“Heating Things Up”6.5.2: Evaluate Precision and Usefulness of data based on measurements taken. By Emily Weil 10/07/09 Content from:
Definitions Precision- accuracy; exactness. Heat- added or external energy that causes a rise in temperature. Energy- source of power; ability to act, cause an effect, etc. Hypothesis-A tentative explanation for an observation, phenomenon, or scientific problem that can be tested by further investigation. Experiment- research; investigation (try different ideas to test a hypothesis). Procedure- following a particular series of steps; a process. Degree(s)- unit of measure of temperature (Celsius). Taken from Dictionary.com and the Indiana State Science Standards
Why are precise measurements important? Sometimes estimation is a good idea, but is that true in every case? Consider the following: Maria is running a temperature of 100.6 Degrees. The normal human body temperature is 98.6 Degrees. Many would look at this and say that her temperature is not that far off. However, a temperature of 100 is considered a fever and severe. The human body’s temperature does vary slightly, but at most only 1 Degree. Would rounding be a good idea? 101 is basically 100 isn’t it?
The Experiment Okay, here’s the breakdown of the experiment: We are using the idea of precise measuring and its importance with temperature. The sun produces heat, correct? Objects absorb the heat from the sun’s light. Do all objects absorb the same amount of heat at the same rate? *Does color play a part in this? Does it make a difference?
Gather the required materials 3 or more cans that are exactly the same. (soup cans work well) Black, White, and any other color paint you desire to test. Paintbrushes Lamp with a 60 watt light bulb Ruler, or other measuring device Thermometer Measuring Cup/Beaker Water
How Should You Begin? What will your procedure be? How will you make sure you do each can the same way? Here’s an example! (Be precise! Make sure you know every measurement possible!)
Paint the cans Paint one can white, one can black, and if you decide to test any other colors, then paint another can that color. Leave one can without paint!!! *To be precise, make sure each can is identical (before it’s painted)
Next Step If you test each can at the same time (best idea), make sure you do each the same way: Measure out equal amounts of water for each Take the temperature of the water in each before you turn on the light. Measure how far away you put the lamp so that you can put it an equal distance from each can. Make sure you don’t lose track of time! (Redo the whole thing if you forget because you want your data to be EXACT!!!!
How will you record your data? Design a clear and concise way to record your data (keeping in mind that you need to experiment the same way each time) Will you include a picture, or drawing? What will you measure and how often?
For an example Black Line Master on a way to record your data, go to:http://www.indianastandards.org/files/sci/sci_6_5_2.pdf.
What were your results? Record your results (Keeping them as precise and accurate as possible: DON’T ESTIMATE!) What did you find? Which color can absorbed the most heat? How could you tell? What did the temperature tell you? Think About It!
Findings Okay, here’s some explanation for what you should have found. The water inside of, or touching, the black can should have shown more of an increase in temperature over time. Why? Black absorbs all colors of light, and thus heat. White reflects all colors of light, so it does not absorb that energy and does not cause the water inside of the can to increase in temperature.
Apply What You Know! Okay, so now you’ve discovered that different colors absorb light and heat at different rates. (Black being the best at absorbing the sun’s heat) How can you use this idea? Have you ever heard of solar power? Well, some people have made devices called solar powered pizza box ovens. Do you think that knowing what absorbs heat quickly would help with that experiment? Design a pizza-oven (solar-powered) using what you’ve discovered in this experiment!