Before Pythagoras (the equation, that is) even comes into the discussion, we should be asking our students to describe projectile motions that they see in their everyday lives. Focus on the big picture question: What are the different factors that determine the range of a projectile? Projectile motion problems can easily become algebra problems that focus on identifying the right number in a diagram and substituting it into the correct equation. We want them to see projectile motion in baseball games, long football throws (think the famous Hail Mary, game-winning touchdown pass by Dallas Cowboys quarterback Roger Staubach to Drew Pearson in a 1975 NFL playoff game), the human cannonball at the circus, rockets, and shooting hoops.

And then there is Angry Birds. The game actually helps your instruction by outlining the bird’s path with dots that are placed at the same time interval, as well as leaving these trajectory paths visible for the next turn. This allows for an overlap and visual comparison of bird trajectories that have different initial angles and velocities. I stress, the goal here is not to try and knock down the structures and take out the pigs, but to use the game platform as a demonstration tool that will get their attention, and to see the flying birds as your projectiles. In a later blog we will look at the structures for teaching force and motion.

Using Angry Birds, you can highlight many of the main points about projectile motion. Things like:

- How do you get a bird to travel the farthest? Answer, 45-degree initial launch angle.
- Can you find multiple launch angles that will land on the same spot? Answer, there are two per spot, and they are complementary angles.
- What happens when you launch birds at the same angle but change the initial velocity?
- What happens when you launch birds at the same velocity but change the initial angle?
- What launch angles have the longest time in flight? The shortest?

The best levels to use for teaching projectile motion meet these criteria: good open field and no high structures to get in the way of the flight, use of the basic red birds, and having many birds to play with. Theme 1, levels 2 and 3 (see video at the beginning of this blog) offer many birds and a fairly open field for long-range projectiles. Videos of all levels can be found here.

**Extra Credit:**

In a Wired Science blog, Rhett Allain demonstrates how you can use a simple video tracker program to map the trajectory of the birds in these videos to actually calculate the size of the birds (with the assumption that gravity in the Angry Bird world is also 9.8 m/s^2). You will be surprised at the result—these red birds are BIG!

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