To introduce shapes I read aloud The Greedy Triangle (it's a must read for all grades) by Marilyn Burns. In a nutshell, this book is about a dissatisfied triangle that morphs into different shapes.
While reading the story aloud, I had my students predict which shape he would change into next (each time he changes, he adds one more side and angle) -- they made these predictions on their individual dry erase boards by drawing the shape and writing its name.
This book mentions several times how the triangle is 'dissatisfied' with his life, so I made sure to review the meaning of the prefix -dis when this word popped up.
After the story we practiced retelling it and created these visuals to help us remember all the important changes the triangle went through:
I then told students this would become part of their homework because they would need to retell the story to an adult. I stapled this sheet to the front of each visual so parents would know the expectation for the homework assignment.
This is what I have planned for tomorrow (they're going to love it).
We'll also become shape detectives and walk through the school looking for different examples of each shape. It should be another fun day.