0 to 60: What's my Acceleration?

What kid (and adult for that matter), at some point in their life does not look at the speedometer? And as soon as they figure out that some cars go faster than others, life takes on a new dimension. Cars. 

So today's lesson starts in the car, or whatever your vehicle is.

Teacher Prep: Make sure you understand acceleration. Here is a good discussion of acceleration. You can also just read the textbook. Acceleration is the rate of change of velocity with time. Since velocity is a vector quantity- it has speed and direction- any time I change the speed or the direction I am accelerating. That is why I accelerate when I go around a curve even if I keep my speed the same. I have changed my direction. and since velocity is speed +direction, I have changed my velocity. And since acceleration is the rate of change of velocity, I am accelerating.

Materials Needed: car, stopwatch, acceleration worksheet, pens or pencils.

Activity:

Get all the kids in the car. Make sure they are buckled. Give one child a stop watch. If one child can safely see the speedometer from where they are sitting, make them the speed watcher. The next child gets to be the recorder. If you only have one child, he will be the timer and you will be the speed watcher. You will only record beginning and ending times and speeds.

Go to a place where there is not much traffic and the road is fairly straight. You will accelerate from 0 to whatever the speed limit is on the road. You can run this test several times, accelerating at different rates each time.

1. Come to a complete stop.  Make sure your timer and recorder are ready. Have your recorder write the beginning time and speed on the worksheet.

2. Have your timer say go and start timing.

3. Accelerate to whatever the speed limit is. (Please be safe.)

4. When you reach the speed limit, the speed watcher calls stop. Timer stops the stopwatch. 

5. Record the  final speed and final time.

6. Repeat several times.

7. Use the companion worksheet to figure out what your acceleration was.

Acceleration of gravity:

Galileo was the first to prove that the acceleration of a free falling object due to gravity was the same on heavy and light objects. The Galileo link under Resources on the Web has some great interactive media and a video showing the astronauts dropping a feather and a hammer on the moon.

Tree Climbing and Science. How cool can it get?

Here is an activity that calculates the height of an object by measuring the time of a free falling object. Great for all ages. My kids are tree climbers, so I let them climb a tree and drop 5 objects each from the spot they climbed to. I timed the drops and recorded them. Then we went inside and figured out how high they climbed. They loved it.

Resources on the Web:

Acceleration Worksheet

Why cars accelerate around a curve, even if their speed stays constant.

explanation of acceleration from Kuhn Academy. Good Resource.

explanation of acceleration around a curve from Kuhn Academy.

Lesson Plan on Galileo experiments, written materials and videos