Caterpillar to Chrysalis: Elapsed Time

(1) Introduction (10 minutes):

Begin by showing captivating images or videos of butterflies emerging from chrysalises (see resources section). Briefly discuss the stages of the butterfly life cycle.
Introduce the essential question and explain that math can help us understand the timing of these transformations.

(2) Direct Instruction (25 minutes):

• Problem 1 (Elapsed Time): A Monarch caterpillar entered its chrysalis at 9:15 am. It emerged as a butterfly at 9:50 am. How long was the caterpillar in the chrysalis?

Direct Instruction: "We need to find the elapsed time. We can count by 5-minute intervals: 9:15, 9:20, 9:25...9:50. Or, we can subtract the start time from the end time. 50 minutes - 15 minutes is 35 minutes. So, the caterpillar was in the chrysalis for 35 minutes."
 

• Problem 2 (End Time): A Black Swallowtail caterpillar entered its chrysalis at 2:30 pm. It was in the chrysalis for 45 minutes. What time did it emerge as a butterfly?

Direct Instruction: "We know the start time and the elapsed time. We need to find the end time. We add the elapsed time to the start time. 30 minutes + 45 minutes is 75 minutes. Since there are 60 minutes in an hour, 75 minutes is 1 hour and 15 minutes. So, we add 1 hour and 15 minutes to 2:30 pm. The butterfly emerged at 3:45 pm."
 

• Problem 3 (Start Time): A Gulf Fritillary butterfly emerged from its chrysalis at 11:25 am. It was in the chrysalis for 20 minutes. What time did it enter the chrysalis?

Direct Instruction: "We know the end time and the elapsed time. We need to find the start time. We subtract the elapsed time from the end time. 25 minutes - 20 minutes is 5 minutes. So, we subtract 20 minutes from 11:25 am. The caterpillar entered the chrysalis at 11:05 am."

(3) Independent Practice (20 minutes):

Distribute the "Caterpillar Time" worksheet (see resources section).
Encourage students to use the strategies discussed during direct instruction to solve the problems.

(4) Wrap-up (5 minutes):

Review the essential question and discuss how addition and subtraction of time intervals are used to solve real-world problems.
Have students share their strategies for solving the worksheet problems.

Differentiation: Provide clocks or number lines to help them visualize the time intervals. Work one-on-one or in small groups to review the concepts of elapsed time, start time, and end time. Use smaller time intervals in the problems.

Extension: Include problems with multiple steps (e.g., a caterpillar enters its chrysalis, stays for a certain time, then another caterpillar enters, how much time passes between the first caterpillar entering and the second emerging?). Use larger time intervals or problems that involve crossing over the hour (e.g., starting at 1:50 pm and adding 25 minutes). Ask them to create their own word problems about caterpillar transformations and time.

Use the performance task linked in the resources tab to assess student learning outcomes.