Part of Lesson Plan: Concrete Ratios

Activity Overview / Details

Upon completion of the power point presentation and notes on concrete ratios, the students need to retrieve their concrete batches and handouts.  One at a time, each students will bring their concrete batch to the front of the class.  Place the students concrete batch where it may be easily seen by all students in the class (front table or middle of shop floor) then have the student explain to the rest of the class the ratio of concrete ingredients he/she developed.  Have several weights (5 lb & 10 lb weights) or several masonry (red) bricks present.  Place the students concrete batch either in the middle of the table or on the shop floor and carefully place the weights or bricks on top of the batch. Start off with lighter weight and gradually applying more weight to the top of the batch.  The teacher and students will either calculate the weight or the number of bricks the batch can hold before crumbling.  Have the student record their weight (or number of bricks) on their handout.  After each student has had a chance to participate in the activity with their batches, the teacher will perform the activity with his/her batch with the correct concrete ratio (3-2-1, as expressed in the notes).  At the end of the class or activity, have the students clean-up the area. Have a discussion about the activity, (obvious observations with all the student ratios) again reviewing with the class the correct concrete ratio and the obvious effects ratios play in the strenght of concrete.  Note- this lesson and activity will lead into the next lesson on slump tests / water-to-cement ratios.