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**Quick** I forgot I didn't explain my project very well, here is my experimental design:

**Defining Question**: By how much will a ball's speed change when its size, weight, and how hot it is outside changes?

**Hypotheses:** The size of the ball will be the greatest factor in deciding the average acceleration of air resistance. The second important factor is the density of the ball. Finally, the least affecting factor will be the temperature of the air.

**Independent Variables:**

The Density of the ball: 5-10 levels per ball size, control will be unaltered density (I won't fill the control with weight)

**The Outside Temperature:** 4-6 levels, control to be decided

**The Size of the Ball:** 4-5 levels, Control will be the middle sized balls.

**Dependent Variable:**

The average acceleration of air resistance

**Number of Trials:**

4 trials per density

**Constants:**

The Starting Velocity of the ball.

The Angle the ball is released.

The Ground Level

The Starting Location

**Procedure:**

1. Set up the trebuchet in a level area

2. Place the first ball in the trebuchet

3. Launch, makeing sure to measure the starting velocity of the ball

4. Time how long it takes for the ball to hit the ground

5. Measure the distance between the landing point and the point of release

6. Discover the average acceleration for that time (using equation a=2(d/t)-2v, where d is the change in distance in meters, v is the starting velocity in meters per second, t is the time in seconds, and a is the average acceleration of the ball)

7. Repeat until you have 4 tests of that ball

8. Use different density balls while repeating steps 3-7 until all densities have been used.

9. Change the ball size and repeat 2-8

10. Repeat step 9 until all ball sizes have been used

11. Repeat steps 1-10 when the temperature changes

12. Repeat step 11 until sufficient data is collected