A few notes: Give students time to decide on a plan before letting them begin the challenge. Talk about having a plan B. Sometimes I select the groups, other times I let students pick their partners. I think they need to experience both ways.
Challenge 1: Paper Chain (groups of 1-3 students)
I prefer to let my students work in groups of two for this challenge. Each group needs one sheet of construction paper, scissors and a glue stick. You determine the amount of time. The longest chain wins the challenge!
More information from the Math Chick: The Great Chain Race
Challenge 2: Spaghetti Tower (groups of 3 students)
Students need a handful of marshmallows and spaghetti noodles. I do not count these out! This challenge was more difficult than my students expected.
More information from All About 3rd Grade: Spaghetti Tower
Challenge 3: Coffee Filter Chromatography (groups of 4-5 students)
Important tip: Make sure you try a black Mr. Sketch Scented Marker. This marker had very different results than Crayola and Expo. (see picture)
Students simply make a line with a black marker near the bottom of a coffee filter. Put the filter in a cup of water. (about 1/2 inch)
More information: Coffee Filter Chromatography
These activities are great any time of the year, but the end of year is when I usually let students do the most challenges. My students made sure they included details about STEM in their letters to future second graders. It made me realize how much they enjoyed these activities.
Short video about being an engineer: NASA for Kids: Intro to Engineering