Thermal Energy: Hot or Cold

ACTIVITY SET A: Thermometer, water, wood block, metal object.

#1   Examine a thermometer. What part is the bulb? What part is the tube? Make a drawing of the thermometer with labels. What happens if the liquid inside gets hotter? What happens if it gets cooler?

#2 Obtain a wood block and a metal object. Determine the temperature of each by touching each individually to your lip (mouth closed) or inside wrist. If one is in fact colder, it should reduce the temperature of a water sample. Place 100 mL of water in a beaker. Measure the temperature. Add the cold object and observe a change in temperature.
Is touching something a good way to determine if something is hot or cold?
How do we measure the temperature of an object?

#3 Place 200 mL of water in a beaker and record its temperature. Divide
 un-evenly. And determine the temperature of each part. Can we draw a conclusion from this information? What if we were to divide the water into many parts?

ACTIVITY SET B: Thermometer, water, ice, hot plate.

#1 Using a thermometer requires that it be marked. We will be using a Celsius scale thermometer. We will identify the two most important positions. Place the thermometer into a mixture of ice and water. Observe the liquid in the thermometer tube as the water is cooled.  Gently mix while observing the liquid in the thermometer tube. Record the temperature every thirty seconds. When it seems to be staying at the same value continue every thirty seconds for four readings. Graph this data. Explain the graphed data.

#2 Now we will place the thermometer into a sample of water on a hot plate. Observe the liquid in the thermometer tube as the water is heated. Record the temperature every thirty seconds (Caution: The thermometer should not rest on the bottom of the beaker when making readings). When it seems to be staying at the same value continue every thirty seconds for four readings. Graph this data. Explain the graphed data.

Do you think more water would have taken the same time to boil?
Do you think the boiling temperature would have been higher or lower?

Understanding Question: If we were to heat a 100 gram piece of iron so that its temperature increases by 21^oC, by what temperature would 1 gram of the iron increase?

 
ACTIVITY SET C: Thermometer, graduated cylinder, water, hot plate.

#1  Mix equal masses  (cold into hot) of tap water and hot water (less than 60^oC). Be sure to record the initial and final temperature of each. Could you have predicted a final temperature?

#2 Continue to experiment with hot water of different temperature and different masses; predict the final temperature. For our prediction to be true, what procedure/rule should be carefully followed?

ACTIVITY SET D: Thermometer, graduated cylinder, water, hot plate.

We are going to mix hot water with cold water in vary amounts and temperatures.
The starting mass of water should be no less than 25 grams. The temperature of the hot water should be maximum 60^oC.

DATA TABLE

Hot Water                                                                            Cold Water

RESULT TABLE
 

                            Hot Water                                                 Cold Water

Plot a graph of the result table. Determine the slope.

If you mix known masses and temperatures of hot water and cold water, is it possible to predict the final temperature?

Understanding Question: By definition it takes one calorie to change one gram of water one degree Celsius. How many calories are needed to change 40 grams of water by a temperature increase of 20Co? (Hint: Start by thinking how many calories would be needed for one gram of water)

3.1.4 Unifying Themes
 
E. Describe the change to objects caused by heat, cold, light or chemicals.

3.2.4 Inquiry and Design

C. Recognize and use the elements of scientific inquiry to solve problems.

• Generate questions about objects, organisms and/or events that can be answered through scientific investigations.
• Design an investigation.
• Conduct an experiment
• State a conclusion that is consistent with the information.

3.4.4 Physical Science, Chemistry and Physics

B. Know basic energy types, sources and conversions.

• Identify energy forms and examples (e.g., sunlight, heat, stored, motion).
• Know the concept of the flow of energy by measuring flow through an object or system.
• Classify materials as conductors and nonconductors.
• Know and demonstrate the basic properties of heat by producing it in a variety of ways.

BENCHMARCHS FOR SCIENTIFIC LITERACY
 

Chapter 4  THE PHYSICAL SETTING (E) Energy Transformations

By the end of the 5th grade, students should know that:
 

• When warmer things are put with cooler ones, the warm ones lose heat and the cool ones gain it until they are all at the same temperature. A warmer object can warm a cooler one by contact or at a distance.
• Some materials conduct heat much better than others. Poor conductors can reduce heat loss.

Chapter 9  THE MATHEMATICAL WORLD  (B) Symbolic Relationships
 
By the end of the 5th grade, students should know that:
 

• Mathematical statements using symbols may be true only when the symbols are replaced by certain numbers.
• Tables and graphs can show how values of one quantity are related to values of another.