ACTIVITY #9: Heat Energy and Temperature: There is a Difference! The lady who is watering the lawn is surprised by the temperature of the water in the hose that has been lying out in the lawn all day. You may have also experienced this in your own backyard. How is it that the water in the garden hose can heat up so quickly, but the water in your swimming pool doesn’t change much at all? Aren’t they both receiving the same amount of heat energy from the sun?  What does it mean to ‘heat something up’?  Can we measure heat energy? Can we measure temperature?  Can ‘temperature’ be transferred to an object?

GOALS: GOALS: In this lab activity, you will …  Observe that there is a difference between the heat energy transferred to an object and the change in temperature that results from this transfer of energy.  Learn how the mass of a substance influences how much its temperature will change when it receives heat energy. And how they respond differently when they absorb energy. Activity Overview: Activity Overview: A synopsis of this lesson is as follows… Tea candles will be sources of heat energy. The first step in the activity is to make an energy chain describing where the heat energy produced by the candle comes from. Then the class will divide into five groups. Two groups will use candles to ‘heat up’ 100 ml of water, two other groups will ‘heat up’ 200 ml of water, and the fifth group will ‘heat up’ 200 grams of sand. Groups that are working with 100 grams of water will separate and use either 2 or 4 candles to ‘heat up’ their water. The groups working with 200 grams of water will divide up in the same way, and the group working with the sand will use 4 candles. Each group will measure and record how the temperature of their water changes over a 6-minute period. The class will then share their results and look for patterns in the results ---STOP--- MAKE A CHART (Start temp, 6 min intervals)

MAKING SENSE OF ENERGY … Everyone is familiar with candles. When a candle has been lit, it emits light, and heat energy. Like the stored energy in food and gasoline, there is a stored energy in the wax of a candle. This form of stored energy, called chemical energy. Things that burn release heat energy when they burn, and wax is no exception. We have learned that heat energy is the combined kinetic energy of tiny particles. Exhaust gases are produced whenever anything burns, and the heat energy produced by the burning of a candle is the combined kinetic energy of the particles of the exhaust gases. The burning candle also produces energy in the form of waves. Light waves and waves that are like light, but not visible to our eyes are produced by the burning candle. In this activity, we will focus our attention on the heat energy carried by the exhaust gases.

The class will be divided into several groups. Each group will make similar measurements, but will investigate a different system than the other groups. After completing the investigations, the groups will share their results with the class. Starting with the stored energy in the wax of the candle, construct an energy chain describing the flow of energy from the wax to the air. How much heat energy is produced (or needed) is measured in units called a Joule. ( Calories, or even BTU’s (British Thermal Units) Just for this activity, we are going make up our own unit of energy. We will be using candles as sources of heat energy. Every minute a candle burns, a certain amount of wax burns, and a certain amount of heat energy is produced. We are going to call the amount of heat energy produced by a single candle in one minute a Moche (pronounced mooche). 1 Moche = 1 Minute Of Candle Heat Energy Every minute that a candle burns, it creates one (1) Moche of heat energy. If a candle is placed under a container of water for 5 minutes, it delivers 5 Moches of heat energy to the container and water. In this activity we will need to express how much heat energy we deliver to pans of water and sand. We will express our heat energy in Moches.

1. Each group will need to gather 2 aluminum pans, 2 – 4 candles, 2 -4 wooden blocks, 4 clothespins, and a timer. Some groups will need access to a large source of room temperature water and other groups will need access to 200 grams of sand. Question #1: Will the 200 grams of sand have the same volume as the 200 ml of water? Why? 2. Take one aluminum pan and place a clothespin on each corner and invert it. This will serve as a stand for the pan holding the water. Carefully follow your teacher’s instructions because each group will be doing a different test. We will combine the results of each group’s investigation in the end. Don’t start yet!!

Organizing the Four Samples The plan is to use different numbers of candles to heat different quantities of water and sand in the pans. Two candles will be placed under one 100 mL pan and two placed under the 200 ml pan. Four candles will be placed under the other 100 mL pan and four candles under the 200 ml pan. Once the candles are lit, and placed under the support pans, the temperature will be measured and recorded every minute for 6 minutes. We will express these quantities of heat energy in Moches IF 1 candle burning for 1 minute produces 1 Moche of heat energy, Then 1 candle burning for 6 minutes produces 6 Moches of heat energy. And 2 candles burning for 6 minutes produces 12 Moches of heat energy. And 4 candles burning for 6 minutes produces 24 Moches of heat energy. Pull your hair up!!!!!

The graph used is label look like this: 100 g of water 200 g of water/sand 2 candles 2 candles 4 candles 4 candles 12 Moches 12 Moches 24 Moches 24 Moches Question #2: Which samples will receive the most heat energy? Explain Question#3: Which samples will receive the least heat energy? Explain Prediction #1: Which pan of water will have its temperature increased the most? Prediction #2: Which sample will experience the smallest temperature change? Prediction #3: Will any two samples experience approximately the same temperature change?

1. 2. After the cards are prepared, separate the 5 test pans, and prepare to begin by placing the designated number of candles on wooden blocks, arranging them in a line so that the candles are close enough to touch. Light the candles, giving them a few minutes to burn. When you see a small puddle of wax developing at the bottom of the wick, the candle is ready to use. Carefully slide the support pan over the candles, and place the test pan of water on top. Be sure to start the stopwatch as soon as the pan of water is placed above the candles. Place the digital thermometer so the probe is submerged in the water sample or buried in the sand. Record the temperature once every minute for a total time interval of six (6) minutes. After you have collected all of your data, calculate how much the temperature of the water increased in each of the five samples. Write this number on the corresponding index card. Compare the results of the experiment to your predictions. This can be accomplished by creating a chart and a graphs

Question #4: In this experiment, what determines the amount of heat energy transferred to the samples? Question #5: In this experiment, what determines the size of the temperature increase in the water samples? Question #6: Does the 200gr of sand that received 24 Moches of heat energy respond the same as the 200 ml of water that also received 24 Moches of heat energy? If the sand responded differently than the water did, explain how the response was different. Question #7: What do you think people mean when they say ‘heat up’ in sentences like: “It’s heating up outside.” “Let’s heat up the pizza in the oven” “Heat up the water with two candles.”

Investigating Further … Going for a swim? … in the middle of winter? Each year, during the first weekend in February, numerous people from Delaware and the surrounding states make their way to the frigid waters of the Atlantic Ocean at Rehoboth Beach, Delaware. They are there for the annual Lewes Polar Bear Plunge, which is a charity event held to raise money for Special Olympics Delaware. Isn’t the water nearly freezing? The ocean water temperature does not fluctuate nearly as much as the air temperature or as much as the temperature of the beach sand, so it isn’t as cold as you would guess. The huge mass of the ocean water keeps the temperature from fluctuating drastically during the year. So what does one have to do to participate? It’s easy … gather sponsors, pick out a warm swimsuit, and then prepare for your plunge into the ocean water during the winter!