I need to find an object that will sink to the bottom of a glass of water, then rise to the surface within 30 seconds. I can't find that object!!

what about a glass vial with a bit of baking powder in it?

how do you know what to do for a science project?

To find an object that will sink to the bottom of a glass of water and then rise to the surface within 30 seconds, you can try experimenting with various objects. Here's a step-by-step approach to help you find the desired object:

1. Collect a selection of small objects that you think may have the properties you're looking for. Examples could include small plastic toys, marbles, coins, or rocks. Ensure they are clean and dry before testing.

2. Fill a glass with water, leaving enough space at the top for the object to rise to the surface.

3. Test each object individually by dropping it into the water and observing its behavior.

a. If the object quickly sinks to the bottom but doesn't rise back up within 30 seconds, remove it from consideration.

b. If the object floats or stays near the surface, it won't fulfill your requirements.

c. If an object initially sinks to the bottom but then rises to the surface within 30 seconds, you've found what you're looking for.

4. Repeat this process with different objects until you find one that behaves as desired.

Remember, the specific properties of an object that allow it to sink and then rise within 30 seconds depend on its size, density, and shape. It may require some trial and error to find the right object that meets your requirements.