Determining the Height     Making inclinometers and learning how to use them prepares you for making rockets  and measuring how high they fly.

 

Preparation and Materials   To measure the height of something tall, people will need to measure the distance from where they are standing to the object they are measuring.   So you’ll need another way to measure distance. You could use a measuring tape, or measure the distance with string, then measure the string with a meter stick.

 
 

Making Your Inclinometer          Here’s how to make a tool that you can use to measure how tall something is—or how high a rocket or kite flies.    Copies of Protractor for Inclinometer    Scissors    Clear tape    A 3" x 5" card    A hole punch    50 cm of string    A washer or other small weight with a hole in it    A sheet of 8 1/2 " x 11" paper (you can use paper from the recycling bin)      Print out a protractor. Cut very carefully on the straight line on one edge of the protractor.   Tape the protractor to the 3" x 5" card so that the straight side of the protractor matches up with the long side of the card.   Use the hole punch to punch a hole through the circle on the protractor.   Push one end of the string through the hole and through the washer. Tie the two ends of the string together making a loop on which the washer can slide freely.  Roll a sheet of paper into a cylinder that’s 8 1/2" long and about 1 inch across. Put tape on the seam so the paper stays rolled, then tape this cylinder to the card along the straight edge of the protractor. One end of the cylinder should line up with the edge of the card.

 
 

Using Your Inclinometer        After you make an inclinometer, you can use it to measure how high something is.   materials      An inclinometer       Something tall to measure       Pencil or pen       Paper       A tape measure or yard stick to measure distance in     centimeters      A copy of the Height Calculator Grid   Look through the end of the tube that sticks out from the card. You can look through the tube or sight along the top of the tube. It’s your choice.  Look at something that’s at eye level. Ask a friend to read the angle where the string crosses the protractor. If your inclinometer is level, the string should cross the protractor at about 0 degrees.   Look through the tube at the top of something tall. If you are indoors, look at something that’s near the ceiling. Ask your friend to read the angle where the string crosses the protractor.   When you look at something above your head, the inclinometer tilts. The string crossing the protractor marks the angle of the tilt of the inclinometer. Take a few steps toward the tall thing and check the angle on your inclinometer again. What happens to the angle on your inclinometer?  Rather than having your friend read the angle for you, look through the tube and pinch the string against the card to hold it in place. Then take the tube away from your eye and read the angle on the protractor. Have your friend watch you do this and tell you if you move the string and change the angle. Try this a few times, until you can do it without changing the angle.   Choose something tall to measure.   Look at the top of the object through your inclinometer and determine what angle your inclinometer measures. Write down this angle.  Measure how far it is (in centimeters) from where you are standing to the base of the object. Write down this distance.  Have a friend measure how far it is from the floor to your eye level. Write down this distance.  Follow the instructions on the Height Calculator Grid.

 
 

Height Calculator Grid    On the protractor at the corner of the Height Calculator grid, mark the angle you measured on your inclinometer. Draw a straight line that runs through the mark on the protractor, through the corner of the grid, and all the way across the paper.  Imagine that your eye is right by the protractor in the lower left-hand corner of the grid. The line at the bottom of the grid is a line parallel to the ground, at the level of your eyes. Each division on the grid represents 100 cm in the real world. Using this information and the distance you measured in Step 7 in Using Your Inclinometer, mark the object’s position on the bottom line of the grid.   Starting at the mark you just made, draw a straight line that’s perpendicular to the bottom line of the grid, starting at your mark.   Now you have a triangle. The height of this triangle tells you the distance from your eye-level line to the top of the object.   To get the height of the object, add the distance from the ground to your eye level (from Step 8 in Using Your Inclinometer) to the number you got above.

Print this Height Calculator Grid.

 

 

Before You Go to Your Launch Site  Here are a few preparations that will make it easier to keep track of what’s going on at the launch site.   Review how to use the inclinometer  If you need help remembering how to use it, see Height Site.

When you are using the inclinometers to follow a rocket’s flight, it’s important that you keep both eyes open. This makes it possible to track the rocket in flight. You can either sight through the tube with both eyes open or sight along the top of the tube. Either method will work. The important thing is to keep both eyes open.

 
 

Designate an Timer, and two Launchers

1st Launcher, pumps air into the bottle rocket.  2nd Launcher pulls the string to release the "U" ring holding the bottle in place.

The Timer will take two times beginning of launch to landing.  As soon as the rockets starts to fall, the timer needs to watch the time for the descent.

 

How the Launching Will Work

Here are the steps you will follow at the launch site:

 First, you will mark the launch site.
 Then you will mark part of a circle that’s 10 meters from the launch site. The person who is measuring the rocket’s height will stand on this arc. The timer will also stand on the 10 meter diameter. Once the timer has line of site on the rocket he/she needs to be able to give the record the data information.
 The Launcher will be standing next to the bottle rocket.  The recorder will be next to the launcher to make visual observations.  The recorder will also assist the launcher if needed.
 

Launching the Rocket

Here’s What to Take to the Launch Site
 

Clipboard	Launch data sheet	inclinometer
timer	pencils	stablizers
launch pad, string and "U" ring	bottle rocket	pump and tube

 
Getting ready  (optional to add water to your bottle)

First, mark the launch site. To accurately measure the rocket’s height, people need to view the rocket launching from a specific distance away. Have someone hold one end of your 10-meter string on the launch site while someone else stretches out the other end and marks an arc that is exactly 10 meters from the launch site. Everyone watching the launch will stand on the edge of this arc.
Second, in the center the 20 meter diameter, let up the launching pad.  Make sure the metal goes straight into the ground.  Thread the hose from underneath the launching pad and attached the rubber stopper to the opening of the bottle.  Slide the hose and bottle down into the launcher and hook the rim of the bottle, securing the "U"ring to the hole in the launching pad.
Connect the other end of the hose to the pump.  Pump no more than 20 times so you don't go over the limit of pressure inside the bottle. 
Then do a trial launch. Have everyone do a countdown, chanting together: "3, 2, 1, Launch!" On "Launch!" the Launcher will pull horizontally on the string to release the "U" ring that is holding the bottle down; the timer needs to start the stop watch(timer); the angler needs to have a visual on the bottle rocket to determine the angle.

Blast Off!

Start launching rockets, in the order that you previously established. Make sure you do three trials.
 
After you finish launching rockets, go back inside and complete the lab.  When you finish with your poster, have each person read over each section to make sure everything has been included.

Figuring Out How High Each Rocket Flew
 
 

Use the Rocket Height Calculator to figure out how high each rocket flew. The procedure here is very similar to the procedure you followed in Height Site.     The height of the triangle is how high the rocket flew above eye level. To get the height the rocket flew above the ground, people need to add on the distance from the ground to the eye. We've provided an average value for this number. People could get a more accurate measurement by measuring the eye level of all their measurers and figuring out the measurers’ average eye level. But that's more accurate than people probably need to get!Draw in all the trials, then draw in the average of the three trials.  You will need to create a key to identify which one is the average.  Why Use an Average Angle Measurement?  Some people may ask why they had to average three measurements. People often think of measuring as exact, but it isn't really. Every measurement is an estimate, a best guess at an answer. When you are using a new tool, like an inclinometer, you will come up with different estimates. Averaging these measurements improves the accuracy of your results.You also need to consider that your balloon will do "wierd" stuff.

Going Further—Building a Better Rocket
 
To move through the air, a rocket has to push air aside. Things that travel fast—like sports cars and jets—are shaped to minimize the amount of air they have to push aside to move forward. The fins on the back of a rocket help it slide through the air easily with its nose forward. People might want to experiment with adding more or fewer fins or using different-sized fins.
 
Imagine that they are pushing a kid on a wagon. With the same push, they can make a little kid in a wagon roll farther than a big kid. The rocket launcher gives your rocket a push with a puff of air. If two rockets have exactly the same design and weight distribution, a lighter rocket will fly farther with the same push than a heavier one. Can they make their rockets lighter?
 

So far, people have been launching rockets straight up to see how high they will fly. Now ask them to try launching rockets to see how great a distance they can get a rocket to fly. 
 

To get the greatest height, people held the launcher so it pointed straight up. To get the greatest distance, they’ll need to change the angle at which they hold the rocket launcher. What angle gives them the greatest distance? Encourage them to experiment to find out.

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