Physical Science Institute

Physical Science Institute

Summer 2013

Degrees of Separation

Teacher Guide

Note: This guide only contains sample data for the first trial in part 2

MATERIALS per 3 person group

1 Temperature ProbeLabQuest2Beaker

Hot PlateStyrofoam cups100 ml graduated cylinder

Vendor / Description / Item Number
Fisher / Scale, top-Loading / S94792K
Fisher / Graduated Cylinder / S31857
VERNIER / LabQuest2 / LBQ2
VERNIER / Temperature Probe / TMP-BTA
Fisher / 250 mL beaker / S30730-6
Fisher / Hot Plate / 11-100-16H

SAMPLE DATA

Data Table 1

Part One / Mass / Initial Temperature / Final Temperature
Cold Water / 40 g / 23.6 °C / 31.9 °C
Warm Water / 40 g / 40.2 °C / 31.9 °C

Data table 2

Part 2 / Mass of
Warm Water / Initial Temperature (Warm water) / Mass of Cold Water / Initial Temperature (Cold Water) / Final
Temperature / Decrease in Temperature (Warm water) / Increase in Temperature (Cold Water)
1 / 60 grams / 39.9°C / 30 grams / 26.6 °C / 35.3°C / 4.6°C / 8.7°C
2 / 80 grams / 20 grams
3 / 60 grams / 12 grams

CALCULATIONS & RESULTS

Calculate the increase and decrease in temperatures and record in Data Table 2.

PART 1:

1. What was the temperature increase of the cold water? 8.3 °C

2. What was the temperature decrease of the warm water? 8.3 °C

3. What is the ratio of the warm water temperature decrease to the cold water temperature increase?

8.3/8.3 = 1

Share this on the data table on the board.

4. How does this compare with the group?

PART 2:

1. Calculate the ratio of the warm water to the cold water. Record in table below.

2. State the reciprocal of the ratio of masses. Record in table below.

3. Calculate the decimal equivalent of reciprocal of ratio of masses. Record in table below.

4. Calculate the ratio of the temperature changes (decrease/increase). Record in table below.

Trial / Ratio of
Masses
(Warm/Cold) / Reciprocal of
masses / Decimal
Equivalent of
Reciprocal / Ratio of
Temperature changes
(decrease/increase)
1 / 2 / ½ / 0.5 / 4.6/8.7 = 0.53
2 / 4 / ¼ / 0.25
3 / 5 / 1/5 / 0.2

Which of the two masses underwent the larger temperature change (the larger or smaller mass)?

smaller

How does the decimal equivalent of the reciprocal of the masses compare to the ratio of temperature changes?

They are the same.

Is there a relationship between the warm water mass and temperature decrease, and the cold water mass and its subsequent temperature increase? Represent this relationship as a mathematical equation.

(Mwarm water)(Tdecrease) = (Mcold water)(Tincrease)

We can now use this product to define the change in thermal energy. With this definition, the increase in thermal energy of the cool water equals the decrease in thermal energy of the warm water. In order to define this as an amount of energy, a unit of energy must be chosen. In this case, the unit is: (g)(Δ⁰C) This is also the definition of the calorie, the standard unit of energy used in food energy.