Consider before watching the videos:

Does a pound of feathers weigh the same amount as a pound of bricks? Does a pound of feathers have the same volume as a pound of oranges?

Lab Experiments (Write protocols based on the videos then complete your protocols as you perform experiments in class):

1. Density of a Regular Object
2. Determining Density of Irregular objects

 

Lab Technique videos (Use these if you need help with your measurements)

1. Weighing
2. Measuring Volume

 

Data analysis and calculations (Use these if you need help with your data and calculations)

1. Measurements
2. Significant figures
3. Solutions
4. Composition of Solution

  The prelab is due before your lab class meets and must include Experimental Protocol, Chemical Table and Equipment Table.

(Analysis) Watch the experiment videos. Take notes on the protocols. Stop the videos and re-watch as necessary to acquire details of the procedure. Write out the protocol for each part of the experiment.  (It can be written in sequential steps.  Complete sentences are not necessary.)  This is the protocol you follow, so be detailed.

Experiment 1: Record the mass and volume of regular objects.

 

Experiment 2: Record the mass and volume of irregular objects.

(Analysis) Identify the equipment (type AND size) needed for the experiment and include the name and an image (picture) of each.  Be sure to describe the equipment, how to use it, and why it is suitable for this use.

Equipment Name	Equipment Picture or Description	Intended Purpose

Acquiring competencies) Following your detailed protocol, perform all the experiments. Record your observations and take pictures of your key steps in the process. Your observations and images need to be incorporated in your data section and this section should be as detailed as possible as you will use this information to complete your discussion.   Record both the mass and the volume measurements for every object you investigate 3 times.

Part 1: Find the mass of your regular objects. (Add more lines as needed)

Object name	Mass 1	Mass 2	Mass 3	Average

 

Part 2: Find the volume of your regular objects. (Add more lines as needed)

Object name	Length	Width	Height	Volume
	Average:	Average:	Average:	Average:
	Average:	Average:	Average:	Average:

 

Part 3: Find the mass of your irregular objects. (Add more lines as needed)

Object name	Mass 1	Mass 2	Mass 3	Average

 

Part 4: Find the volume of your irregular objects. (Add more lines as needed)

Object name	Initial Volume	Final Volume	Difference
	Average:	Average:	Average:
	Average:	Average:	Average:

1. (Interpretation) Select one of your mass or volume measurements and identify the value, uncertainty and unit in the presented quantitative observation.
2. (Manipulation) Show how you calculated the volume of your second regular object. Include units and consider the number of significant figures in your calculation.
3. (Manipulation) Show how you calculated the density of your second regular object. Include units and consider the number of significant figures in your calculation.
4. (Representation) Fill in the table with your calculated values for your regular objects:

Object name	Material	Average Mass	Average Volume	Density	Known value

 

5. (Representation) Fill in the table with your calculated values for your irregular objects:

Object description	Mass	Volume	Density

 

6. (Analysis) Comment on the precision of your mass measurements using your data as evidence.
7. (Analysis) Comment on the precision of your volume measurements using your data as evidence.
8. (Analysis) Comment on the accuracy of your density measurements using your data as evidence.
9. (Manipulation) Calculate the % error in the density calculations using the following formula:                                                         % error=((experimental value-known value))/(known value)×100%

Make this number positive (take the absolute value).

10. (Manipulation) Show how you calculated the average of your 3 mass measurements for experiment 1. Include units and consider the number of significant figures in your calculation.
11. (Manipulation) Show how you calculated the displacement volume for your irregular objects using your data for your first measurement of experiment 2. Include units and consider the number of significant figures in your calculation.
12. (Analysis) Classify mass as an extensive or intensive property and provide a supported argument for your choice.
13. (Analysis) Classify volume as an extensive or intensive property and provide a supported argument for your choice.
14. (Analysis) Classify density as an extensive or intensive property and provide a supported argument for your choice.
15. (Existing knowledge, research and views) List the elements making up the brass alloy with their known density values.
16. (Manipulation) Estimate the composition of your alloy using the density you measured during the experiment. Present the stepwise calculations with the appropriate units included.
17. (Existing knowledge, research and views) List the approximate % mass composition for the brass object.
18. (Analysis) Compare the estimated % mass composition of your brass object to the known alloy compositions and identify the type of brass your object is likely made of.
19. (Analysis) Identify at least one of the 12 principles of green chemistry applied in this experiment. Justify your selection. 12 Principles of Green Chemistry
20. (Assumptions and analysis) Fill in the following table using the observations and data from your experiments.

Assumptions made	Testing the assumption	If assumptions are wrong ...
The distilled water is pure	Evaporate it and check for residue	The density would change depending on the density of the contaminant
The objects used for displacement do not absorb water	Take the mass before placing in water and again after it was removed form water and dried
Mass shown on the scale is accurate		Different scales show different mass for the same object

  The summary has two parts: an abstract and an experimental protocol reflecting the experiment that you actually performed. The abstract and experimental protocol should both be between 100-250 words, size 12 Arial font each. There may be multiple experimental protocols for one experiment.

Part 1.

Title of Experiment: Performed tasks and applied techniques to accomplish the goal of the experiment and a description of the system under study (the title you are given for the lab is insufficient). Ex. Calibration of Mass and Volume Measurement Techniques to Determine the Density of Irregular Objects and Estimate the Mass Composition of Alloys

(This is a highlight of what you learned from performing the experiment and processing your collected data. Below is a template and an example of what you are expected to write.) In this lab experiment we investigated [purpose of your experiment] using [list the materials you worked with] and we found that [present the highlights of your results (include numbers)]. The results [present significant results]. The collected data compares to [draw conclusion about your results compared to other sources (this could be another group or the literature value)]. The [add type of measurement individually] measurement was collected using [describe instrument by sensitivity].   Think through this before writing:

1. Purpose: What were you trying to do?
2. Materials used: What chemicals and materials did you work with?
3. Method: What instruments were used to collect measurements and how were the measurements collected?
4. Results: What did you find out about the objects under study?
5. Significance: What did you learn about the precision and accuracy of your techniques? How do your determined values compare to reported values?

  Ex. In this lab experiment we investigated the determination of density from volume and mass measurements using regular objects made of Fe, Zn, Cu, Ni and Al, and found that our experimental densities had errors of less than …% for the individual elemental cubes. The density of the [identify the irregular object] that is composed of [list the components] was determined to be …. g/mL and we estimated the composition of the alloy to be …% X and …% Y by mass. Our estimate for the mass composition compares [favorably/unfavorably] with the literature value of …… All mass measurements were collected on digital scales with 0.01 g sensitivity. The edge-length or the regular objects was measured using a ruler with a 0.01 cm sensitivity and the volume of the irregular objects was determined using a … mL graduated cylinder via volume displacement.  

Part 2.

Title of Protocol (Brief description of the experiment in bold) Ex. Determining the Density of a Cube-shaped Iron Object   Experimental Protocol (This is a condensed and organized description of the protocol you actually completed during class. Use the exact amounts of materials and list the exact equipment that you used in performing the experiment. The length of this section depends on the complexity of your experiment, usually 3-4 sentences maximum in one paragraph.)   Ex. We measured the edge length of a cube-shaped iron object using a ruler with a sensitivity of 0.01 cm and found that the average distance from 3 independent measurements was …… cm. We weighed the iron object a digital scale with a sensitivity of 0.01 g and found that the average mass from 3 independent measurements was …… g. With an average volume of …….. cm³, the density of the iron object is ….. g/ cm³. (For each material and procedure)