Summary Hang a weight on elastic bands and measure how far they stretch, to compare their stretchiness. Students can experiment with linking together bands. Science content Chemistry: States of Matter, Properties of Materials (K-7) Physics: Motion and Forces, Newton’s Laws, Gravity (K, 2, 6) Science competencies (+ questioning + manipulation + others that are in every activity) Questioning/predicting: predicting (1 up), hypothesizing (7) Planning/conducting: measuring (non-standard K up, standard 2 up) Planning/conducting: data collection/recording (K up) Planning/conducting: planning investigations (3 up) Planning/conducting: fair testing and controlling variables (5 up) Processing/analyzing: classifying data, finding patterns (1 up) Processing/analyzing: comparing observations with predictions (1 up) Processing/analyzing: considering alternative explanations (5 up) Lessons activity is in Properties of materials: sticky, stretchy, foaming, floating Materials masking tape hooks e.g. picture rail hooks elastic band selection tubs for elastic bands baggie or pouch containing two rolls of coins, or other weight, with hook attached worksheet with ruler on it measuring tape (for long stretches) Procedure Before the class, tape hooks to the edges of desks. Discuss stretchiness as a property of a materials, and tell students they will compare how stretchy different elastic bands are. Demonstrate how to hang an elastic band from a hook, then hang the weight on the band. Measure the length of the stretched elastic band, making sure the zero of the ruler/measuring tape is at the top of the band, while reading off the number at the bottom of the band. Students measure the stretchiness of different bands. Then they can try doubling up the bands and looping them together to measure their combined stretchiness. At the molecular level, stretchy materials have molecules that are curled up and coiled. When the materials is stretched, they uncoil and straighten out, but when released return to their coiled form. Attached documents stretch_worksheet_half_page.pdf Grades taught Gr 1 Gr 2 Gr 3
