In this project, students must build a contraption that can protect an egg from being crushed. The only materials they are allowed to work with are flat wooden toothpicks and wood glue. The force being applied to the egg contraption is in the form of a 5 gallon bucket falling from above. If you're a teacher friend, continue reading below. If not... don't bother with the reasons for the experiment and skip to the fun part.
You can check out the videos on step 4 for a better idea of what happens to the final product!
Objectives: Student will demonstrate ability to...
1. plan and build a device to protect an egg from forces acting on it.
2. identify the forces acting on their egg contraption and build accordingly.
3. compare and contrast what worked vs. what didn't work.
4. reflect upon what they would do differently.
5. collaborate in small groups throughout the process.
6. calculate the forces acting on their egg (momentum, force, acceleration, speed, velocity)
7. identify where Newton's 3 laws of motion can be observed in the schematic of the experiment.
This lesson can be easily differentiated. (less toothpicks, less time to build, increased mass in the bucket, higher drop height... you get it)
Students can work in pairs or go at it alone. I do not recommend bigger groupings.
Step 1: Materials
For the build you will need...
a. 200 flat wooden toothpicks. (I found the mass of 200 toothpicks is 11.3 grams. I measured out 11.5 because some toothpicks are bound to be bent / broken / too skinny... You can have the kids count them out after you hand them out if they think you shorted them. This way you don't have to take time to exchange bad toothpicks)
b. Wood glue
c. Wax paper
d. Graph paper
e. 3.5 oz bathroom cups (I like plastic better because they hold up for multiple uses)
plastic Easter egg, ruler, scissors
For the test you will need...
a. 5 gallon bucket (1)
b. Eggs (One for each project built)
c. A pulley (optional... just helps decrease friction)
d. Rope (length depends on how high your ceiling is)
e. mass to add to the bucket (I used textbooks)
f. a meter stick or yard stick to measure how high the bucket is when you drop it.
Step 2: The Pre-build
1. Imagine where the force is coming from. Where will you need the most support? Hint: A roof will NOT help protect your egg.
2. This is a three dimensional project. (You need to plan out the walls, build the walls laying flat on the table, let the walls dry, and then stand the walls up and glue them together. Make sure you check out the picture that shows what NOT to do.)
3. Don't waste your time and wait for toothpicks to dry. There is always something you can work on.
I start class with a warm up (do now) on one of Newton's Laws and how it relates to the project. After reviewing student generated responses, they can get their project and start / continue building. They will need a refill on glue at the start of class each day.
Step 3: The Build
Work on top of the wax paper.
Glue toothpicks together.
Let toothpicks dry.
Protect egg at all costs!
Below are some ideas my students came up with.