Introduction: Marble Cannon
Building a cannon for physics isn't really what I thought I'd be doing this year, but here's how I did it.
Step 1: Step 1: Get Supplies
I went to Home Depot to find all my supplies, but the workers didn't even know the way around so, maybe go to Lowe's instead. You will need:
- A 2 by 4 (I got one of the ones that was precut at 4 feet)
- A 1 by 4 (again I got one that was precut at 4 feet)
- A 3/4 inch PVC pipe (precut at 2 feet)
- A 3/4 inch wooden dowel (precut at 2 feet)
- A 1/4 inch wooden dowel (precut at 2 feet)
- Two tension springs (the ones I found were meant for doors)
- A 2-inch door Hinge
- A wooden baseboard
- 45-degree wooden block (I made mine)
- Zip ties
- Hot glue gun (and glue)
- Screws (most of my things came with screws, but not everything does)
- A Sharpie
- A drill
- A hacksaw
- A saw
- Protractor
Step 2: Step 2: Cut Things Down to Size
Unless you want to make a massive oversized cannon you're gonna need to cut some things down to size. Cut the things down to the lengths listed.
- 3/4 inch wooden dowel - 57cm
- 1/4 inch wooden dowel - 8.25cm
- PVC pipe - 45cm
- Wooden board - 50cm by 30cm
- 2 by 4 - 50cm (length)
- 1 by 4 - 50cm (length)
- With the excess of the 2 by 4
- cut a square 8.25cm by 8.25cm
- then cut from one corner to the other
- this creates a 45-degree block
Step 3: Step 3: Assembling Your Cannon
- Heat up your glue
- Add glue up the center of your 1 by 4
- Attach the PVC pipe to it
- Use zip ties around the board and PVC to secure it
- Note that the PVC won't stay stuck to the board like this, but it will create a grove where the PVC pipe will rest when you go top shoot later
- Once that's dry and cooled, take off any zip ties that are lower than the bottom half
- Cut off any excess length on the zip ties that are hanging off all floppy
- Set this aside for now
Step 4: Step 4: Building the Base
- Take your wooden board and 2 by 4 and attach them to each other with 4 screws
- Place one screw in each corner to get it securely attached
- If you want additional support you could attach a screw in either side in the middle of the board
- Set this aside
Step 5: Step 5: Putting It All Together
- Screw your door hinge onto the back of your cannon
- do this so that you can open it to raise up and down when attached to the base
- Screw the other part of the door hinge onto the end of the 2 by 4
- With the protractor measure where different angles lay on the 2 by 4
- Do this while holding the 45-degree block under it as what would be holding it up
- Mark a line and label the degree measure at the front end of the wooden block
- I recommend every five degrees
- In the center of the top if the 45-degree block (the hypotenuse of the triangle) drill a hole through, about a quarter of an inch diameter so your small dowel can fit inside
- Taking the 45-degree block place it on the 2 by 4 with the front at one of your degree lines
- Mark a dot or line where the hole is on the board
- I just put a pencil inside of the hole and marked it that way
- Repeat this for all of your degree measures
- Drill the same size hole that's in your wooden block for all of your marks
- Label all of the holes with the appropriate degree measure
- I did these ones in sharpie so they were easily visible, whereas the other ones were done in pencil
- Write your name on your masterpiece and you're done
Step 6: Step 6: Do the Math
Using your data from firing find the time and initial velocity
To find time use the equation pictured above (yellow)
To find initial velocity use kinematic equations (orange)
I wanted to fill the table, so I also found the final velocity (red)
My work for my trials is pictured above