- Category: Project Activities
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- Written by Bryan
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Marshmallow shooters or guns are a great little project for you and your children. Marshmallow guns require very little money, skill and effort to make. They are the best fun toy guns you can make yourself for just a couple bucks. Since they work a lot like Legos®, they are constant fun when they can remake and add-on to these toys. They are great for all ages and safe. This article includes a PDF of the schematic to build your own marshmallow gun. This article also includes an excellent section on how science can be taught through this project.
Marshmallow Shooter Materials
I originally purchased these materials a few years ago from a home improvement center. I have listed the cost that I paid for the pieces below.
Total Cost for 1 toy gun = $2.00 (approximately)
ALL PIECES BELOW ARE 1/2 inch PVC Length of tubing (drinking water grade)
- 1/2 inch PVC 10 feet length$1.62
- T joint 10 pack$2.56
- L joint 10 pack$1.92
- end cap individual piece$0.23
- coupler 10 pack (optional)$1.28
Building a Marshmallow Shooter Skill Level and Time Required
Skill Level = Easy
Total time = 15 minutes
You can choose to cut the tubing with a hacksaw which is the common method. We decided to go with an old-fashioned pipe cutter. This made it possible for the younger kids to do the entire project without serious risk of injury. Please see the tip below about pipe cutter and fitting tube into pieces.
At the time my 7 & 8 year old sons had no problems measuring and cutting the toy gun pieces. They also found it very easy to take the pieces they had and assemble them in the right order using the hand-drawn diagram that I copied from instructables.com.
- Always supervise children when working with dangerous tools!
- Use a small pipe cutter instead of hacksaw if you are working with younger kids.
- A pipe cutter will cause ends of pipe to expand slightly but they will still fit into connectors; they will just be tighter.
- Do not glue pieces together. This will allow you to take the toy gun apart if it jams or you want to add more sections to it. As mentioned, these toy gun pieces work a lot like Legos®.
- Let your kids be creative and modify the design and test different configurations. The whole Lego® aspect is cool!
- Make a little science study out of this project. Study physics principles as they relate to the marshmallow shooter such as velocity, trajectories and the venturi effect.
- Fill in the extra cavities of the toy gun that are not part of the natural passageway of the projectile marshmallow. This allows the air pressure when you blow to be more directed in the ammo’s firing pathway. See diagram for more details.
- Filling up the front handle with marshmallows for a semi-automatic weapon might sound like a good idea but the marshmallows tend to get stuck.
- Fill up a sandwich baggie with mini-marshmallows and duct tape bag to the gun barrel for faster and easier loading.
- Marshmallows will stick to the carpet and floor in your house so keep the battles outside. This will keep mom happy. Also, look out for attracting unwanted ants to these sweet treats on the ground.
Ways to Play with Marshmallow Shooters
We have used these at birthday parties and scouting events. They are always a crowd favorite with the kids (and dads too!). There are several games and activities that can be done around marshmallow shooters. We have listed a few here to help generate ideas.
- Pre-cut pieces of pipe and add the necessary joints into a large zip-top bag for each kid attending a party. These can then either be built as one of the activities or sent home with the kids as a party favor, just include a copy of the instructions for the assembly.
- Set up a battle. Divide into two teams and create bases with a flag then have the teams try to capture each other's flag. Each kid can get hit three times by a marshmallow before they are removed. Some arguments will develop over whether someone was hit or not but this is typical of any game like this.
- Have a target practice session. Set up five Styrofoam cups on a fence or some other high surface. Have everyone take turns with 10 marshmallows to see how many cups they can knock over.
- Who can shoot the farthest contest. See who can shoot the farthest by having everyone line up and take turns firing into a field. Take a look at the science section below and especially the part about trajectories. See who can find the optimal angle to shoot where the greatest distance is achieved.
Here are some scientific principles that can be taught in connection with building and playing with Marshmallow Shooters. Some of these scientific principles may not have a direct correlation to how the marshmallow shooter works, but there is enough of a connection to make it interesting for kids making them. In actuality, my college physics professors would probably deny that I was ever their student if they saw this. But that shouldn't stop us from creating teachable moments and sparking interest in science and mathematics for children.
Scientific principle: Velocity in its simplest definition is how fast an object moves in a given direction. It is a Vector measurement, which means that it has both a magnitude and a direction. Vectors are usually one of the first things students learn in Physics Class and is worth a mention to young scientists. Most objects do not maintain a steady velocity, which means they are slowing down or speeding up. This is known as Acceleration, which is a more advanced topic using Velocity. Because of this change, measurements are done as an average over a specific distance or for a given time period. The formula to calculate the rate (r) of velocity is the change in distance (d) divided by the change in time (t). It is typically displayed as m/s or meters per second. In class you would write it out like this where the triangle means change: r = Δd / Δt . Watch a video here that explains this.
How it applies: Most of the scientific principles listed here have to do with the movement of air through the PVC pipes and the movement of the marshmallow through the pipes and through the air. How fast your breath moves through the pvc pipe and how fast the marshmallow moves through the air is important for all of the rest of the scientific principles listed below. It can be a little difficult to measure but it should be fun to at least try. Have someone stand next to the person with a marshmallow shooter with a stop watch. At the same time the marshmallow is launched, start the stopwatch then stop it once the marshmallow hits the ground or some other object. Measure the distance to the stopping point in meters and divide that by the numbers of seconds it took to get there. This is the Velocity of the marshmallow. Have fun measuring each person's shot and see who gets the highest rate of velocity.
Scientific principle: Trajectory is the path an object takes as it travels for a specific time over a distance. The specific form that relates to this article is called the Ballistic Trajectory of a Projectile. This is usually noticed by observing projectiles or objects that are shot or thrown. There are some basic formulas for calculating distance traveled, time of flight and angle of reach. These formulas involve variables such as the gravity constant, initial launch velocity, angle of launch, height at launch, horizontal distance, and time of flight. With a certain number of the variables, a person can calculate other pieces of the puzzle. These formulas are listed on Wikipedia. Here is a video here that helps us understand how this works. Also, check out this simple diagram.
How it applies: It is much more fun to play with marshmallow shooters when they can deliver their ammo at the greatest distance and with the most accuracy. In order to do this we must understand the most optimal path for a marshmallow to follow to its target. This is an arc that starts from the shooter reaches an apex then descends toward the target. There is actually an optimal angle to launch which produces the greatest distance. Too low and the marshmallow will skid to the ground too soon and too high and gravity will take it down before it could go its greatest distance. A great experiment would be to try to come up with the optimal angle considering the force your breath can produce at launch, the wind and gravity.
Scientific principle: The Venturi Effect can be explained in many complicated ways; however, for kids it may be best to simply define it as when a flow of air or water is forced to go through a more constricted area it is forced to speed up. This depends on pressure and volume not changing. This can be easily shown a couple of ways. One way is to have them stand next to a door in a large room like a gym and see if they feel the air rushing through the door or in the same way if a lot of people are exiting the gym, the people at the door will need to move faster through the door or everyone gets backed up.
How it applies: This physics principle is a bit of stretch to apply to marshmallow shooter, but can still be interesting and fun for kids to think about. We take a lot of breath in our mouth and force it through a constricted space of the ¼ inch pvc tube. The air will obviously accelerate more than what we just blow because of this. If you really want to try this further make part of the marshmallow shooter out of ½ inch pvc pipe and use a coupling connector piece that tapers from ½ inch to ¼ inch on the straight part of the shooter where the marshmallow exits. This will decrease the final area where the marshmallow will travel on its way out of the tube, which should make the projectile gain velocity.
Scientific principle: This is specific type of projectile for which the marshmallow is classified. In weapons terms this means that the projectile does not carry an explosive charge. Relating back through history this would be similar to rocks thrown with catapults or even arrows launched with bows. The science is simple: the projectile object has energy and when it comes in contact with another object it transfers that energy to the new object. Factors such as mass of both objects, velocity of both objects, and angle of impact all determine how much energy is transferred. Remember from earlier that velocity includes direction so both objects can be moving in directions that will change the way energy is transferred.
How it applies: There are different ways to apply this. Depending on your family's view of guns, you can select baseball as an alternative analogy to projectiles fired from weapons. The point is that a marshmallow does not hurt someone or damage other objects because it is extremely light and travels very slowly because we use our breath. The more mass an object has and the higher the velocity, the more energy will be transferred.