My PBL Project

Introduction -

Our driving question is what happens when you wrap rubber bands around a watermelon? The main topic of our PBL project is pressure, and we hypothesize a large amount of rubber bands will constrict the watermelon rind causing pressure to build up. Pressure from the rubber bands causes the watermelon to crack open, which releases the pressure.

Materials -

• • Watermelon

  • Rubber bands

Procedure -

• 1. Place the watermelon on a flat surface.

  2. Begin to place the rubber bands around the watermelon, try to keep them centered in the middle.

  3. Continue to place the rubber bands around the watermelon until the watermelon bursts.

  4. Record how many rubber bands were placed around the watermelon.

SAFETY:

We recommend using gloves to protect your hands from the rubber bands and using safety glasses in the possible chance that the watermelon bursts near you.

Pictures and Action Video -

Scientific Principle -

The scientific principles behind our project are kinetic and potential energy. There is potential energy in the rubber bands, once they are stretched around the watermelon they gain potential energy. The potential energy in the rubber bands becomes kinetic energy when all the rubber bands are released into the air after the watermelon bursts.

Observation -

We observed the watermelon burst, as it got very close to bursting the top seemed to swell up.

Conclusion -

Our conclusion is that the pressure built up from about 550 rubber bands caused the watermelon to burst.

Real Life Application -

One scientific principle we are choosing to focus on is potential and kinetic energy. There a lot of real life applications we can think of that deals with this exact concept. For example, there is potential and kinetic energy when we throw a ball, when cars are getting ready to go on a green light, and one we all know, roller coasters getting ready to descend from the highest peak. Through these many example one way this idea benefits our society is by allowing us to advance in multiple ways due to how many different ways it can be applied. This also goes hand in hand with how potential and kinetic energy may be utilized for future benefits and applications.

Investigation Questions -

1. What were the indicators of the watermelon about to explode?

The most notable indicator was when the watermelon seemed to swell up as it was being compressed by the rubber bands more and more as time when on. There was also a hissing sound we heard toward the end, as well as juice from the watermelon spilling on the sides.

2. Are there any other scientific principles that help explain this project?

Yes, we can also associate the principle of compression with this topic. Compression is the reduction in volume which causes an increase in pressure. The compression of watermelon caused an increase in pressure which ultimately caused the watermelon to burst.

3. What is energy?

Energy is something that can be found in many things and can be in various formations. There are two basic forms of energy, both of which we already mentioned and play an important factor in our project: kinetic and potential energy. Put simply, energy allows us to do work.

4. When is energy released in this project?

We can see two examples of energy in this specific project. The first occurrence is when energy is released when the watermelon explodes, releasing built up energy. The second is when the rubber bands snap back from their position of being stretched.