Science Buddies: "Ask an Expert"

My science fair project looks at whether plants are negatively or positively affected by sound. I created a sound proof environment by gluing plexiglass to cardboard, then placing paper on top of the plexiglass to prevent the plexiglass from harming the plants. These pieces of cardboard were taped together to create a box, only entered by a duct tape hinge on the top of the box. However, when I placed the plant light inside the box, the top of the box is uncomfortably close to the cover of the box. In fact, the paper received a little burnt mark. How can I save my project from burning and rebuilding new boxes? What can be placed on either the bulb or the top of the box to prevent over-heating?

Hi,

Even though your project is technically a life sciences project, I think your question is better asked in the physical sciences forum so I've moved it there.

My initial reaction, though, is to say that the plexiglass shouldn't hurt your plants, so you can take the paper out from inside the box. Is the cardboard inside or outside of the plexiglass?

You might also consider using a smaller/lower energy bulb (but all plant lights might be high-energy) or rigging the bulb to be further away from the paper/cardboard. But, as you've figured out, you need to be really careful with this because there is obviously a fire hazard.

Hopefully the physical scientists can help more!

Your design is basically an oven. You sealed your container so that there is very little air flow. You insulated your sealed container (your sound proofing acts as thermal insulation). You put a heat source inside the insulated container. You have an oven with combustable materials inside. To reduce the fire risk, just remove the combustable meterials from near the heat source.

From a scientific investigation standpoint, I suspect you have a bigger problem and you need to rethink your project in terms of determining how you are going to provide a good environment for plants to grow where the only difference between the control group of plants and other groups is the sound.

Controlling temperature, moisture, humidity, O2 / CO2 percentages, are probably some of the things you need to think about.

You may have to compromise on the sound proofing to satisfy controlling other requirements. Something you might consider is making your chambers into "chimneys" where air can circulate in through the bottom and out through the top. If you make several sound damping baffels in these paths you can still have air flow and come close to the same sound proofing levels.

Thank you so much for your response--I'm sorry it took me so long to reply. Unfortunately, I had already bought the supplies for the plexiglass, so i couldn't start over. However, even though this is my first and last science fair project, it was wonderful thanks to your help and suggestions!