writing a hypothesis---

how many pounds of weight can be held by a bridge made out of 30 Popsicle sticks.

normally, a hypothesis will test or compare something to a control. If you have one bridge, which you have designed and build, here are some examples

Bridge will hold a 65 lb weight suspended from the center for 456 seconds.

now that is really not much to brag about, as if the bridge fails, you have learned nothing. So I would conduct the experiment in stages, noting the weight.
start of with 10 lbs, note results.
then add 10, note results, and so on.

At least you will get to a point of failure and you know the limit, or you will get to 456 lbs and declare success of your hypothesis test, and go celebrate by buying a round of popsicles.

A better hypothesis would be to compare two bridges designed differently. Such as

The span bridge will hold more weight than the XXXX bridge given the same bridge weight.

To write a hypothesis for your question, you need to formulate a clear statement that predicts the relationship between the independent variable (the number of Popsicle sticks) and the dependent variable (the weight capacity of the bridge).

Here's an example hypothesis you can use as a starting point:

"Holding all other factors constant, increasing the number of Popsicle sticks in a bridge will result in a higher weight capacity."

Now let's discuss how to determine the weight capacity of the bridge made out of 30 Popsicle sticks.

To calculate the weight capacity, you need to consider the strength of individual Popsicle sticks, their arrangements, and the adhesive you are using to hold them together. Here's a step-by-step guide on how to determine the weight capacity:

1. Research: Look for information on the average weight-bearing capacity of a single Popsicle stick. This can vary depending on the specific material and dimensions of the sticks you are using.

2. Assess bridge design: Consider the arrangement and structural design of your bridge. Are you building a basic truss bridge or using a more complex design? A truss bridge tends to distribute weight more effectively compared to a simple flat bridge made of stacked sticks.

3. Calculate total area: Measure the dimensions of a single Popsicle stick and multiply these measurements by the number of sticks used (in this case, 30 sticks). This will give you the total area of the bridge in square inches.

4. Determine weight per square inch: Using the information from your research, calculate the weight per square inch that a single stick can bear. Multiply this value by the number of sticks in your bridge to find the total weight capacity.

Keep in mind that this calculation is an estimate and may not account for all the variables affecting the bridge's strength, such as the quality of the sticks or the skill of the assembly. It's also important to note that a hypothesis alone cannot determine the exact weight capacity, but it serves as a starting point for further investigation and experimentation.