Density Inquiry Lab
Overview
This describes a lab that can be used in Middle School (Grades 6 - 8) for helping students to grasp the concept of density.
Introduction
In this lab on density, students are asked to carry out three different exercises involving the concept of density.
Station 1: What is the density of pure water at room temperature?
In this station, students have access to room temperature water, graduated cylinders, plastic pipets, plastic cups, and electronic balances (triple beam balances may also be used). Students determine the mass of a given volume of water (their choice!), and then they determine the density. They then compare their results with their classmates.
Station 2: The Density Cubes
In this station, students have access to 6 density cubes. I got mine from Educational Innovations (www.teachersource.com). The cubes are available from them for $29.95 per set of six. The cubes are made of different metals and are identical in volume, but not in mass. Students are asked to rank the cubes in decreasing (or increasing) order of density. I put circular price tag paper on the cubes and wrote numbers on the paper with a Sharpee to help identify them. Students use a ruler and an electronic balance or triple-beam balance to determine the densities.
Station 3: Thickness Of Aluminum Foil
In this station, students are asked to determine the thickness of a sheet of aluminum foil. Students tear off a sheet from a role of aluminum foil. I advise them to get a sheet that is close to a rectangular or square sheet as possible. They are then asked to use a ruler, calculator, and balance to find the thickness of the foil. I give them the density of aluminum (2.70 g/mL).
Density Inquiry Lab Student Worksheet
The Next Generation Science Standard that can be addressed in this activity is:
MS-PS1-1. Develop models to describe the atomic composition of simple molecules and extended structures.
The density of pure water at room temperature is 1.0 g/mL. You can have students compare their findings with their classmates, take a class average, and determine percent error with this lab.
Encourage students to get a large enough piece of aluminum foil (the size of a sheet of notebook paper works well). If the foil sheet is too small, it will be difficult to get an accurate reading of its mass (depending on how sensitive your balances are).
Some students have tried to fold up their sample of aluminum foil and then calculate length x width x height. Discuss where errors can occur with this method.
Density Inquiry Lab Name:
In this lab, you will be working on three different stations that put the formula for density to work. If you recall, the formula for density is:
Density = Mass / Volume
You may complete these stations in any order. For full credit, describe the procedures you chose to follow to solve the problems, and answer the questions.
Station 1: In this station, you are asked to determine the density of water at room temperature. You have the following materials at your disposal:
* graduated cylinder * plastic cup
* water * plastic pipet
* balance
The density of water at room temperature is: _______________.
Describe the procedures you followed to determine the density of water.
Station 2: In this station, you are asked to determine the density of six metal cubes and to arrange them in order of increasing density. You have the following materials at your disposal:
* 6 metal cubes * ruler
* balance
The metals, in order of increasing density are:
# _____ (density = ________ g/mL)
# _____ (density = ________ g/mL)
# _____ (density = ________ g/mL)
# _____ (density = ________ g/mL)
# _____ (density = ________ g/mL)
# _____ (denisty = ________ g/mL)
Describe the procedures you followed to determine the density ot the six cubes.
Station 3: In this station, you are asked to determine the thickness of a piece of aluminum foil. Remember that the volume of an object is equal to the product of its mass, its length, and its height. The density of aluminum is 2.70 g/mL. Remember that 1 mL = 1 cubic centimeter. You have the follwoing materials at your disposa:
* sheet of aluminum foil * ruler
* balance
What is the thickness of the aluminum foil?
Describe the procedures you followed to determine the thickness of the aluminum foil.
Questions:
1. Does the volume of water you choose to work with in Station 1 matter? Why or why not?
2. Is density an intensive property or an extensive property? How can you tell?
3. What effect does the temperature of water have on its density? What have you experienced that tells you this?