Specific Heat Virtual Labs

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Objective

Students will be able to calculate the amount of Calories per gram of different foods and determine the specific heat capacity of various substances through performing two virtual labs.

Big Idea

Calorimetry experiments allow scientists to determine the Calories per gram of various foods and determine the specific heat capacities of substances.

Introduction

In this lesson students use their knowledge about specific heat capacity and the equation of q=mct to perform two different computer activities.

  • This lesson aligns with the Next Generation Performance Expectation of  HS-PS 3-1 Create a computation model to calculate the change in the energy of one component in a system when the change in energy of the other component(s) and energy flows in and out of the system are known.  It does so because students utilize the equation q=mct to calculate the amount of Calories per gram of various foods and determine the specific heat for various substances.
  • This lesson aligns with the Next Generation Crosscutting Concept 5: Energy and matter.  It does so because students are utilizing the concept of specific heat and how energy is transferred within systems.
  • This lesson aligns with the NGSS Science and Engineering Practice 6: Constructing Explanations: It does so because students are expected to explain their observations in the virtual labs.
  • This lesson also aligns with NGSS Science and Engineering Practice 3: Planning and Carrying out Investigations: It does so because students are performing two virtual labs.  Although they are not physically doing the labs, they are able to see how the lab activities work so I feel that it covers this practice.

For this lesson students need access to computers or tablets to perform the activities.

Explain

5 minutes

To begin this lesson I explain the two virtual labs and go over my expectations for student behavior during the activities. For more details about how I use computers in chemistry see my reflection in the Elaborate section of my Introduction to Energy Lesson.

  • I begin by passing out the two computer labs to students (Calorimetry Virtual Lab and Energy Heat Capacity Computer Lab).
  • I go over a couple particulars for each lab:
    • For the calorimetry lab I tell students to make sure that they are reading each step and that they will not be able to go to the next step until they record in the lab notebook on the computer and press the flashing arrow.
    • For the Heat Capacity lab I tell students to pay attention to the equation because they are solving for "c" not "q".
    • I also tell them that if they are confused to try to figure out the next step with their groups and that if they are still stuck that they should ask me for clarification right away because they need to make sure to stay on task; otherwise, they will not have enough time to complete the lab.
  • I then go over how they will be using the computers with their groups so they should make sure that they are all participating by taking turns on the computer, waiting for all of their classmates to see the visuals, and to make sure that they all record data on their own papers.
  • I reiterate that each student is in charge of their own work and that they should be writing answers in their own words.
  • I then have students go up to their stations with their table groups to work on the labs.

Elaborate Part I

60 minutes

The first virtual lab that students do in this lesson can be found on Glencoe's website. This screencast movie shows how students perform the virtual lab by clicking through the procedures, recording, and analyzing their data.

  • Students perform the lab on the computer and record data and answer questions on their calorimetry virtual lab paper.
  • In this lab students have a chance to calculate the Calories per gram of various food items. 
  • The lab is nice because it first has students predict the Calories per gram of 5 different foods and then they go through doing the experiment and calculations to determine the Calories per gram of those 5 foods. 
  • The lab is also nice because it has students fill in some of the data but does the calculations for them.
  • Finally at the end of the lab I have students reflect on what they found through several analysis questions.
  • Here are two examples of students' completed labs (Student example 1 and Student example 2)
  • The biggest issue I have with this lab is students getting confused with the calculations.  Even though the computer does the calculations for students they have to type in the change in water temperature, change in mass and then Calories into the computer.  Many groups get confused about where to type this data in.  Therefore, while students are working I have to make sure to continuously walk around and make sure that I help clarify for students where to type in data and go through an example with each group.  

Elaborate Part II

30 minutes

For the second activity students perform another set of experiments on the computer, this time using a simulation from the State University of New York's website.  This screencast movie explains the virtual lab.

  • Students perform the activity on the computer where they heat up different substances and then record data on their Heat capacity computer lab paper
  • I like this activity because it is very quick and simple but allows students to see how much energy is put into the system, how much the temperature changes, and the mass of the substance.
  • Students can then take the data that they record and get an accurate value for the specific heat capacity of the substance which they tested.
  • Finally I have student write an explanation (including claim and evidence) as to the relationship between temperature change and heat capacity.
  • Here is an example of one student's completed paper( Specific heat computer student example).  Notice how this student shows their work to calculate the heat capacity and does a good job explaining the relationship between temperature change and specific heat capacity.  The student does not use the term inverse relationship, but has not yet learned this in my class.
  • The biggest confusions that students had with this lab is making sure to calculate for "c",the specific heat, not "q", not q, the heat transferred, and answering the final question.
    • As students worked with their groups I had to make sure to walk around and help them with an example of solving for "c" as that most groups just wanted to multiply their numbers together which would give a value of "q". 
    • Also, some students had a hard time determining the relationship between temperature change and heat capacity.  This biggest issue with this is that students can choose how long to heat the substance for (therefore changing "q") and which mass to use (so changing "m").  If students changed these between substances then it was more difficult to see the relationship between change in temperature and heat capacity.