“Seeing” forces

This lesson was developed in a Lesson Study Project over three years. The authors are Karen Vanderheyden, Markeeta Clayton, Nikki Grimes and John Graybill. They called this lesson–

“Send in the Reinforcements” You can download it here.

The lesson is the first in a series of explorations of the way members and joints distribute load in a bridge. The original idea came from a video on the Annenberg Foundation learner.org, which I highly recommend. We have been unable to locate the video clip of the original activity, although hopefully it is still there.

The beauty of this activity is that it allows students to “see” force vectors, at least their direction. Magnitude is represented by the thickness of the paper which transmits the force.

Jet Straw Lesson on Newton’s Third Law

Jet Straw

Victoria Deneroff, PhD

I stole this idea many years ago from the NASA website, although I have adapted it to be an engineering challenge rather than a science activity. The original appears to no longer be easily available on the web.

Design Challenge

Build a jet straw air engine which produces the highest rotational speed.

What is a Jet Straw?

The jet straw is a simple engine that is powered by air released from a balloon. It is a system consisting of a balloon, bendable straw, rubber band, straight pin and pencil eraser. The straight pin is used as a pivot point around which the system rotates.

Beginning Ideas

In your journal write down what you think is the best way to construct a jet straw engine.

Stage 1: Messing Around and Asking Questions

Use the rubber band to attach the balloon to the straw so that it will rotate around a pivot point. Use your journal to record the different ways you tried to make the engine, and what you finally tried that worked. Brainstorm questions that will help you make a jet straw which rotates more quickly. Make a list of the questions, and in pairs decide on one to investigate.

Stage 2: Tests and Experiments

Decide how you are going to find the answer to your question by conducting an experiment. Each person should write down the step-by-step directions for conducting the experiment. The procedure must provide a way for you to collect quantitative data by taking measurements. What these measurements might be is up to your team. Consult with the teacher when you think you have a good procedure.

Stage 3: Observations and Measurements

Record your observations and measurements in your journal. As a class we will discuss your observations and what they mean.

Stage 4: Claims

What do you claim is the best way to design a jet straw engine, based on your tests? Write in your journal

Stage 5: Evidence

In your journal, explain how you know this is the best way.

Stage 6: Prepare a poster which explains

A. What your question is.

B. What your findings are.

C. The scientific explanation for your findings

D. What your recommendations are for others who want to build a jet straw engine.

E. We will discuss all the findings as a class.

Stage 7: Reflection

Reread your original questions. How have your original ideas changed, or grown? What do you wonder about now?

Stage 8: Redesign.

With your partner, revise your jet straw engine design, making a sketch of it in your journal. Build your revised design and record how it works.