Science Buddies: "Ask an Expert"

I am doing a project on the effect color has on the melting times of ice and I don't know where to begin with the research. I really need help in getting this project started because I am a bit lost. My project is due at the end of March early April and I need help!

From Kyle

Hi!
This sounds like a cool idea! I think one of the most interesting ways to approach this is by altering the color with other chemicals. Certain substances, when added to water, change the color of the water, which you can ultimately freeze to make into ice (making sure to keep track of how much water you originally used to make the ice). For example, this video might give you some ideas to start off:
http://www.wonderhowto.com/how-to-color ... nt-271161/
In terms of measuring the melting rate of the ice, you can place each block of ice into an empty beaker. You can then use a stopwatch to monitor how long it takes for each block of ice to melt. To make sure that all the ice has indeed melted, refer back to the measurement of the original amount of water you had to begin with. Feel free to add your own creativity, have fun!

staryl13 wrote:Certain substances, when added to water, change the color of the water,

Anything you add can affect the temperature at which liquid<->solid state changes occur and the "heat of fusion". Read up on "heat of fusion" and "freezing point depression".

Good examples of this are antifreeze, Sodium Chloride, a Potassium Chloride which are used to treat roads in snowy /icy conditions.

Eliminating the possibility of freezing point changes and heat of fusion differences between different colored samples because of different chemicals properties of the dyes you use affecting your results more than any color difference may be difficult.

Any hypothesis that states some "color" of water might behave differently makes some assumptions on light properties. If you do your test in a completely dark chamber with a radient heat barrier, the results might be significantly different than in a different enviornment.

Read up on the electromagnetic spectrum and radient heat. Light energy (and radient heat energy) have reflective and transmittance properties at all boundaries. Different chemicals have different spectral behaviors as well. Whether some interaction occurs at any given wavelength will depend both on their being a light/heat source at that wavelength and the reflective and transmittance properties of the material's spectrum at that wavelength.

A different approach might be to come up with different colored containers (opaque or translucent). You could use a digital camera that has manual shutter/aperature controls as a way of measuring reflectance and transmittance in the visible light spectrum to eliminate or calibrate for differences in the materials.

Figuring out how to make fair measurements in this kind of a project will be challenging.

Hey,

I agree with Craig; depending on the set-up, this experiment can be either chemical or physical in nature.

If the experiment is done in a dark chamber, then the results may be based on how the coloring agent affects the chemical make-up of the ice and how that impacts melting.

If the experiment is done in the presence of light, the color of the ice will affect how much light is absorbed, and therefore how much heat.

The problem with the 2nd experimental setup is how to control the light. If you plan on doing that, you may want to use a dark room with a light bulb? Or some sort of light source that is constant and NOT variable.