name______J#_____
Thermal Energy Lab-MS Credit Answers
Testable Question
How does the amount of matter affect the transfer of heat in a substance?
BACKGROUND
As you have discovered, there are many forms of energy. One form that is commonly found is Thermal Energy, or heat. Different forms of energy can be transformed to other forms, but according to the Law of Conservation of Energy, energy cannot be created or destroyed. Energy is simply transferred to another form. For example, when electrical energy travels through a light bulb, the filament in the bulb is heated (thermal energy) and gives off light (electromagnetic energy). Cooling is the transfer of heat into the atmosphere as the heat source RADIATES that heat. In this activity, you will compare the speed of the transfer of heat energy as it relates to the energy applied to different amounts of matter.
Different concepts addressed in this activity: Thermal Energy Transfer (convection, conduction, radiation), Energy conversion, states of matter, and change of state.
HYPOTHESIS (Use the Testable Question)
MATERIALS
hot plates (1) beakers- 4 made of the same material water
thermometers (3) safety goggles stopwatches 2 hot pads
colored pencils
PROCEDURE
1. Put on your safety goggles.
2. Gather three 600 mL beakers
3. Heat 800 mL of water on the hot plate using the 1000 mL beaker (or flask) until it comes to a boil. Turn off the hot plate.
4. Pour 500-mL of the hot water into beaker A. Set it on the table on a hot pad or paper towel.
5. Pour 300-mL of the hot water into beaker B. Set it on the table on a hot pad or paper towel.
6. Pour 100-mL of the hot water into beaker C (I drew a line). Set it on the table on a hot pad or paper towel.
7. You need three students to do this part. Each student puts a thermometer into beakers A, B, or C. Do not stir the water. Leave the thermometer in the water without moving it for the entire time you are collecting temperatures. Beginning at the same time, each student measures the initial temperature of their beaker in degrees Celsius. Enter the data in the table.
8. Record the temperature in each beaker every 30 seconds for eight minutes. Do not stir the water.
9. Calculate the amount of heat lost (transferred to the air) for each beaker.
SAFETY CONCERNS
1. Wear safety goggles AT ALL TIMES during lab.
2. Use extreme caution when working with hot plates! DO NOT TOUCH THE BEAKERS WITHOUT GLOVES OR HOT PADS!!!!!
3. Never leave the hot plate unattended.
4. Turn off, then unplug the hot plate when not in use.
5. Push back long sleeves and tie back long hair.
6. Do not use chipped or cracked glassware.
7. Notify your teacher immediately if an accident occurs.
8. Hot liquids and steam can burn just as badly as the hot plate. Use extreme caution when pouring!
9. Glassware can become extremely hot. Never touch heated glassware with your bare hands.
While the water is being heated on the hotplate…..
Thermal Energy is the total amount of kinetic energy of all the particles in a solid, liquid, or gas.
Temperature is the AVERAGE amount of kinetic energy of the particles in a solid, liquid, or gas (measured).
Thermal energy is dependent on mass, whereas temperature is not. For example, I have a glass of water that is the same TEMPERATURE as a lake. Which has MORE thermal energy? ______
This is because the number of water molecules in a lake are much much greater than the number of water molecules in a glass of water.
Now…what if that glass of water was hot? Does the lake still have more thermal energy? ______
If you said yes, you are correct. Size matters when it comes to thermal energy! Temperature is simply a measure of the AVERAGE movement.
Heat is the flow of thermal energy as it moves from warmer regions to those that are cooler. Heat is transferred through radiation (through waves or initial transfer of heat from a source), then through convection (transfer of heat through liquids and gases) or through conduction (transfer of heat through direct contact).
Use this to check your HW answers:
Term for heat transfer / Example of Sun’s energy / Earth exampleRadiation (initial transfer) / Sun radiates heat through electromagnetic waves was they move though the gases of the atmosphere. / Warm your hands by the campfire which is radiating heat.
Convection (transfer through liquids and gases) *fluids / The Earth is unequally heated so the air heated by radiation begins to transfer heat from warm air to cooler air (heat always moves from hot to cold). / While sitting by the campfire, the air warmed by the fire transfers its heat to the cooler air making it tolerable for you to sit there!
Conduction (transfer through direct contact) / As the radiation warms the sand at the beach, you decide to walk on the sand. Through conduction, your feet are now hot! / As the fire warms your marshmallow stick through radiation, not thinking you touch the metal. It conducts the heat to your hand which is now hot!
OBSERVATIONS/DATA
Time (min) / 400-mLTemp. (Celsius) / 200-mL
Temp. (Celsius) / 100-mL
Temp. (Celsius)
Initial / 75 / 75 / 75
0.5 / 75 / 75 / 74
1.0 / 75 / 74 / 73
1.5 / 74 / 74 / 72
2.0 / 74 / 73 / 71
2.5 / 74 / 73 / 70
3.0 / 73 / 72 / 69
3.5 / 73 / 72 / 68
4.0 / 73 / 71 / 67
4.5 / 72 / 71 / 66
5.0 / 71 / 70 / 65
5.5 / 71 / 69 / 64
6.0 / 70 / 68 / 63
6.5 / 70 / 67 / 62
7.0 / 69 / 66 / 61
7.5 / 69 / 66 / 60
8.0 / 68 / 65 / 59
Amount of Heat Lost
8.0 min. temp – Initial temp
RESULTS/GRAPH
What kind of data is this? CONTINUOUS SO, what type of graph? TRIPLE LINE GRAPH Be sure to use an informative title for your graph, include the correct axes labels with units, and include a key for your graph (where your test variable will be because there are 3 lines). *GRAPH 1 line at a time so you do not confuse data.
What was your Test Variable? Amount of Matter (liquid) * This is placed as the KEY for your graph on a line graph….3 lines, three trials of gathering data. Outcome Variable? Temperature
Name 2 constants that you used? Initial Temperature, beaker size and material, time intervals
EVALUATION/ANALYSIS/CONCLUSION
1. Was there a relationship between the amount of matter and how quickly heat was transferred? YES
If so, what is the relationship? The larger the body of water, the longer it takes for the heat to transfer out of the water.
2. Which container lost or transferred heat energy the fastest? Why do you think this happened? Refer to page 2 of lab…
The smallest amount of matter (Beaker C – 100 mL of water) lost thermal energy the fastest because it had the least amount of water (matter) to start with, thus the least amount of thermal energy quantifiably speaking. * The total kinetic energy of moving particles of matter is calledthermal energy.
3. Where did the Thermal Energy go (where was it transferred to) and WHY? Explain….don’t just answer with one word.
The thermal energy was released into the air (steam or vapor), to the table, to the thermometer, and to the glass beakers. The heat became all unusable thermal energy.
4. In the famous story of Goldilocks and the Three Bears, Goldilocks tried the porridge from three different sized bowls. She found the largest bowl, Papa Bear’s bowl, was too hot. She found the medium sized bowl, Mama Bear’s bowl, to be too cold. Eventually, she ate from the smallest bowl, Baby Bear’s bowl, because it was neither too hot nor too cold. It was “just right.” Assuming all other variables were constant (controlled), is this scientifically possible? Explain. Be sure to include evidence!
• Beaker A was the hottest…and remained the hottest (like Papa Bear’s bowl) because it was the largest amount of the substance, The heat (Thermal Energy) that it took in (it took in the most), transfers back into the atmosphere (cooling) over the longest amount of time….because it is the largest.
• Beaker C was the coolest. It was the smallest (like Baby Bear’s bowl), so therefore it loses its heat the fastest. This contradicts the story where Baby Bear’s is just right.
• Beaker B was in the middle of the two temperatures because it is in the middle in size as well. This contradicts the story where Mama Bear’s is too cold. This is not possible. The smallest amount of mass will always cool the fastest because it contains the LEAST amount of matter AND therefore, the least amount of energy.
– Think Hot Cocoa Pot vs. small mug
5. Not sure if you noticed or not, but though you poured a set amount of water into each beaker, at the end of class each beaker contained LESS water than you originally poured (particularly the large beaker). Where did the water go? …and WHY? *think change of state….
Even after the beaker was moved from the heat source, the temperature of the water stayed at 100 degrees Celsius for a bit and continued to change state from liquid to gas. Once the temp fell too far below 100 degrees, it no longer evaporated.
6. In the lab, what provided the radiation? Hot plate-Initial heat transfer.
Where was there conduction? The hot plate to the beaker, beaker to the water, if you touched the beaker conduction was between beaker and hand, water to thermometer, beaker to table. Any solid transferring that initial heat!
convection? In the beaker, heat rising, cool falling all within the water, air also circulated and the energy transferred from hot to cool there as well.