Water Bottle Rockets

At the end of the year, students get a chance to be the scientists in several projects. One of my absolute favorites is the water bottle rocket. The video shows the general design of the rockets and several launches. What I love about the project is that they chose one variable to change that will increase flight distance. Variables include fin shape, fin size, fin placement, volume of water, etc. I also love that there is not just one design that works. Here is the handout that I give to students.

Motion: A Change in Position

Motion is the change in position over time. Students often have a difficult time understanding that concept graphically, which is one of the big 8th grade science standards.  Vernier's Go!Motion sensor and software are excellent demonstration tools. The video demonstrates how both of them work together. Usually when I introduce it, I just give a volunteer student a big (1 x 1 yard) whiteboard and tell the student to walk towards and away from the sensor. The students can see the graph on the large video screen. They quickly pick up that the farther away from the sensor the student is, the higher on the graph the line is and vice versa. I have them draw graphs what what they think certain types of motion are and then we see if we can replicate the graph. The software also allows a prediction graph to be drawn and then students can see if they can walk that same motion graph. In later lessons, acceleration graphs are explored. Having a class set would be ideal, but having one sensor with a computer hooked up to a video projector will work just fine.

Pendulum

How does a pendulum work? Why can't the weight of the pendulum ever go as high as the starting height? Watch the video to find out.

Video Demo: Newton's 3rd Law

A simple demonstration of Newton's 3rd law of motion in action.  A rubber band under tension is cut, launching both the sled and the launching mechanism in equal and opposite directions.

Video Demo: Adding Forces

This is a fun and easy demo to teach what happens to objects when forces are acting in the same direction.  A series of balls are dropped together, one on top of another. The forces are added together, creating a larger force that propels the top ball to a much greater height.