Children love building and construction activities. Take this love for construction and turn it into a fun STEM activity by building bridges with straws.
Building Straw bridge is an educational activity for kids that naturally engages your kids to learn, understand, and enjoy science, engineering, technology, and mathematics.
Hands-on learning activities like making a straw bridge help children ideate, experiment, test their ideas and improve them besides positively influencing learning outcomes.
Straw Bridges is an exciting engineering project for kids that can keep your children learning and tinkering for hours. Help your kids take on the Straw Bridge challenge and channel their inner engineering skills!
Table Of Contents:
How to Make Beam Bridge Using Straws?
How to Make Truss Bridge With Straws?
But before we get started with How To Make a Straw Bridge, let’s dive in to learn the basics of bridges so we can understand the science behind these engineering marvels.
What is a Bridge?
A bridge is a structure that connects two points. It allows people, vehicles, and animals to cross over natural/man-made barriers such as rivers, valleys, or railways. Nowadays, we also get to see bridges above roads— they are built to reduce traffic!
Bridges are important because they make it easy for us to get from one side to the other without having to go around or swim across.
Types of Bridges
Learning about bridges can be an exciting experience for children— it encourages their creativity, problem-solving skills, and understanding of basic engineering principles.
Here are some common types of bridges:
1. Beam Bridge
Beam bridges or girder bridges are one of the earliest and easiest types of bridges.
The making of a beam bridge requires a horizontally-led beam (this is where vehicles drive by) and supporting pillars at all ends to take on the weight of the bridge. They are mostly used to cross small rivers, streams, or gaps.
For Examples: Manchac Swamp Bridge, Louisiana
Related: Check out Science Trivia for a mammoth collection of science quiz questions for elementary and high school.
2. Arch Bridge
Arch bridges are not only aesthetically pleasing but also are very economical. As the name suggests, arch bridges use reinforced arches to distribute and evenly support load.
They are supported on abutments found at both the ends of the curve. There are various types of arch bridges depending on the position of the deck relative to the arch.
- Deck Arch Bridge – In this arch bridge, the deck is completely above the arch. Example of Deck arch bridge: New River Gorge Bridge, West Virginia
- Through Arch Bridge – In through arch bridge, the arch has its base below the deck with the top of the arch rising above the deck. Sydney Harbour bridge is an example of this type of arch bridge.
The famous railway bridge taken by Hogwarts Express in Harry Potter movies is an arch bridge by the name Glenfinnan Viaduct. Can you guess which type of arch bridge it is?
3. Suspension Bridge
Suspension bridges are an iconic invention; they are suspended on (thick) steel cables that support the weight of the bridge.
These steel cables, called suspension cables, are interconnected and supported by tall towers, holding the bridge deck sturdily.
Famous suspension bridge examples include the Golden Gate Bridge and the Brooklyn Bridge.
4. Truss Bridge
Truss bridges are probably the strongest and safest bridge model. This type of bridge uses interconnected strong triangle frames, known as trusses, to support and balance the load on the deck!
Truss bridge example: Ikitsuki Bridge and Kingston-Rhinecliff Bridge
DIY Straw Bridge Building Activity for Students: Ideas for Straw Bridges Challenge
Now, let’s embark on the hands-on adventure of building straw bridges! In this creative and educational activity, children will learn to make straw bridges and test their own ideas of making bridges.
In this activity, we will be making two types of popular bridges:
- Beam Bridge
- Truss Bridge
While making a beam bridge with straws is pretty simple and is a great STEM activity for grade 4 students, truss straw bridges are slightly trickier and more time consuming. Thus, making it an apt stem projects for middle school.
Quick Tip: Make sure add a healthy dose of humour with these Science Jokes & Puns.
Beam Bridge: How to Make Straw Bridge Step by Step
Let us start with the simple beam bridge to warm up kids to do this straw bridge activity. Making a simple beam bridge is a great precursor activity to truss straw bridge project and will help children understand and appreciate the challenge of building straw bridges.
Supplies Needed For Straw Bridge:
- Drinking straws
- Tape (preferably masking tape)
- Lightweight objects for testing, such as coins or paper cups
Instructions to Make a Straw Bridge
Step 1: The first step in making this type of straw bridge is to make the pier to support the beam. To make the pier, take two straws and tape them near one end to make a V-shape.
Step 2: Next, add another straw to the pier to form a pyramid shape. Make two pyramid shaped straw piers.
Step 3: In the final step, take two straws and tape them on straw piers to form the deck of the straw bridge. You might need to adjust the straws to balance your beam bridge.
Once it is ready, place a paper cup on the deck of the bridge to test its strength. You can add coins in the cup to check how much weight it can bear.
Truss Bridge: How to Make a Bridge Out of Straws And Tape
Now, let us build a straw bridge to make a model of a truss bridge. It is one of the best straw bridge designs that uses triangle shapes made out of straw to give strength to the bridge design.
Materials needed for Straw Bridge
- Straws
- Tape
- Scissors
- Ruler
Step by Step Instructions For Straw Bridge Construction
Let’s bring our straw bridge to life with these steps: You can divide ‘straw bridge construction’ into three different steps:
- Making the base structure.
- Side supporting beams.
- Assembling everything together.
Step 1: Making of the base.
As straws are very light-weight, you need to have a strong base for your bridge! A strong base will provide stability to your bridge and will help your bridge avoid falling down unsteadily.
You can either make a base by joining vertical straws together or by sticking horizontal straws together. A horizontal straw bridge will be lighter!
On the other hand, a bridge base made of vertical straws will be sturdier because it will have more glue and volume.
- Horizontal bridge: Straws are usually 15-20 cm long. You can make them longer by fixing two sticks together. It’s easy because straws are bendable. Use tape to keep them connected. You will need 5-6 long straws for your horizontal base of the bridge. Stick them together horizontally and you have the base ready!
- Vertical bridge: Vertical bridge is more time-consuming but also the strongest straw bridge design. For this, you need two long straws (30-40 cm) and multiple small straws (all cut at 8cm precisely). Place the long straws parallel to each other, 8 cm apart. Now, start sticking the small straws vertically in between both the long straws until you cover the path between the long straws completely.
We choose to make a horizontal base.
Step 2: Making truss patterns
You need four triangle trusses!
- Cut 10 cm long straws for the triangle structure.
- You will need to stick three straws together to make one truss.
Step 3: Make the top of the truss bridge
To simplify the bridge design, tape 5-6 straws together, just like the base to make the top chord of the truss bridge.
Step 4: Assembling the parts of the bridge.
Attach the trusses to either side of the base of the bridge, so that the trusses stand on the base vertically. Lastly, tape the top chord of the bridge to the trusses to complete the bridge design.
That’s it! Your straw bridge is ready! Place lightweight objects on the bridge like toy car, small eraser, coin, increasing the weight to observe its strength and check at what weight the bridge collapses.
Take note of any areas that show signs of weakness and think of ways to improve the design and strength of the bridge. Adding more trusses to your design is one way to increase its strength.
Related: Pair this fun activity with more Exciting Engineering Activities for Kids.
Remember, this STEM bridge challenge is all about joy, learning, and discovering the magic of building bridges with your own hands. There is no one way to make straw bridges!
Let your creativity run wild as you experiment with different bridge designs and techniques, moulding your straw bridge into a masterpiece. Add more straws or tweak the arrangement to uncover the best straw bridge design that satisfies the engineer in you.
Final Thoughts…
Teaching your kids the basic knowledge behind construction and engineering is a healthy and an educational exercise. It allows them to expand and explore new horizons of human capabilities.
While creating this straw bridge, don’t forget to teach your kids about the different types of bridges and how/why they came to existence.
Teaching is fun when it’s backed by experiments and practical activities. At the same time, plan a short trip to nearby bridges in your town with your kids – they learn faster with examples!
