STEAM Crabs

Factoid A record breaking Red King crab weighed 24 pounds and was 20-30 years old. The age of a crab is difficult to determine and can only be estimated by studying molting and growth patterns.

Directions You are to research the ages and sizes of three different types of crabs. Create a chart for all three. Next, write the rule for each category and write an expression that relates the size of the crab to its age.

Years 1 ½ 2 2 ½ 3 3 ½ Width 4 in. 4 ½ in. 5 in. 5 ½ in. 6 in. EXAMPLE: The Dungeness crab is 4 inches wide in 1 ½ years. He reaches about 5.75 inches at age 3 or 4. My chart shows how he might grow. Years 1 ½ 2 2 ½ 3 3 ½ Width 4 in. 4 ½ in. 5 in. 5 ½ in. 6 in. The Rule for Years: Start with 1 ½. Add ½ The Rule for Width: Start with 4. Add ½ Expression for Dungeness Crab: Y + 2 ½ = W

S looking up crab growth and width of shell T using technology to look up different types of crabs E engineering a growth chart A creating an artistic poster M completing a chart on the patterns of growth and creating an algebraic expression as well as rules for each category.