Specific Heat – Land Versus Water r1.04

Specific Heat – Land Versus Water r1.04

Each page of this lab that contains the symbol should be inserted into your journal. After completing a lab page with the snapshot symbol, tap (in the upper right hand corner) to insert the page into your journal. Note: You may want to take a snapshot of the first page of this lab as a cover page for your journal. The Snapshot button is used to capture the screen. The Journal is where snapshots are stored and viewed. The Share button is used to export or print your journal to turn in your work. Introduction Journals and Snapshots Specific Heat – Land Versus Water

Lab Challenge Imagine standing near a large warm lake at night. If you stand 500m from the lake the night-time air feels cool. As you approach the lake the air starts to feel warmer. Dipping your feet in the lake you find the water is much warmer than the night-time air. What's going on? What does the specific heat of water versus land have to do with the differential heating and cooling of water and sand? How different are water and sand in their rates of heating and cooling? Specific Heat – Land Versus Water

Background How quickly a substance heats up or cools down compared to other substances in its environment is determined by its specific heat. Specific heat is an intrinsic property of a substance and is dependent on molecular structure and phase. Substances that have strong intermolecular attractions have higher specific heats and require more energy to raise or lower the temperature of the substance. Liquid water has strong intermolecular attractions (hydrogen bonding) giving it a high specific heat. The hydrogen bonds can absorb a lot of energy before they break. Specific Heat – Land Versus Water

Self-Check 1.How quickly a substance heats up or cools down is called ________________. a)temperature phase b)bond energy c)absorbent content d)specific heat e)chill factor Specific Heat – Land Versus Water

...Background Specific heat is the amount of energy needed to raise the temperature of 1 gram of a substance 1 Kelvin, and it is expressed in units of joules per gram Kelvin (J/gK). Often, specific heat is expressed using the Celsius scale (J/g°C). The specific heat of water, J/g°C, is often represented as a separate measure, the calorie. Liquid water's specific heat is one of the highest of any substance. Liquid water requires more heat energy to increase in temperature than almost any other substance. Liquid water also can lose more energy than most other substances before it drops in temperature. Specific Heat – Land Versus Water

Self-Check 2.The specific heat of water is also known as a(n) ____________. a)calorie b)heat unit c)joule d)energy budget e)g/mL Specific Heat – Land Versus Water

Safety Follow all standard laboratory safety procedures. Wear safety glasses or goggles. Keep water away from sensitive electronic equipment. Use care when handling hot objects and keep electrical wires away from the hot plate. Specific Heat – Land Versus Water

Materials and Equipment Collect all of these materials before beginning the lab. Note: Part 1 and Part 2 of this lab can be done on two separate days. Part 1 Materials: Stainless Steel Temperature sensors (2) Beakers, glass (2), 250-mL Heat lamp or 150 W incandescent lamp Water, 200-mL Sand, (200 g) Part 2 Materials: Scale or Mass Balance (1 per class) Water, 400-mL Beaker, glass, 500-mL Small tripod, base, and rod, and utility clamp Hot plate Test tube, glass, 18 x 250-mm (large) Disposable insulated cup (2) and lid Tongs Stirring rod Safety glasses or goggles Specific Heat – Land Versus Water

The steps to the left are part of the procedure for Part 1 of this lab activity. They are not in the right order. Determine the correct sequence of the steps, then take a snapshot of this page. Sequencing Challenge – Part 1 A. Weigh out 200g of sand and 200g of water in separate beakers. B. Determine the rate of heating and cooling for sand and water. C. Determine the total change in temperature (∆ °C) for the water and sand. D. Collect data on a graph showing initial, maximum, and minimum temperatures for the water and sand. E. Heat the beakers for 15 minutes using a bright light. Then let them cool for 15 minutes. Specific Heat – Land Versus Water

Sequencing Challenge – Part 2 A. Calculate the specific heat of the sand, and compare it to the specific heat of water. B. Pour the heated sand into the calorimeter. Record temperature data until the mixture cools to room temperature. C. Make a calorimeter out of two insulated cups, 70 g of room temperature water, and the second temperature probe. D. Fill a test tube with sand and insert a temperature probe in the sand. E. Heat the test tube of sand by placing it in boiling water. Record temperatures for five minutes. Specific Heat – Land Versus Water The steps to the left are part of the procedure for Part 2 of this lab activity. They are not in the right order. Determine the correct sequence of the steps, then take a snapshot of this page.

Procedure-Part 1 Heating/Cooling of Water and Sand 1.Connect two temperature sensors to your SPARK Science Learning System. 2.Note: The 1 st sensor you plug in will appear in graphs as “Temperature 1.” The 2 nd sensor you plug in will appear in graphs as “Temperature 2.” Make sure to keep track of which is which. 3.Measure 200g of sand in one beaker and 200g of water in another beaker. 4.Place the 1st temperature sensor (Temperature 1 ) into the water. 5.Place the 2nd temperature sensor (Temperature 2 ) into the sand. Place the tip of the temperature sensor no more than 5 cm below the surface of the sand. 6.Place the heat lamp in a position so it will heat both beakers equally. Specific Heat – Land Versus Water

Procedure-Part 1 Heating/Cooling of Water and Sand Q1: Which substance do you predict will heat up faster -- the water or the sand? Explain your prediction. Specific Heat – Land Versus Water

Procedure-Part 1 Heating/Cooling of Water and Sand Q2:Why is it important to heat both beakers equally? Specific Heat – Land Versus Water

Procedure-Part 1 Heating/Cooling of Water and Sand 7. Start collecting data. After 30 seconds, turn the heat lamp on. Keep recording data! Note: Tap and then tap to scale your graph as needed. 8. View the graphs on the next page. The top graph shows the 1 st temperature sensor you plugged in (Temperature 1 ). The bottom graph shows the 2 nd temperature sensor you plugged in (Temperature 2 ). 9. Turn the heat lamp off after 15 minutes. Keep recording data as the sand and water begin to cool. 10.Collect data for 15 more minutes, then stop collecting data. Specific Heat – Land Versus Water

Analyze the Graphs 11. Select the region of heating for water.* 12. Use the button to find the rate of heating for water (slope of the line).* 13. Use the button to label the slope value onto the graph above the section of line you highlighted. 14.Select the region of cooling for water, and repeat steps 12 and 13. (You can deselect the previous one now.) 15.Repeat the above procedure for finding the rate of heating and cooling for the sand. 16.When all four parts of the graphs are labeled, take a snapshot and save your work. * To Find the Slope for a Portion of a Run of Data: 1.Tap to open the tools palette. 2.Tap and then tap two points on the data run. 3.Adjust using both buttons and then tap. 4.Tap and select linear fit then tap OK (m=slope). To Label the Slope on the Graph: 1. Remember the m value, and tap. 2. Type the value of m and press OK. 3. Take a snapshot of the graph now. Specific Heat – Land Versus Water

Analysis 1. What linear fit data represents the Rate of Cooling or the Rate of Heating? Specific Heat – Land Versus Water

2. Calculate a ratio for the Rate of Heating (sand) compared to the Rate of Heating (water). 3. Calculate a ratio for the Rate of Cooling (sand) compared to the Rate of Cooling (water). Analysis Specific Heat – Land Versus Water

Analysis 4. Consider the ratios of the rates of heating and cooling for sand to water. What do these ratios tell you about the possible specific heat of sand compared to the specific heat of water? Specific Heat – Land Versus Water

Analysis 5. In this exploration, what was the independent variable, what was the dependent variable, and what factors did you hold constant? Specific Heat – Land Versus Water

Procedure-Part 2 Specific Heat of Sand 1.Fill the 500-mL beaker about ¾ full with water. 2. Place the beaker on the hot plate, and turn it on to the highest setting. 3.Set up the tripod, base, and rod while you wait for the water to boil. Fasten a utility clamp just above the beaker. 4.Find and record the mass of an empty test tube. Fill the test tube halfway with sand and mass it again. The difference is the mass of the sand. Record the mass in the text box to the right. You will need this data on pg. 29. Specific Heat – Land Versus Water

Q3: Why is it important to determine the mass of the sand without the test tube? (Hint: the relationship for heat exchange in matter is Q = mc ∆T, where Q is the total amount of energy exchanged, m is mass, c is the specific heat, and ∆T is the change in temperature.) Procedure-Part 2 Specific Heat of Sand Specific Heat – Land Versus Water

Procedure-Part 2 Specific Heat of Sand 5. Insert Temperature Probe 1 into the middle of the sand in the middle of the test tube. 6.Clamp the test tube in the 500-mL beaker of boiling water. Make sure the sand in the test tube is below the water level. Q4: Why is it important to keep the end of the temperature probe away from the bottom or sides of the test tube? Specific Heat – Land Versus Water

Collect Data 1.On the next page, tap to start collecting data with Temperature Probe 1 in the sand in the test tube. 2.To view only the current run of data, open the data run box and deselect the previous run. 3.After 5 minutes, tap to stop collecting data. 4.Resize the graph to show the entire data run. 5.Find the minimum and maximum temperatures of the sand: open the Tools Palette and tap and then, and select Minimum and Maximum and OK. Record these values where indicated on the next page. Specific Heat – Land Versus Water

6. Record the minimum and maximum temperatures below and save this page to your journal. You will need this data on pg. 29. Collect Data Specific Heat – Land Versus Water

7. Make a calorimeter by nesting two disposable insulated cups. 8. Fill the nested cup with 70 g of room-temperature water. (Measure this precisely; don’t lose any.) 9.Insert Temperature Probe 2 into the calorimeter. You can insert the probe through a small hole in the cup’s lid, along with a stirring tool. 10.Tap to find the initial temperature of this room- temperature water. (graph on next page) 11.Lift the lid. Using tongs, grasp the heated test tube and dump the heated sand into the insulated cup. Replace the lid with the probe and continue recording data. Procedure-Part 2 Specific Heat of Sand Q5: What is the purpose of nesting one cup inside another? Specific Heat – Land Versus Water

Collect Data 1.Gently stir the sandy water, recording the temperature until a maximum temperature has been reached, and the temperature has decreased for a minute or more. 2. Tap to stop collecting data. 3. Record the minimum and maximum temperature of the water in the table on the next page. Specific Heat – Land Versus Water

Analysis 1. Below, record the mass of the water from pg. 27, and the change in water temperature from data on pg Below, record the mass of the sand from pg. 22, and find and record the change in temperature of the sand from pg Use Q = mc  T to find the energy change (Q) of the water. Show your work. Specific Heat – Land Versus Water

Analysis 4. Knowing the energy change (Q w )of the water, what can you use as the energy change (Q s ) of the sand? Why? Specific Heat – Land Versus Water

Analysis 5. Use your previous data and c sand = Q sand /(m sand  T sand ) to find the specific heat of the sand. Specific Heat – Land Versus Water

Synthesis 1. Assume that the data you got for sand represents data for land in general. How does the specific heat of sand compared to the specific heat of water relate to the differential heating and cooling of land versus water? Specific Heat – Land Versus Water

Synthesis 2. Explain how the proximity to a large body of water influences weather. Provide an example. Specific Heat – Land Versus Water

Multiple Choice 1.If water has a high specific heat, which of the following would be true? a)Water cools down rapidly. b)Water retains heat for a long time. c)Air over land located near water is warmer during the night than inland locations. d)It takes a lot of energy to heat water. e)All of the above are true EXCEPT (a). Specific Heat – Land Versus Water

Multiple Choice 2.Compared to a substance with a low specific heat, a substan c e that has a high specific heat __________. a)requires more heat per gram to be added to it to cause an increase in temperature b)requires less heat per gram to be added to it to cause an increase in temperature c)requires the same amount of heat per gram to be added to it to cause an increase in temperature d)has a larger mass e)None of these is true. Specific Heat – Land Versus Water

Multiple Choice 3.Water has a high specific heat because __________. a)it changes from a solid to a liquid phase at a relatively high temperature b)it has strong chemical bonds, particularly hydrogen bonds, between molecules c)it boils at 100 °C d)it freezes at 0 °C e)It can get very hot Specific Heat – Land Versus Water

Multiple Choice 4.The high specific heat of water compared to that of land results in __________. a)the small range of temperatures in the oceans compared to that on land b)coastal climates that have smaller ranges of temperature compared to those of inland areas c)the ability of large fresh water bodies to stay in liquid phase when air temperatures drop below 0 °C d)All of these are true. Specific Heat – Land Versus Water

You have completed the lab. Congratulations! Please remember to follow your teacher's instructions for cleaning-up and submitting your lab. Specific Heat – Land Versus Water

ALL IMAGES WERE TAKEN FROM PASCO DOCUMENTATION, PUBLIC DOMAIN CLIP ART, OR WIKIMEDIA FOUNDATION COMMONS: References Specific Heat – Land Versus Water