Summary Build seed models that are adapted for dispersion by wind. Attach tissue paper, feathers and other light materials to a foam ball, then test how far they can travel in a wind from a fan. Science content Biology: Features, Adaptations of Living Things (K, 1, 3, 7) Biology: Life Cycles (2) Earth/Space: Weather, Seasons, Climate Change (K, 1, 4, 7) 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: comparing observations with predictions (1 up) Processing/analyzing: considering alternative explanations (5 up) Evaluating: inferring (3 up) Lessons activity is in Seeds Materials foam balls light materials with a large surface area e.g. tissue paper, tin foil, feathers, cotton balls masking tape fan metre rule of measuring tape, to measure how far the seed designs go optional: worksheet to record results Procedure Best run after looking at real wind-blown seeds, with wings and parachutes. Discuss how seeds are light and wide, to catch the wind and are blown further away from the parent plant. Show students the foam ball, and tell them that this is a seed. The other materials can be used to make the wings, parachute or other structures around the seed. Stick the materials into the foam with tiny pieces of tape, or use the pipe cleaners to secure them. The goal is to make a seed that stays in the air as long as possible (so make them light and wide). To test how long a seed stays in the air: hold your seed above your head. Blow out as you drop the seed, to mimic the wind. Compare your seed with its structures to a plain foam ball, to see if your seed moves further. Make sure to do three or more trials, to fairly compare how the plain seed and your seed with structures. Even better, place a blowing fan in an area with space, which students can drop the seeds in front of. Drop the plain foam ball 'seed' and the seed model with added structures side by side, just above the blowing air of the fan. As they hit the fan wind, see which one moves further or stays in the air longer. Discussion: Best design is (1) light so the force of gravity does not pull it down too fast, so it has time to go sideways; (2) wide so that it catches the wind and gets pushed sideways as it stays in the air longer. Real seeds are not 'designed' like this, but the different shapes arose by chance. Some shapes gave a seed a greater chance of survival, and so its characteristics were passed to the next generation (through the DNA). This is called natural selection. If one feature leads to greater survival, that seed-style is able to make more plants. The feature (or adaptation) is selected for. Video on the recently understood aerodynamics of a dandelion seed and why they stay aloft for so long: https://www.youtube.com/watch?v=N2UbaDV9O9Q This activity inspired by:http://www.earthrangers.org/wp-content/uploads/2016/05/NeedForSeed.pdfhttps://www.scientificamerican.com/article/gone-with-the-wind-plant-see…http://www.accessexcellence.org/AE/AEC/AEF/1995/taylor_seeds.html Notes Outside wind sounds a nice idea to do this lesson in, but is too variable to really compare the plain ball and seeds they make. Maybe take their models outside to play with in the wind at the end of the activity. Add a sticky seed model idea: hold up a piece of fur. Give students pipe cleaner pieces to push into their balls, then throw at the fur to stick to it. OR they can use their hair. The ones with hooks hold better?? Grades taught Gr 1 Gr 2 Gr 4 Gr 5
