Cambridge Secondary (7-9). Stage 9. MCE Science. Workbook - Unit 10: Transfer of Thermal Energy

Three identical small plastic cups contain equal amounts of hot water, three-quarters full. One cup is wrapped in aluminium foil and insulating material, placed in a larger cup supported by sand, with extra insulation in the gap, a lid and plastic wrap sealing the larger cup. A second cup is uninsulated with a lid; the third is uninsulated without a lid. Thermometer bulbs dip fully into the water. The cups are kept in the same surroundings. Handle hot water carefully; an adult should prepare any holes with a knife cutter.



Measure and record the initial temperature of the hot water. Then use the same amount of hot water to fill the three small cups until they are three-quarters full.

Three identical small plastic cups contain equal amounts of hot water, three-quarters full. One cup is wrapped in aluminium foil and insulating material, placed in a larger cup supported by sand, with extra insulation in the gap, a lid and plastic wrap sealing the larger cup. A second cup is uninsulated with a lid; the third is uninsulated without a lid. Thermometer bulbs dip fully into the water. The cups are kept in the same surroundings. Handle hot water carefully; an adult should prepare any holes with a knife cutter.



Measure and record the temperature of the water in each small cup every 5 minutes for 30 minutes.

| Time in min | 0 | 5 | 10 | 15 | 20 | 25 | 30 |
|---|---|---|---|---|---|---|---|
| Temperature in insulated cup in °C | | | | | | | |
| Temperature in uninsulated cup with lid in °C | | | | | | | |
| Temperature in uninsulated cup without lid in °C | | | | | | | |

Three identical small plastic cups contain equal amounts of hot water, three-quarters full. One cup is wrapped in aluminium foil and insulating material, placed in a larger cup supported by sand, with extra insulation in the gap, a lid and plastic wrap sealing the larger cup. A second cup is uninsulated with a lid; the third is uninsulated without a lid. Thermometer bulbs dip fully into the water. The cups are kept in the same surroundings. Handle hot water carefully; an adult should prepare any holes with a knife cutter.



In groups, discuss: Compare the temperature changes in the three small plastic cups over time.

Three identical small plastic cups contain equal amounts of hot water, three-quarters full. One cup is wrapped in aluminium foil and insulating material, placed in a larger cup supported by sand, with extra insulation in the gap, a lid and plastic wrap sealing the larger cup. A second cup is uninsulated with a lid; the third is uninsulated without a lid. Thermometer bulbs dip fully into the water. The cups are kept in the same surroundings. Handle hot water carefully; an adult should prepare any holes with a knife cutter.



Explain why the final temperatures differed among the three small cups.

Three identical small plastic cups contain equal amounts of hot water, three-quarters full. One cup is wrapped in aluminium foil and insulating material, placed in a larger cup supported by sand, with extra insulation in the gap, a lid and plastic wrap sealing the larger cup. A second cup is uninsulated with a lid; the third is uninsulated without a lid. Thermometer bulbs dip fully into the water. The cups are kept in the same surroundings. Handle hot water carefully; an adult should prepare any holes with a knife cutter.



State three steps you can take to make sure your measurements are accurate and consistent.

Three identical small plastic cups contain equal amounts of hot water, three-quarters full. One cup is wrapped in aluminium foil and insulating material, placed in a larger cup supported by sand, with extra insulation in the gap, a lid and plastic wrap sealing the larger cup. A second cup is uninsulated with a lid; the third is uninsulated without a lid. Thermometer bulbs dip fully into the water. The cups are kept in the same surroundings. Handle hot water carefully; an adult should prepare any holes with a knife cutter.



State three ways to increase your range of observations and measurements to increase your overall reliability and validity of your conclusion.

Attach several drawing pins to a clamped metal rod using small pieces of candle wax. Heat one end of the rod with a Bunsen burner and observe the pins as the rod heats up. Wear safety goggles, tie back long hair and keep a safe distance from the flame. Do not touch the hot rod or falling pins; let the apparatus cool before handling.



Record your observations regarding the drawing pins and the wax.

Attach several drawing pins to a clamped metal rod using small pieces of candle wax. Heat one end of the rod with a Bunsen burner and observe the pins as the rod heats up. Wear safety goggles, tie back long hair and keep a safe distance from the flame. Do not touch the hot rod or falling pins; let the apparatus cool before handling.



In groups, discuss: What happened to the drawing pins as the metal rod got hotter? Why did this happen?

Attach several drawing pins to a clamped metal rod using small pieces of candle wax. Heat one end of the rod with a Bunsen burner and observe the pins as the rod heats up. Wear safety goggles, tie back long hair and keep a safe distance from the flame. Do not touch the hot rod or falling pins; let the apparatus cool before handling.



How was thermal energy transferred along the metal rod during the experiment?

Attach several drawing pins to a clamped metal rod using small pieces of candle wax. Heat one end of the rod with a Bunsen burner and observe the pins as the rod heats up. Wear safety goggles, tie back long hair and keep a safe distance from the flame. Do not touch the hot rod or falling pins; let the apparatus cool before handling.



In this experiment, did the thermal energy disappear after it left the metal rod? Explain your answer based on the Law of Conservation of Energy.

Attach several drawing pins to a clamped metal rod using small pieces of candle wax. Heat one end of the rod with a Bunsen burner and observe the pins as the rod heats up. Wear safety goggles, tie back long hair and keep a safe distance from the flame. Do not touch the hot rod or falling pins; let the apparatus cool before handling.



List two ways in which your group could improve the experiment.

Paint one metal can black and the other white. Let the paint dry completely. Fill each can with an equal amount of water and place a thermometer in each can. Position both cans under the heat lamp at the same distance where they can receive equal amounts of light.



Measure the initial temperature of the water in each metal can and record in this table. After 20 minutes, measure the temperature in each can again. Record your readings in the table.

|Temperature|Black can|White can|
|---|---|---|
|Initial temperature in °C|___|___|
|Final temperature after 20 minutes in °C|___|___|

Paint one metal can black and the other white. Let the paint dry completely. Fill each can with an equal amount of water and place a thermometer in each can. Position both cans under the heat lamp at the same distance where they can receive equal amounts of light.



When you do this experiment, what precautions should you take?

Paint one metal can black and the other white. Let the paint dry completely. Fill each can with an equal amount of water and place a thermometer in each can. Position both cans under the heat lamp at the same distance where they can receive equal amounts of light.



In groups, discuss these questions. What is radiation?

Paint one metal can black and the other white. Let the paint dry completely. Fill each can with an equal amount of water and place a thermometer in each can. Position both cans under the heat lamp at the same distance where they can receive equal amounts of light.



Why does heat transfer by radiation not require a medium?

Paint one metal can black and the other white. Let the paint dry completely. Fill each can with an equal amount of water and place a thermometer in each can. Position both cans under the heat lamp at the same distance where they can receive equal amounts of light.



Which can, the black or white one, could absorb more thermal energy from radiation? Why do you think this happened?

Paint one metal can black and the other white. Let the paint dry completely. Fill each can with an equal amount of water and place a thermometer in each can. Position both cans under the heat lamp at the same distance where they can receive equal amounts of light.



How do colour and surface texture affect the rate of absorption and emission of thermal energy from radiation?

Paint one metal can black and the other white. Let the paint dry completely. Fill each can with an equal amount of water and place a thermometer in each can. Position both cans under the heat lamp at the same distance where they can receive equal amounts of light.



Suggest two everyday applications where the colours of objects are important for heat transfer.

Place a smaller clay pot inside a larger clay pot. Fill the space between the pots with sand. Pour water into the sand until it is moist. Place a thermometer inside the smaller pot. Cover the whole set-up with a damp cloth.



Record the temperature inside the smaller pot every 20 minutes for an hour.

|Time in min|Temperature in °C|
|---|---|
|0|___|
|20|___|
|40|___|
|60|___|

Place a smaller clay pot inside a larger clay pot. Fill the space between the pots with sand. Pour water into the sand until it is moist. Place a thermometer inside the smaller pot. Cover the whole set-up with a damp cloth.



In groups, discuss these questions. Why is clay a suitable material for the pots?