For week two (2), you will be creating a balloon boat using a sponge, straw, balloon, and other materials. Materials that have air in them or tiny holes (like a sponge) can float on top of the water easier than materials that don’t have air (like a brick). This concept is called buoyancy. If you have ever worn pool floaties or a life jacket you have experienced how air can help things float. The balloon boat is moved through the water by the force of the air coming out of the balloon and straw. As the air moves out of the straw, it pushes the boat in the opposite direction. Friction is the force that resists motion between two objects or surfaces. When you first put your boat in the water, friction prevents the balloon boat from moving very much. After blowing up the balloon through the straw, and releasing it, the air in the balloon travels through the straw and out the open end. This pushes the boat forward, overcoming the friction of the water that is pushing back against it. The boat moves forward because the force of the released air pushing the boat is greater than the force of the friction that is resisting its movement.
Essential Concepts:
Area of Focus: Physics, Engineering
Aim: To create a boat that is powered by air
- Friction: is a type of force that resists motion between two objects or surfaces.
- Buoyancy: is a type of force exerted on an object that is wholly or partly immersed in a fluid. When something floats we call it buoyant.
- Density: is a measurement that compares the amount of matter an object has to its volume. Density describes how compact or concentrated something is.
Area of Focus: Physics, Engineering
Aim: To create a boat that is powered by air
Procedure/Instructions:
Make sure to perform the activity as a team (parent/grandparent/adult/helper and student). Please read the instructions out loud and make sure you have all the equipment before you start.
Make sure to perform the activity as a team (parent/grandparent/adult/helper and student). Please read the instructions out loud and make sure you have all the equipment before you start.
- Student: Using a ruler, find the middle of the short edge of the sponge and make a small mark. Then, draw a diagonal line from the middle mark to the longer edge of the sponge and repeat on the other side. It should look like “<” or “>” or on the sponge.
- Parent: Using a knife or scissors, cut along the lines, removing two triangle shaped sections from the sponge.
- Student: Bend the straw, then cut the longer end of the straw in half.
- Parent or Student: Stretch out the balloon by blowing it up and then let the air out. This will make it easier to blow up the balloon later.
- Insert the one end of the straw into the balloon (1-2 inches) and secure the straw and balloon together with a rubber band or pipe cleaner. ***Make sure the balloon is secured tightly to the straw, but not so tight that you crush the straw and prevent air from flowing through the straw.
- Student: Push the straw (attached to the balloon) through the top of the sponge through the hole.
- Student: Blow up your balloon through the straw. Once you have blown up your balloon, cover the end of the straw with your thumb or finger until your boat is in the water to stop the air escaping from the balloon. Position the straw towards the non-pointy end of your sponge.
- Now let go and watch your boat go!
Connection to the real world:
Elkhart County is home to the pontoon boat company, Barletta Boats! The concepts of friction and buoyancy that you explored in this activity are very important in this industry and applying these concepts are essential to building better and faster boats. Knowing what materials are more buoyant allows engineers to design boats of all shapes and sizes that will not sink. Marine engineers design boats with air compartments to allow them to stay afloat, even when they are carrying very heavy things. Boat motors have propellers that move air and water very quickly, pushing the boat in the opposite direction of the air and water movement.
Tuesday @10am - Live from the Lab
The Lab in a Bag team will walk through how to make a balloon boat and discuss why some things sink and others float and why that's important when making a boat. |
Wednesday @10am - Out & About
We visit behind the scenes at Barletta Boats and chat with CEO Bill Fenech! We also visit Amy & Braelyn at Wellfield Botanic Gardens who will give some tips on how to keep your plants alive and healthy! |
Thursday @4:30 pm - Q&A
The Lab in a Bag team will do additional demonstrations and answer your questions about how to keep your boat from going around in circles, potential modifications you can do to make it go faster and talk more about buoyancy and forces! |
Challenges:
- What could you use instead of a sponge? Can you find other materials in your home that are buoyant?
- How could you modify your boat to go faster? What would happen if you tried to use two straws? Two balloons? Less weight?
- Try blowing up the balloon to different sizes and see how that impacts the speed it moves through the water.
- What could you do to the sponge to make it more buoyant?
Don't forget to post a response to Flipgrid page for your chance to enter our weekly prize draw!
Guest password: ETHOS2021 |