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STRAW ROCKET - North Carolina Science Festival

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AFTERSCHOOL<br />

Big Idea<br />

Make a rocket!<br />

Time<br />

30–45 minutes<br />

You will need<br />

• empty plastic bottles<br />

• two different sizes of straws<br />

(wider and thinner)<br />

• clay or Play-Dough<br />

Recommended<br />

• tape<br />

• scissors<br />

• paper or index cards<br />

• ribbon<br />

Why We love it<br />

Flight is something that<br />

never gets old! This activity is<br />

something new that a lot of our<br />

students have not yet built and it<br />

gives them a chance to have fun<br />

experimenting and testing out<br />

their own ideas.<br />

Straw Rocket<br />

Set It Up<br />

Make sure that you have straws of two different widths<br />

that fit smoothly over each other. It’s a good idea to build<br />

your own rocket launcher ahead of time so younger kids<br />

can see a finished product. It also gives you a chance to<br />

understand the instructions and anticipate issues kids<br />

may face when building their own rockets. Depending<br />

on your space, you may want to create a testing zone<br />

or runway where students can safely launch their straw<br />

rockets. If you have tall ceilings or space outdoors, you<br />

could hang string or yarn, like a clothesline, for students<br />

to try to launch their straw rockets over.<br />

It’s showtime<br />

Let your group know that today’s challenge is to make a<br />

rocket that is launched using air power. Ask the group:<br />

What are some examples of objects that are powered<br />

by air The students may say things like windmills,<br />

sailboats, wind turbines, paper airplanes and gliders.<br />

Hold up an empty bottle and ask: what is inside the<br />

bottle The students might say nothing, or it’s empty.<br />

Guide them to think of air. The bottle may look empty,<br />

but it is full of air! Then ask: What would happen to the<br />

air inside if I were to squish the bottle Give the group a<br />

few minutes to share their ideas. When you squeeze the<br />

bottle some air will be pushed out of the bottle. Then ask<br />

the group: What if there was only a small opening for<br />

the air to leave the bottle Give the group a few minutes<br />

to share their ideas and predictions. Let the group know<br />

that the empty bottles will be the air powered engines<br />

for their rockets today.<br />

Guide the group through making their rockets,<br />

according to the instructions. It’s important that the<br />

rocket launcher is airtight. If kids are having a problem<br />

getting their rockets to launch, check the following:<br />

• Are there any holes or gaps in the seal between the<br />

clay and the bottle or the clay and the straw<br />

• Is the wide straw caught in the clay covering the<br />

bottle


It’s Showtime Cont’d<br />

Give the group time to experiment with and test their rockets. Have kids experiment<br />

to see how far and high they can get their rockets to go. Time permitting, allow<br />

students to make alterations to their rockets, like adding fins or wings to the outer<br />

straw. Encourage them to test their ideas and observe how those changes affect the<br />

rockets’ flight. Remind them to change one thing at a time in order to test different<br />

variables.<br />

As the designs progress you may need to ask open-ended questions or suggest<br />

different challenges to keep groups on task, like:<br />

• Can your straw rocket hit a target<br />

• How could you make your bottle launch the straw rocket farther Or higher<br />

• What could you do to make your straw rocket more accurate or fly more<br />

smoothly<br />

Be sure to give the group a 5 minute and 1 minute warning before you want them to<br />

stop experimenting. When the groups have finished experimenting and cleaned up,<br />

take a few minutes to discuss what they found to work well in their various designs<br />

and what did not work well. Ask them to explain their answers.<br />

Conclude this lesson by talking about the similarities and differences between the<br />

straw rockets and what they know about real rockets. Ask the group: Are the straw<br />

rockets that you designed anything like a real rocket What is similar or different<br />

Do you think real rockets work the same way as your straw rockets Give the group<br />

a few minutes to share their ideas. Rockets launched into space and the straw<br />

rockets the group experimented with today may not seem very similar, but they<br />

both encounter and need to overcome the same forces in order to work. A rocket<br />

that is launched into space doesn’t use air, but rather a very powerful combustible<br />

fuel, which is why you see fire coming from beneath it. That fuel, however, does the<br />

same thing that the blast of air does for the straw rocket – it creates a very important<br />

force needed for flight called thrust. Thrust is what pushes the rocket. In order for<br />

something to fly, like a rocket, there must be enough thrust to overcome its’ weight<br />

and the force of gravity pushing down on it.<br />

Why is This <strong>Science</strong><br />

This is aerospace engineering! Not only are we achieving something grand like flight<br />

but we are learning about forces and motion.<br />

When you squeeze the plastic bottle, the air inside the bottle is pushed into the<br />

straws. Since the top of the wide straw is plugged up, the air has no place to go, so the<br />

air pressure launches the straw into the air. For rockets that are launched into space<br />

or low-earth orbit, igniting massive amounts of fuel creates this pushing force. For<br />

both kinds of rockets, the pushing force has to be strong enough to overcome gravity<br />

in order to launch the rocket. Aiming the rockets is a challenge in real life just as it is<br />

for the straw rockets, and aerospace engineers use both mathematics and physics to<br />

help them aim, guide, and time the launches correctly.


The Morehead Twist<br />

• Try taping fins and/or nose cones cut from index cards to your straws. Do you<br />

notice any changes in how your rocket flies<br />

• Use ribbons to create streamers on your rocket.<br />

• Try using bigger bottles to see if you can get your straws to go farther.<br />

• Set up an air “obstacle course” to see if students can get their straws to land in or<br />

go through hula hoops.<br />

• Use masking tape to create targets on the floor or walls.<br />

• Think bigger! Use paper towel rolls and tubing to make stomp rockets!<br />

Differentiation<br />

Grades K – 1<br />

It can be difficult for this age group to make the connection between the clay and<br />

the soda bottle airtight, so help may be necessary. Having the clay at the end of<br />

the straw can sometimes be too heavy — we like to have tape as an alternative.<br />

Grades 2 – 3<br />

We like to show them how to build the bottle, but let<br />

them figure out how to make the rocket.<br />

Grades 4 – 5<br />

Depending on your group, we like to tell them what they are trying to build,<br />

give them the supplies and let them go for it without too much direction.<br />

Additional Information<br />

This pairs well with our Thorp <strong>Science</strong> Night activities “Paper Flying Machines” and<br />

“Stomp Rockets”.<br />

Sources & Links<br />

Dragonfly TV<br />

The Exploratorium<br />

Howtosmile.org<br />

proudly produced by<br />

AFTERSCHOOL<br />

© 2013, The University of <strong>North</strong> <strong>Carolina</strong> at Chapel Hill. All rights reserved.<br />

Permission is granted to duplicate for educational purposes only.


AFTERSCHOOL<br />

Supplies<br />

• empty plastic bottles<br />

• two different sizes of straws<br />

(wider and thinner)<br />

• clay or Play-Dough<br />

Recommended<br />

• tape<br />

• scissors<br />

• paper or index cards<br />

• ribbon<br />

Straw Rocket<br />

Instructions<br />

What to Do<br />

1. Build a rocket launcher:<br />

• Hold a thin straw about an inch down into the<br />

mouth of the bottle.<br />

• Wrap a ball of clay about the size of a quarter<br />

around the bottle opening, sealing it tightly<br />

around the straw and the bottle so no air can<br />

escape.<br />

• Now squeeze the bottle. Do you feel air coming<br />

out of the top of the straw<br />

2. Build a rocket. Seal up one end of a wide straw with a<br />

small ball of clay. Place the open end of the the straw<br />

over the thinner straw in the rocket launcher.<br />

3. Blast off! Aim the straws AWAY from any hazards<br />

or people. Wrap both hands around the bottle and<br />

squeeze, collapsing the bottle quickly. Your rocket<br />

should fly through the air. If the rocket doesn’t<br />

launch, practice squeezing the bottle harder and<br />

check that there are no holes in the clay.<br />

4. Design more rockets. Make different rockets by<br />

attaching wings and tails to other wide straws. Use<br />

construction paper, string or bits of streamers. Test<br />

the rockets. Which ones flew the farthest Did any<br />

curve in the air How did your additions change the<br />

way they flew<br />

Safety tip!<br />

Always point your rocket AWAY from people before<br />

launching it!<br />

© 2013, The University of <strong>North</strong> <strong>Carolina</strong> at Chapel Hill. All rights reserved.<br />

Permission is granted to duplicate for educational purposes only.

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