a good thing.

• Fast motion could include the flapping of a bee's wings, a cheetah running, an airplane flying or a speaker vibrating. Some really slow motions could be a plant growing, a glacier sliding or a snail moving. No matter how slow motion is, it's still motion!