Buzz
Building a balloon-powered car is a fun craft project and an educational scientific experiment that you can do with children. This activity teaches kids that wind energy can propel an object and introduces them to other physics principles like momentum, force, friction, and speed. It’s also a fantastic lesson on recycling and reusing discarded items to create cool toys. You only need a few simple materials: a car base, a straw, wooden skewers, tape, and a balloon.
Steps
Making a balloon-powered car is simple
Cut a piece of cardboard into a 7.5 x 15 cm rectangle. Use a pencil and ruler to draw the rectangle first, then cut it with scissors or a craft knife.
- You can also use a foam core. This is the type of material often used for presentation boards.
- If you want to decorate your car, you can paint the cardboard with acrylic paint or apply colored tape to the surface. Let the paint dry before proceeding.
Cut two 7.5 cm long sections of straw. Only use the straight, smooth part of the straw, avoiding the twisted section. These two straw pieces will be used to secure the wheels and axle in place.
Attach the two straw sections to the cardboard piece using tape. Position the straws horizontally at each end of the cardboard, keeping each straw about 1.3 cm from the edge. Make sure the straws are straight and parallel to the edges of the cardboard. If the straws are bent, your car will not run in a straight line. Secure the straws onto the cardboard using tape.
- Use strong tape, like fabric tape, to prevent the straws from wobbling.
- Ensure that the tape runs the full length of the straw.
Cut two wooden skewers into 10 cm long pieces. First, remove the pointed ends, then cut two 10 cm sections. You will need two pieces like this. These will serve as the axles for the wheels.
- If your scissors aren’t strong enough to cut the skewers, you can try using wire cutters.
- If you can’t find wooden skewers, you can use lollipop sticks instead. Make sure they spin freely inside the straw sections.
Insert the two wooden skewer sections into the straws. Each end of the skewer should stick out about 1.3 cm. The wheels will be attached to the skewers. This allows the axles to rotate freely inside the straws, enabling the car to move.
Create the wheels. Use a bottle cap or a large coin to trace four circles onto the cardboard. Cut out the circles using scissors or a craft knife, trying to keep them as even as possible.
- You can also use bottle caps instead of the cardboard circles.
Attach the wheels to the skewers. Make a hole in the center of each wheel. Slide the wheels onto the ends of the skewers. Ensure the wheels don’t touch the cardboard base to avoid them getting stuck. If the wheels feel loose, you can apply a drop of glue or place some clay at the ends of the skewers. Don’t worry, this won’t prevent the wheels from turning.
- If you’re using cardboard or foam core for the wheels, you can use a pencil or skewer to make the holes.
- If you’re using bottle caps, you’ll need a nail and hammer to punch the holes. Ask an adult for help.
Insert a straw into the balloon and secure it in place. Slide a straw into the balloon about 5 cm. Wrap tape around the balloon’s opening and the straw to seal it. Make sure it’s airtight. You need to tape it securely.
- Use a regular balloon, not a water balloon, long balloon, heart-shaped balloon, alien-shaped balloon, worm-shaped balloon, etc.
Attach the straw and balloon setup to the car base. Place the car on its wheels. Align the straw and balloon along the car base, making sure it’s straight. The balloon should be resting on the cardboard, and the straw should extend out at one end. Secure the straw to the cardboard with tape.
- If the straw extends past the edge of the car base, that’s fine, but you may need to trim it if it touches the ground.
- Ensure the balloon doesn’t extend beyond the car base; otherwise, the balloon will touch the ground and block the car’s movement.
Let the car go. Blow air into the balloon through the straw. Pinch the end of the straw to prevent air from escaping. Place the car on a smooth, flat surface. Let go of the straw and watch the car move!
- The straw should be at the back of the car, and the balloon should be at the front.
- If the balloon doesn’t inflate, there may be a leak. Try wrapping more tape around the balloon’s opening.
- If the balloon still doesn’t inflate, it might have a hole in it. You’ll need to use a new balloon.
Make a car using a juice box
Find a small juice box. You can also use a small milk carton. To make the car look even better, you can paint the box with acrylic paint or cover it with colored tape or paper, etc.
- Ensure the box is clean and dry.
Cut two straws to the width of the juice box. The juice box will have a front, back, and two sides. Cut the straws to the same length as the width of the front and back of the box.
- Be sure to use the straight part of the straw, not the twisted end.
Attach the straw pieces to the ends of the juice box. Place the box with the front facing you. Lay the straw pieces on top of the box, positioning them about 1.3 cm from both the front and back edges. Use tape to secure the straws to the box. These straws will hold the axles and wheels in place.
- Make sure the straws are straight. If they’re bent, your car won’t roll straight.
- Use strong adhesive tape, like fabric tape, to ensure a secure hold.
Cut two skewers to make the axles. First, remove the pointed ends, then cut the skewers into two pieces, each about 2.5 cm longer than the width of the juice box.
- If you don’t have skewers, you can use lollipop sticks instead. Just make sure they can fit easily into the straws.
Insert the skewers into the straws. The skewers should extend about 1.3 cm from both ends of the straws. These ends will hold the wheels.
Attach the wheels. Fill a bottle cap with clay or foam and press it onto the ends of the skewers. Make sure the clay doesn’t touch the straw. You can also use hot glue to secure it.
- If you don't have bottle caps, you can use buttons as substitutes. Alternatively, you can cut cardboard into circles to create wheels. Just make sure they are all the same size.
Attach the balloon to one end of a straw. Insert the straw into the balloon about 5 cm. Wrap tape around the opening of the balloon, securing it to the straw. Ensure there are no gaps.
Stick the straw to the juice box. Position the balloon-attached straw in the center of the box. Part of the balloon should hang off the back of the car, while the other end of the straw should extend from the front. Make sure the straw is aligned straight and then secure it in place with tape.
- Use strong adhesive tape, such as fabric tape, to keep it secure.
- If the straw is too long, trim it down. You only need about 2.5 cm extending beyond the edge of the box.
Let the car go. Blow air into the straw to inflate the balloon. Pinch the end of the straw to prevent air from escaping. Place the car on a smooth, flat surface. Let go of the straw and watch your car zoom away!
- Inflate the balloon fully.
- Don’t tie the straw closed; just pinch the end tightly.
- Once ready, release the balloon and enjoy watching your car race!
Make a car using a plastic bottle
Clean the plastic bottle. You can use either a water bottle or a soda bottle. Remove the cap and peel off the label. Wash the bottle thoroughly and let it dry.
- A small water bottle is the ideal size for this project.
- Make sure the bottle is completely clean, especially if it originally contained soda or fruit juice.
Cut two straws to match the width of the water bottle. Measure the width at the bottom of the bottle and cut two straw pieces to this length. Be sure to use the straight parts of the straws, avoiding any twisted sections. These straw pieces will serve as the axles for the wheels.
Attach the straw pieces to the sides of the water bottle. Tape the first straw about 2.5 cm from the bottom of the bottle. Attach the second straw a similar distance below the neck of the bottle. Ensure that both straws are straight and parallel to each other. If they are angled, your car won't move in a straight line.
- If your bottle has grooves, use them as a guide to align the straws correctly.
- Use strong, durable tape such as fabric tape to secure the straws.
Cut two wooden skewers to make axles. Trim the pointed ends and then cut the skewers to a length about 2.5 cm longer than the width of the bottle. The skewers need to be long enough to pass through the straws and hold the wheels.
Insert the skewers into the straws. The ends of the skewers should extend about 1.3 cm beyond both ends of the straws. Then, you'll attach the wheels to these ends.
Create the wheels. Find four bottle caps. Draw an X on each cap to mark the center of the circle. Use a hammer and a nail to create a hole at the center of the X.
- You can also draw four circles on cardboard and cut them out to make wheels.
- If you prefer, you can replace the bottle caps with buttons. Just be sure to use buttons of the same size and avoid making holes in them.
- If you're not comfortable using a hammer and nails, you can place a small piece of foam into each bottle cap.
Attach the wheels. Place the wheels onto the ends of the wooden skewers. Make sure the inside of the bottle cap faces outward. Don’t press the wheels too tightly against the bottle to avoid jamming. If they feel too loose, you can secure them with a drop of glue or use some clay to hold them in place.
- If you're using buttons, simply glue them to each end of the skewer with hot glue.
- If you're using foam pieces in the bottle caps, just insert the skewers into them.
Cut an X shape into the bottom of the bottle, just below the upper arc. Place the "car" on the four wheels. Find a spot at the bottom of the bottle just under the curve and use a craft knife to cut two intersecting diagonal lines in an X shape. This is where you'll attach the "engine" of the car.
Attach the balloon to the end of a straw using tape. Insert a straw about 30 cm long into the balloon. Wrap tape tightly around the neck of the balloon. Ensure that the tape goes over the balloon's opening and sticks to the straw. Make sure there's no gap.
- When inserting the straw into the balloon, make sure the twisted end goes in first.
Insert the straw into the bottle. Insert the end of the straw into the X-shaped cut you made at the bottom of the bottle. Then push the straw through the neck of the bottle until about 2.5 cm of the straw protrudes from the mouth of the bottle. If the straw is too long, trim it.
- The straw will naturally bend at the twisted part inside the bottle.
Cho xe chạy. Thổi không khí vào bóng bay qua ống hút. Bóp đầu ống hút sao cho không khí không xì ra ngoài. Đặt ô tô lên mặt phẳng nhẵn và buông tay khỏi ống hút. Ngắm ô tô chạy tới và tới nữa!
- Thổi căng quả bóng qua đầu ống hút ở cuối chai.
- Dùng ngón tay bịt đầu ống hút sau khi thổi căng quả bóng.
- Khi đã sẵn sàng, bạn hãy bỏ tay khỏi ống hút và ngắm ô tô chạy.
Lời khuyên
- Nếu đây là một dự án của lớp, bạn hãy cho bọn trẻ thi xem ô tô của ai chạy xa nhất hay nhanh nhất. Đây là một cách rất hay để thực hiện phương pháp khoa học và phát triển nhiều giả thuyết khác nhau về cách cải tiến chiếc ô tô.
- Tốt nhất là sử dụng bóng bay tròn thay vì bóng bay dài và hẹp. Bóng bay tròn sẽ nén không khí và tạo thêm lực cho chiếc ô tô.
- Những chiếc hộp nhẹ như hộp các-tông đựng giày sẽ giúp ô tô của bạn chạy nhanh hơn.
- Bánh xe to sẽ đi được khoảng cách xa hơn.
- Bạn có thể gắn một chiếc ống hút vào đuôi xe. Nó sẽ đóng vai trò như chiếc bánh lái và giúp cho xe chạy thẳng.
- Làm cho chiếc xe mang tính khí động học (trơn và thẳng để băng đi nhanh hơn) bằng cách thử nghiệm với nhiều vật liệu và bánh xe khác nhau cũng như các đặc điểm thiết kế khác.
- Dùng bóng bay to hơn để tạo nhiều lực hơn và giúp ô tô chạy nhanh hơn. Khi bạn buông tay, thậm chí nó có thể bay!
- Bạn cũng có thể dùng các đĩa CD cũ để làm bánh xe.
- Bánh xe có thể làm bằng các nắp chai.
- Đừng gắn bong bóng ngược đầu, vì như vậy ô tô sẽ chạy giật lùi.
Cảnh báo
- Cẩn thận với những chiếc đinh ghim nhọn. Bạn nên bẻ thành góc thích hợp hoặc dùng kìm bẻ cong thành vòng để cho chúng khỏi trượt ra khỏi trục ống hút.
- Đừng thổi quá nhiều; bạn có thể bị choáng váng đấy.
- Nếu bị dị ứng với cao su thiên nhiên, bạn hãy dùng loại bóng bay không có cao su thiên nhiên.
- Trẻ em cần được giám sát khi sử dụng kéo và đinh ghim sắc nhọn.
Items you'll need
How to make a simple balloon-powered car
- Cardboard
- Scissors
- Wooden skewers
- Straw
- Balloon
- Tape
How to make a car from a juice box
- Juice box
- Scissors
- Wooden skewers
- Straw
- Tape
- 4 bottle caps
- Clay, hot glue, etc...
How to make a car from a water bottle
- Water bottle
- Scissors
- Wooden skewers
- Straw
- Bottle caps, buttons, cardboard, etc...
- Balloon
- Tape
