Activity: Investigating the First Law of Thermodynamics
Grade Level: 12 STEM
Topic: First Law of Thermodynamics
Objective:
Demonstrate an understanding of the First Law of Thermodynamics.
Analyze energy transfer in a simple system.
Apply the concept of conservation of energy in real-life scenarios.
Activity Title: "Hot or Not? Tracing Energy Transfer"
Materials (per group):
✅ Metal cup or small beaker
✅ Thermometer
✅ Hot water (~70°C)
✅ Cold water (~10°C)
✅ Insulated container (or Styrofoam cup)
✅ Stopwatch
✅ Graphing paper or spreadsheet software
Procedure:
1. Predict – Before starting the experiment, predict what will happen to the
temperatures of the hot and cold water when mixed. Write your hypothesis.
2. Prepare the Setup –
o Fill a beaker with 200 mL of hot water (~70°C).
o Fill another beaker with 200 mL of cold water (~10°C).
o Record the initial temperatures of both.
3. Mix the Water –
o Pour both into an insulated container and quickly insert the thermometer.
o Record the temperature every 30 seconds for 5 minutes while stirring gently.
4. Analyze the Data –
o Plot a graph of temperature vs. time for the mixture.
o Calculate the heat lost by the hot water and the heat gained by the cold water
using:
5. Discussion Questions:
o How does your data support the First Law of Thermodynamics?
o Did the heat lost by the hot water equal the heat gained by the cold water?
Why or why not?
o What are possible sources of error in your experiment?
o How does this experiment relate to real-world applications like thermal energy
storage or engine efficiency?
Worksheet: Investigating the First Law of Thermodynamics
Name: ______________________
Group Members: ______________________
Date: _______________
Grade & Section: _______________
Part I: Prediction
Before conducting the experiment, answer the following:
1. What do you think will happen to the temperatures of the hot and cold water when
mixed?
2. How does this relate to the First Law of Thermodynamics?
Part II: Data Collection
Time (s) Temperature (°C) of Mixture
0
30
60
90
120
150
180
210
240
300
Part IV: Analysis & Discussion
1. Based on your calculations, did the heat lost by the hot water equal the heat gained by
the cold water? Explain any discrepancies.
2. What factors may have affected the accuracy of your results?
3. How does this experiment demonstrate the First Law of Thermodynamics?
4. Can you think of a real-life example where energy is conserved in a similar way?
Rubric for Assessment
Needs
Criteria Excellent (10 pts) Proficient (8 pts) Basic (6 pts) Improvement (4
pts)
Clear, well-thought- Prediction Prediction is
Prediction & out prediction based provided but vague or lacks No prediction
Hypothesis on scientific lacks strong connection to the provided
reasoning reasoning concept
Accurate and
Data Mostly accurate Some data missing Little to no data
complete data
Collection with minor gaps or inconsistent recorded
recorded in table
Minor errors in
Correct calculations Some errors in Incorrect or
Heat Transfer calculations but
with clear steps and calculations missing
Calculations mostly correct
explanations affecting results calculations
reasoning
Thorough answers
Answers Answers are brief
with deep
Analysis & provided with with limited Incomplete or
understanding and
Discussion some real-world connection to missing answers
real-world
applications concepts
connections
Well-organized, Organized but Somewhat Disorganized,
Overall
clear, and neatly with minor clarity disorganized, hard incomplete, or
Presentation
written responses issues to follow messy
Total Score: ____ / 50
