Catapults: A Launch Through Time!

Have you ever wondered how people in ancient times launched big rocks at castles? They used amazing machines called catapults! Catapults are some of the oldest and most powerful inventions in history, and they teach us a lot about how things move.

What is a Catapult?

Simply put, a catapult is a machine designed to launch a projectile (an object thrown into the air) over a long distance without the use of explosive devices. Imagine a giant arm that you pull back, load up, and then release to send something flying!

A Blast from the Past: Catapult History

Catapults have been around for thousands of years. The ancient Greeks and Romans used them in battles to break down city walls and defend their positions. During the Middle Ages, catapults like the trebuchet became even more powerful and could hurl huge stones hundreds of feet! They were the ultimate war machines of their time.

Even today, while we don't use them for war in the same way, the ideas behind catapults are still used in many things we see, like how a baseball pitching machine works, or even how some toys launch small objects.

The Science of the Launch: How They Work

Catapults might look complicated, but they use some simple, yet powerful, science principles:

1. The Lever: A Simple Machine

The most important part of many catapults is the lever. A lever is one of the six simple machines. It's basically a stiff bar that pivots, or turns, around a fixed point called a fulcrum.

Think about a seesaw:

• When you push down on one side (the effort), the other side goes up.
• The point in the middle where it balances is the fulcrum.

In a catapult, the arm that launches the object acts like a lever. You apply force to one end (often by pulling it back or twisting a rope), and the other end moves rapidly, flinging your projectile.

2. Energy in Motion: Potential and Kinetic

Catapults are all about energy!

• Potential Energy: This is stored energy. When you pull back the arm of a catapult, you are storing potential energy in it. It's like stretching a rubber band – the energy is there, waiting to be released.
• Kinetic Energy: This is the energy of motion. When you let go of the catapult arm, all that stored potential energy turns into kinetic energy. The arm moves, and the object flies through the air because of this kinetic energy.

So, you store energy by pulling the arm back (potential), and then you release it to make the object move (kinetic)! The harder you pull it back, the more potential energy you store, and the further your object will fly!

Ready to Build?

Now that you know a little about what catapults are and how they work, you're ready to start thinking about how to build your own. Keep these ideas of levers and energy in mind as you design your Catapult Building Guide! It's time to become an engineer!

Catapult Design Worksheet

Name: ____________________________

Part 1: Imagine & Plan (Before Building)

Before you start building, let's think about your catapult design!

1. What is the goal of your catapult? (e.g., launch a marshmallow far, launch it high, hit a target?)
   
   
   
   

2. Materials Check: You can only use popsicle sticks, hot glue, and one plastic spoon or bottle cap for the basket. How will these materials limit or inspire your design?
   
   
   
   

3. Sketch Your Design: In the space below, draw your initial idea for your catapult. Label the main parts: the base, the arm, and the fulcrum (the pivot point). Think about how you will make it strong and stable.

   (Draw your catapult design here)
   
   
   
   
   
   
   
   
   
   
   
   
   

4. Why did you choose this design? What do you think will make it effective?
   
   
   
   

Part 2: Build & Improve (During & After Building)

Now it's time to build! Remember, it's okay if your first design doesn't work perfectly. Engineers always test and improve!

1. Challenges During Building: What was the hardest part about building your catapult? How did you solve it?
   
   
   
   

2. Testing Your Catapult: Describe how you tested your catapult. What did you launch? Where did it go?
   
   
   
   

3. Improvements: Based on your testing, what changes did you make or would you make to your catapult to make it better? (e.g., make the base stronger, change the fulcrum, shorten/lengthen the arm?)
   
   
   
   

4. What was the most successful part of your catapult?
   
   
   
   

5. What did you learn about levers or energy while building and testing your catapult?
   
   
   
   

Catapult Building Guide: Popsicle Power!

Welcome, engineers! This guide will help you build your very own catapult using popsicle sticks and hot glue. Remember, there are many ways to build a catapult, so this is just one idea to get you started. Feel free to be creative and make it your own!

Materials You Will Need:

• Popsicle sticks (lots of them!)
• Hot glue gun and glue sticks (use with teacher supervision!)
• 1 plastic spoon or bottle cap (for the launching basket)
• Small projectile (like a marshmallow or pom-pom)

Step 1: Building a Strong Base (15-20 minutes)

The base of your catapult needs to be strong and stable so it doesn't tip over when you launch. Think of it like the foundation of a building!

• Make a square/rectangle: Lay out 4-6 popsicle sticks side-by-side. Glue two more sticks across the ends to hold them together, forming a sturdy rectangle.
• Build up layers: Repeat the first step to make another identical rectangle. Glue these two rectangles on top of each other to create a thicker, stronger base.
• Add support beams: For extra strength, glue a few more sticks diagonally or perpendicularly across your base.

Why is a strong base important?

Step 2: Creating the Launching Arm (10-15 minutes)

This is the part that will actually hold and launch your projectile!

• Stack and glue: Take two popsicle sticks and glue them together flat. This will be the main part of your arm.
• Attach the basket: Glue your plastic spoon or bottle cap to one end of the stacked sticks. Make sure it's secure enough to hold your projectile.

How does the length of your arm affect the launch?

Step 3: Adding the Fulcrum (The Pivot Point) (10-15 minutes)

The fulcrum is what your launching arm will pivot on. It's super important for how your catapult works!

• Choose your spot: Decide where your fulcrum will be on your base. It could be in the middle, or closer to one end. Where you place it will change how your catapult launches.
• Build a small support: You can create a fulcrum by gluing two or three popsicle sticks on their sides, standing up, on your base. They should be just wide enough apart for your launching arm to fit in between and pivot freely.
• Test the pivot: Place your launching arm between the fulcrum supports. Does it rock back and forth easily? If not, adjust your supports.

What does a fulcrum do?

Step 4: Connecting the Arm to the Base (10-15 minutes)

Now to bring it all together!

• Secure the arm: You can use a single popsicle stick glued across the top of your fulcrum supports to keep the launching arm in place, but still allow it to pivot up and down. Make sure it's not too tight.
• Add a stopper: Glue a popsicle stick vertically (standing up) towards the back of your base, behind your fulcrum. This stick will act as a stopper for your launching arm, giving it something to push against when you pull it back.

Why do you need a stopper for the arm?

Step 5: Reinforce and Refine (10 minutes)

Look over your catapult. Are there any wobbly parts? Does it feel strong?

• Add more glue: Reinforce any joints or connections that look weak with more hot glue.
• Test carefully: Gently pull back the arm and let it snap forward. Does it move smoothly? If not, see what might be getting stuck.

Step 6: Launch Time! (The Best Part!) (10 minutes)

• Place a small marshmallow or pom-pom in your spoon/basket.
• Pull the arm back against the stopper.
• RELEASE! See how far your projectile flies!

Don't forget to record your observations and improvements on your Catapult Design Worksheet! Good luck, and have fun launching!

Catapult Project Rubric: Popsicle Power!

Student Name: ____________________________

This rubric will be used to assess your catapult project based on your design, construction, functionality, and your reflection on the process. Read it carefully to understand the expectations.

Total Score: ________ / 24

Teacher Comments:

Catapult Launch Analysis Lab

Name: ____________________________

Welcome to your Catapult Launch Analysis Lab! In this activity, you will collect data from your catapult launches and then use a simplified kinematic equation to analyze the vertical motion of your marshmallow. Remember, engineers often use models to understand complex systems!

Part 1: Data Collection

Work with your team to launch your catapult multiple times. For each launch, carefully measure the following:

1. Initial Launch Height (h): Measure the height (in feet) from the ground to where the marshmallow rests in your catapult's spoon just before you launch it.
   
   
   

2. Total Flight Time (t): Use a stopwatch to measure the total time (in seconds) the marshmallow is in the air, from launch to landing. Do several trials and record the average.
   
   
   

3. Horizontal Distance (d): Measure the horizontal distance (in feet) your marshmallow travels from the launch point to where it lands.
   
   
   

Record your data in the table below:

Part 2: Simplified Vertical Motion Analysis

For this lab, we will use a simplified model to understand how time and vertical position are related. The equation we will use is:

y = 16t^2 + h

Where:

• y is a target vertical position (in feet) we are interested in.
• t is the time (in seconds).
• h is the initial launch height (in feet) from your data.

While real projectile motion involves more complex physics, this model helps us practice using the quadratic formula.

Problem: Reaching a Target Height

Imagine your marshmallow needs to reach a target height y_target that is 5 feet higher than your average initial launch height (h). Using the simplified equation y_target = 16t^2 + h, calculate the time t it would take to reach this target height. You will need to use the quadratic formula: t = [-b ± sqrt(b^2 - 4ac)] / 2a.

1. What is your average Initial Launch Height (h) from your data?
   h = ____________ ft
   
   
   

2. Calculate your Target Height (y_target):
   y_target = h + 5 ft = ____________ ft
   
   
   

3. Rearrange the equation y_target = 16t^2 + h into the standard quadratic form at^2 + bt + c = 0:
   (Hint: Move all terms to one side, setting the equation equal to zero. Remember that y_target and h are values you now have.)
   
   
   
   
   
   
   
   
   
   
   

4. Identify the values for a, b, and c for your quadratic equation:
   a = ____________
   
   
   
   b = ____________
   
   
   
   c = ____________
   
   
   

5. Use the quadratic formula to solve for t. Show your work below. (Remember, time cannot be negative! If you get two positive solutions, consider which one makes more sense in the context of reaching a higher point.)
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

   Calculated Time (t): ____________ seconds
   
   
   

Part 3: Reflection

1. How close was your calculated time t (from Part 2) to your actual measured Total Flight Time (from Part 1)? What might account for any differences?
   
   
   

2. What limitations do you think this simplified vertical motion model (y = 16t^2 + h) has compared to how a real marshmallow flies through the air?