In our physics class, our project was to make a kinetic art sculpture. We chose to make a sand pendulum because we thought it looked cool, and it utilized pendulums, a physics concept. We were skeptical if it was going to work, and we were very surprised and excited by the results.
This project is pretty easy to make, while it might seem pretty difficult.
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Step 1: Materials and Tools
- Sand (we used colored sand so it would stand out)
- 4-5 Wooden Dowels (depending on length of dowels)
- Water bottle(s)
- Ruler or Yard Stick
- Duct Tape
- Funnel (optional)
Step 2: Making the Bottles
To hang the bottles upside down, we first cut a small hole in the bottom of the water bottle, just big enough to put the string through.
Then, we pulled the string through the bottom to the top of the bottle, and tied a good knot in the string that was big enough to cover the hole so that sand would not fall through. We then pulled the string back into the bottle, and cut the string two feet long. (picture 1).
Next, we punctured the cap in the bottle, which is where the sand will flow through. We then measured to see if the hole was big enough by putting a small amount of sand in the bottle, and seeing if it flowed continuously. Once we got the right size hole, we put tape over the hole so no sand would fall out when we added it. (picture 2).
Lastly, we filled the bottle with sand about half way up. (picture 3). We used a funnel to make it easier to pour the sand into the bottle.
We made three bottles for different colors of sand, so repeat these steps as needed.
Step 3: Making the Structure
This structure is to hold to bottles while the sand flows out.
We cut the dowels to the length we wanted, which was 17 inches. We did this so we could experiment with different lengths of string, and how it effects the patterns of sand.
We duct taped two dowels on each side of the box, making a X with them, with the X closer to the top. This X is what holds another dowel across the box. (picture 1).
We then wrapped string around the X, and then duct taped it to make sure it was secure. (pictures 1 and 2).
After this, we placed a fifth dowel across the structure, laying horizontally to the box. To secure this, we also wrapped string around it, and then duct taped it. (pictures 3 and 4).
Step 4: Hanging the Bottle
For our project, we needed to test the effects of different lengths of string on the patterns drawn with the sand. We found that with a longer string, the patterns were clearer because the longer string caused it to move more gradually. Also, with a shorter string, when the sand landed in the box, it would bounce up and spread out more, making a design that was unclear.
Once the structure was secure, we hung the bottle full of sand on the structure.
Since we had 3 bottles of sand, we chose the lengths 1.5, 3, and 4.5 inches to hang the bottle at. These were measured from the base of the box to the cap of the bottle.
Once we found our desired length, we held it at the length and tied it around the dowel horizontal to the box. In picture 1, we tied the bottle at 4.5 inches.
Step 5: Playing With the Pendulum
After the bottle is hung, it is now time to play with the sand pendulum.
First, we took the tape off the bottle cap, and held one finger over the hole so when we turned the bottle over, no sand would come out.
Next, we pushed the bottle in either a circular or linear motion. To get a result like in the above picture, we swung the bottle in a circular motion, by pushing the bottle in a semi-circular motion.