Engineering Design ProcessThink about the steps of the Engineering Design Process (EDP).

1.Why do we have to define the problem before we begin our design?

2.Why is research important?

Polymer Balls

Engineering Design Challenge:Create a bouncing ball

Your Challenge• Develop a polymer bouncy ball by determining

the correct ratio of materials given. • Ball needs to have maximum bounce. In other

words, create a ball that bounces the highest. • Ball should be more environmentally-friendly than current balls made. • Determine the optimal ratio of materials to

produce a prototype ball using no more than 40mL of materials given.

PROTOTYPE “Guidelines”

CRITERIA

• Consists of a high percentage of eco-friendly materials

• Bounces a minimum of 9 cm

CONSTRAINTS

• Uses no more than 40mL of materials given

• Has a diameter less than 4 cm

Engineering Design Process

Ionic Vs. Covalent

• Ionic Bonds–Form crystals–High melting and boiling points–Hard and brittle–Metal to Nonmetal–Solutions conduct electricity

Ionic Vs. Covalent

• Covalent Bonds–Some form crystalline pattern –Low melting and boiling points–Soft and flexible–Nonmetal to nonmetal–Solutions do not conduct electricity

Which ball do you want to produce?– http://tinyurl.com/ab62hsh

What are polymers?

• Commonly referred to as “plastic”

• Chemical compounds bonded together in long, repeating chains

• Can be man made or natural

• May have elastic properties• Most are made up of

covalent bonds

Polymer Composite

Minerals• Cornstarch– Thickens when subjected to shearing forces or shock– Natural mineral extracted from corn

• Borax– Used in adhesive manufacturing– Natural mineral – Used as a multi-purpose cleaner – Toxic! Do not consume or inhale!

• White Glue– Slow drying adhesive – Can be made from skim milk, baking soda, vinegar

Determining Ratios

Decide as a team the ratios of chemicals that you should use to create a bouncing ball that will reach optimal height.

Example: You use 30 mL of Borax, 20 mL of cornstarch, and 10 mL of glue to make your bouncing ball.– What is the ratio of Borax to the total amount?– What is the continued ratio of Borax to

cornstarch to glue? 30:20:10

30:60

PROTOTYPE “Guidelines”

CRITERIA

• Consists of a high percentage of eco-friendly materials

• Bounces a minimum of 9 cm

CONSTRAINTS

• Uses no more than 40mL of materials given

• Has a diameter less than 4 cm

Engineering Design Process

Think about the prototype design your team created on Day 1.•Did your ball meet your expectations? Why or why not?•What are some changes you would make to your design if you could redesign and create another model?