It's Heating Up!!

For my heat transfer investigation, I used four Styrofoam cups identical in size shape and volume.  Square pieces of bubble wrap, aluminum foil, newspaper, and Styrofoam were used as the insulating materials. 250 cc of hot water was added to each cup.  A starting  water temperature of  46°C provided me with a benchmark to be used in determining the best insulator.  Each was secured with a rubber band, except for the Styrofoam. That was secured by a few pebbles.  Temperatures was taken after 30 minutes. Results are shown in the table below.

  

Type of Insulator Material	Temperature in Celsius
Aluminum Foil	43
Styrofoam	44
Newspaper	41
Bubble Wrap	44

As seen in the table above the bubble wrap and the Styrofoam exhibited the least amount of heat loss, while the newspaper exhibited the most.  As a side note, the bubble wrap had the "bubbles" intact.  Conclusion: The bubble wrap was just as effective insulator as the Styrofoam. The bubble wrap and the Styrofoam have many small air spaces.  These small spaces make the molecules less likely come in contact with other molecules to "pass on" the increased vibrating motion (Tillery, Enger and Ross, 2208).

If I was to repeat this experiment, I would include a second part to this investigation.  The second part  would focus on the amount of temperature change and would consist of  changing the type of drinking container. Instead of a Styrofoam container using a "coffee mug" while keeping the insulating materials, and the amount of water the same. What would be interesting to find out if there was more of a heat loss with a ceramic coffee mug than with a Styrofoam cup.

If I were to plan an engaging scientific inquiry for  my 4th grade students on heat transfer, it would be centered keeping a meal warm, similar in the article "What's Hot What's Not?" with a little variation. Inquiry would be of a guided one initially. The manipulated variable in the experiment would be the type of bowl used to  keep a select piece of food warm. The type and amount of food would remain constant.  A benchmark temperature would be taken, then at preselected intervals to track heat transfer among the bowls. Results would be graphed.  After the investigation  each student group would initiate questions  that may lead them to develop their own investigations.

 

 

Guided Inquiry: Pendulums

For my guided inquiry experience this week illustrating the concept of momentum, I chose the question, "Which pendulum will come to rest more quickly, a lighter or heavier pendulum?"  Before actually carrying out the experiment,  basic information was gathered about simple pendulums. Many variables came into play. They ranged from the length of string, weight of the bob and the amplitude or angle or release.  Since the question pertains only to mass, the string and amplitude were the fixed variables.  The materials used in the investigation was a yardstick, a protractor, fishing line and the three washers from the science kit. Each washer was given three trials. Time was entered in a data table.  Results showed that the heavy washer came to a full rest  averaging around nine  and a half minutes after it's release. the light weight washer four and a half and the medium weight  washer close to seven minutes. The investigation, yet simple, demonstrated the concept of momentum and the objects having more mass, momentum increases.

What worked well or did not work well? The materials were  simple and readily available. the pivot point game me issues.  I first used a pushpin as the pivot point of the pendulum. There was a lot of movement at the pivot point causing the washers to fall off on several occasions. A thumbtack replaced the pushpin causing less movement at the pivot point. Modifications to the investigation might include changing the amplitude, arc, of release of the pendulum. "Will that cause increased momentum and therefore causing the bob to take longer to come to a complete rest?
 
Engaging  and relevance, two interesting vocabulary words. To understand pendulums better take the students to a  field trip to a playground with a swing set. Once there, the students observe their fellow classmates on swings with various lengths.  Observing  the different mass of each of the students and how that might affect the frequency and  period of the pendulum as well the arc or amplitude of release.  A totally different activity, if your principal or supervisor allow, is sledding. Children of different mass sledding downhill using different sleds.  There are many concepts and variables that come into play here, momentum, friction, gravity, etc. 

Specifically having the students understand and learn the workings of a SIMPLE pendulum, collecting and analyzing and the ability  to generate conclusions from that data. Challenging my students to come up with variables  affecting the period and frequency of a pendulum would be a goal in achieving further understanding of how pendulums work.