Can you please help me solve this lab:

Design an item no bigger than a 35 mm film conatiner that will float at the 400 ml mark in a 1000 mL graduated cyllinder with 800 mL of water in it. The item can only be made from "trash", recycled items and common household goods like paper clips, rubber bands, ziplock bags, balloons, etc.
I'm trying to perfect putting paper clips into a balloon, but it's hard. Does anyone else have other ideas on how to make this work? Other than the balloons I've tried putting things like paper clips, staples, beads, etc. in the film container so the container will float and the other material will make it sink, but I've tried for hours and it's hard to perfect these. Any other suggestions?

To design an item that will float at the 400 ml mark in a 1000 mL graduated cylinder, you can use the following steps:

1. Start by gathering the materials you have mentioned, such as paper clips, rubber bands, ziplock bags, and balloons.
2. Take a ziplock bag and seal it tightly, removing as much air as possible.
3. Attach a rubber band to the ziplock bag, making sure it is secure.
4. Next, fill the ziplock bag with an appropriate amount of water to make it sink.
5. Attach paper clips to the rubber band, adjusting the number of paper clips until the desired buoyancy is achieved.
6. Test the ziplock bag in a separate container filled with water to see if it floats at the desired level. Adjust the amount of water or the number of paper clips as needed.
7. Once you have perfected the buoyancy of the ziplock bag, transfer it to the 1000 mL graduated cylinder with 800 mL of water. The ziplock bag should float at the 400 ml mark.

If you are having difficulty with putting paper clips into a balloon, there are alternative methods you can try. Here's an alternative suggestion using the materials you have:

1. Take a balloon and partially inflate it, leaving enough space for additional items.
2. Insert a small ziplock bag filled with enough water to make it sink into the partially inflated balloon.
3. Place paper clips inside the ziplock bag, adjusting the number until the desired buoyancy is achieved.
4. Complete inflating the balloon to its desired size, making sure the ziplock bag with paper clips is in the center of the balloon.
5. Test the balloon in a separate container filled with water to see if it floats at the desired level. Adjust the amount of water or the number of paper clips as needed.
6. Transfer the balloon to the 1000 mL graduated cylinder with 800 mL of water. The balloon should float at the 400 ml mark.

Remember, it may require some trial and error to achieve the perfect buoyancy. Be patient and try different variations until you get the desired result.