Lesson Plan

Note: Prior to the first snowfall, ask students to bring in empty 12-ounce orange juice concentrate containers.

Six to eight will be needed each time the class conducts this investigation.

Copy a class set of the Thinksheet, Data Sheet, and Family Page. (See Ready to Print.)
Make an overhead transparency of the Thinksheet, Data Sheet, and Physical vs. Chemical Change (optional) pages for use during the lesson.
Gather
- two similar sized objects of differing densities to help illustrate the concept of density. Some possibilities include:
  - a drinking glass and a plastic cup
  - a bowling ball and a four square ball (future photo)
- six to eight 12-ounce orange juice concentrate containers for each class conducting the investigation
- a scale that measures between 0 and 500 grams
- a base ten block
- one calculator per team
Review Related Resources.
Choose an undisturbed patch of snow for sampling. (future photo)
Try out the Thinksheet Procedure to see what's involved.

Restate the question: "How dense is the snow today?"
Distribute the Thinksheet. Model note-taking on an overhead transparency of the Thinksheet while students take notes in the "Think It Through" section.
- Introduce the term density. (See Background Information.)
  - Density is "how tightly packed matter is."
  - Share one or more examples of objects that are similar in size but have different densities. (See above.)
- Display a units block from a set of base ten blocks. Explain the following:
  - This block is 1 cm long by 1 cm tall by 1 cm wide (1 cm3).
  - The mass of the water that will fill this space is 1 gram.
  - The volume of the water that will fill this space is 1 milliliter.
- Discuss the formula for density (density = mass / volume) and calculate the density of water using the information from the centimeter cube (i.e., 1 gram divided by 1 ml = 1 g/ml density).
- Point out that water is the unit on which density is based.
Group students in teams of four and have each team "number off" from one to four.
Direct teams to read the Thinksheet Procedure and clarify responsibilities.
Direct the "number 1" student in each group to measure the mass of the empty juice container.

Explain to students that snow has a density between 0.1 g/ml and 0.9 g/ml, with "good" packing snow being around 0.4 g/ml to 0.6 g/ml.
Direct one team at a time to make snowballs and throw them into an open area.
Note: Set expectations clearly beforehand to prevent management issues!
Direct students to make a hypothesis for the density of the snow based on their snowball observations.
Model how the "number 2" student in each group should collect their snow sample using the container.
Return indoors after all "number 2" students have collected their snow samples.

Direct teams to complete the remaining steps of the Thinksheet Procedure as you facilitate.
Note: The snow will begin to melt and settle in the container as students work. This will not affect the experiment.
Direct teams to share their density result with you before recording it on the overhead transparency Data Sheet. Verify that the final result is between 0.1 and 0.9 g/ml.
Point out that the melting snow is an example of phase change. (See Background Information.)
Discuss the team results using the overhead transparency Data Sheet.
Have students complete their Data Sheets.
Calculate statistics information at the bottom of the Data Sheet overhead transparency and discuss.

Summarize the Main Points
- Density is how tightly packed matter is.
- Water has a density of 1 g/ml because water is the unit on which density is based.
- Any matter that is more tightly packed than water will have a density greater than 1 g/ml.
- Any matter that is less tightly packed than water will have a density less than 1 g/ml.
- Snow density will vary depending upon how much moisture is in the snow.
- According to our Data Sheet, the average density of the snow today is about ______ g/ml.
- Snow melting from solid to liquid is an example of phase change. Optional: Discuss whether snow melting is a physical or chemical change using an overhead transparency of Physical vs. Chemical Change.
Compliment students for appropriate behaviors during the lesson.
Distribute the Family Page.
Evaluation

Formative: anecdotal notes for each team, incidental questioning of students' rationale for what they are doing, observation of teamwork
Summative: Choose one or more of the following:
- Proficiency Assessment
- Team Evaluation

Take It Further!

Check out Related Resources.
Connect snowfall and the water cycle using free downloadable software. (See Related Resources.)
Explore the relationship between melting snow and watersheds. (See Related Resources.)
Discuss the characteristics of snow with the class. (See Background Information.)
Investigate how salting roads to melt snow can affect the environment and what cities are doing about it. (See Related Resources.)
Repeat this investigation as the snow begins to melt to show that snow density increases with melting.
Repeat this investigation with additional snowfalls to show that snow density varies with each snowfall.