Science Buddies: "Ask an Expert"

Hi, I am doing a science fair project growing seeds of the same plant with varying levels of radioactive water....heated in the microwave. I will have a control with plain distilled water. Three others with water heated in the microwave for different times each to heighten the degree of radiation in each cup of water. How will the radiation affect the growth of the plants? How long should each amount of time be?


Thank you,
Aidan Peake
Vanguard Prep 7th grade science

HI,

This sounds like an interesting project. I want to make sure you understand some of the terms you are using. Microwaving water does not render it radioactive. In fact, radioactivity is not something you can handle in your lab - you need special safety equipment in order to do it. Microwaving water exposes the water to ionizing radiation, which is essentially heat. I think you will find this article interesting, and you should start your research project here: http://blogs.mcgill.ca/oss/2012/03/30/w ... the-plant/

You can still do this project, but the hypoethesis is that you expect to see no difference in this or plain unheated water.
Your experiment could look at times from a few seconds to a few minutes... either way, let the water cool before you add it to the plants... and we expect no difference in the plant growth.

Please let me know if you have any questions.

Tonya

Hi Aidan,
Like Tonya mentioned, although a microwave does give off very small amounts of radiation (not enough to harm you!), microwaving water does NOT make it radioactive...that would be very concerning. You're probably wondering why. microwave radiation is composed of electrical and magnetic energy that is absorbed by the water molecules. When water molecules gain energy they speed up. The temperature of a substance is actually determined by the movement of the molecules making up that substance. That's why when something is frozen, it becomes solid, and if it is heated enough it melts and liquidizes. The solid's molecules are vibrating, tightly together, while the liquid's molecules are moving about, bouncing off of each other. The more energy molecules gain from heat, or radiation etc.., the faster they move, and the warmer the substance becomes. So, when your water is exposed to microwave oven radiation it doesn't become radioactive. It simply gains energy by absorbing the radiation emitted, the water molecules speed up, and wow your cup now feels like the edge of a hot tub.

On a side note, I agree with Tonya. You could still totally do an experiment with this although there is already data out there on the effects of varying water temperatures on plant growth you should go find out for yourself. For your hypothesis, what do you think? Why or why not do you think temperature affects plant growth? Check out the science buddies project guide if you're still a bit confused about constructing a hypothesis. Here's a link to the key info.....https://www.sciencebuddies.org/science- ... esis.shtml
Your hypothesis could look something like this: "If I place plants in waters of varying temperature for (insert amount of time), then the plants growing at (insert temperature) will (insert predicted result)". Good luck on your experiment! You've piqued my interest! Please tell us how your results turn out and make sure to have a good number of controlled variables in your experiment to avoid any sketchy data.