Simple & Powered Machines Set

Stamping Letters

Apply knowledge and skills related to levers, cams, gears, observing and improving, and fair testing.

45-90 min.
Grades 6-8

The Problem

(3-5 Minutes)

It is too windy to play outside so Jill is helping out in the post office stamping letters. Her arm is getting sore from stamping, she is very tired and she wishes there was a way of using the wind to help her!

Can you think of a way to help her out?


Design Brief

(3-5 Minutes)

Design and make a wind-powered stamping machine:
• it must make a mark on thin paper
• the more times it stamps the mark within one minute, the better
• it must be powered by the wind from a desk fan placed approximately one meter (≈ one yard) away

  1. Make a sketch of the idea you designed and made.
  2. Label the three most important parts, explaining how they work.
  3. Suggest three improvements.

Suggested Model Solution

(20-25 minutes)

Note: You are advised not to share this image with students.


Fair testing and Fun

(15-20 Minutes)

Does the stamper mechanism work in the wind?
Start the fan one meter away from the stamper and see if the mechanism moves. You don’t need to actually test with paper yet.

Does it actually stamp paper?
Cut up several pieces of paper to be the letters. Stamp half of them with the machine. Give all the pieces to someone else. Can he or she tell you which ones are stamped and which ones are not?

How productive is it?
Have a stamping race. With the stamper one meter (≈ one yard) from the fan, how many letters can your model stamp in one minute? The more the better.

How energy efficient is it?
How far can you move the stamper away from the wind and still stamp letters? The further away it works, the more energy efficient it is.

How safe is it?
Check to see if you can get your finger stamped by mistake. The safest stamper will be easy to use but hard to hurt yourself on.

Need Help

Look at:

The Hammer




Extra Challenges

(25-30 Minutes)

Make a special conveyor system to carry letters under the stamper.

Make a real ink transfer stamp out of an old eraser with a ballpoint ink message on it.
Can you write in mirror writing so you can read the message? How many times will it stamp before you need to re-ink it?

Design and make a system that will tell you automatically how many times the stamper has stamped.

Teacher Support

Students will be able to apply the knowledge and skills of:
Renewable energy
Observing, improving, and measuring
Applying principles of fair testing and product safety

Crosscutting Concepts

Science and Engineering Practices
Asking questions and Defining Problems
Developing and using models
Planning and carrying out investigations
Analyzing and interpreting data
Using mathematics, Informational and Computer
Technology, and computational thinking
Constructing explanations and designing solutions
Engaging in argument from evidence
Obtaining, evaluating, and communicating information

Common Core Mathematics Standards
7.RP.A / 6.NS.B / 6.EE.C / 7.EE.B / 8.EE.B / 8.F.B / 6.SP.A

Common Core English Language Arts
SL 6.1 / 6.2 / 7.1 / 7.4 / 8.1
RST 6-8.3 / 6-8.4 / 6-8.7
WHST 6-8.1 / 6-8.7 / 6-8.8 / 6-8.9

Student Material

Student Worksheet

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