# How does water compare with sand?

## 2. Share the data

**Note:** The full class data set can reveal patterns about the weight-volume relationship of water and sand, but it can also present students with more information than they are ready to process. Using different colors to highlight the water data column and the sand data column will help students focus on just those columns. Before starting to discuss this data, hide the Sand Volume data, and focus on just the water data.

Remind students that they have already collected lots of data about water and sand as they made their mini-lakes. They continue to think about how sand and water compare as they analyze this collection of data.

If they have not already done so, students should record in the table their team initials and the volumes of water and sand they used in their mini-lake. Student data is found on [Making mini-lakes] page in the Science Notebook.

#### Weight and Volume of Water and Sand

Team | Weight | Water Volume | Sand Volume |
---|---|---|---|

Team 1 | 150g | 150cc | 94cc |

Team 2 | 150g | 149cc | 94cc |

Team 3 | 150g | 150cc | 92cc |

Team 4 | 140g | 141cc | 87cc |

Team 5 | 140g | 140cc | 88cc |

Team 6 | 140g | 140cc | 87cc |

Team 7 | 130g | 128cc | 82cc |

Team 8 | 130g | 130cc | 81cc |

Team 9 | 130g | 130cc | 81cc |

Team10 | 120g | 120cc | 75cc |

Team 11 | 120g | 120cc | 76cc |

Team 12 | 120g | 122cc | 75cc |

### Review the water data

Highlight rows in which the Weight and Water Volume *are the same*. If no team has the exact same value for the weight and volume of water, highlight the rows in which the values are closest. Ask students to focus on just those rows.

What can you say about the weight and volume data in the highlighted rows?

- The weight of the water and the volume of the water are the same number (or almost the same number).

We see that (150g) of water take up (150cc) of space, and (120g) of water take up (120cc) of space. How much space do you think 50g of water will take up? (Or 1 g of water?)

- 50cc (1cc)

What do you notice about the rows that are not highlighted?

- The weight and volume are not exactly the same number, but they are very close.

Explain that making exact weight measurements is not always possible with our scales since these only measure to the nearest gram, so not all water data has the same number for weight and volume. The ones that are not the same are very close.

**Note:** When scientists created the metric system, they decided that the weight of one cubic centimeter of water would be called a *gram*. Each gram of water takes up exactly one cubic centimeter of space.

### Use a concept cartoon

Give the class a few minutes to write a response to the concept cartoon [Weight and volume data] in the Science Notebook. Explain that the task is to figure out which two students in the concept cartoon investigated a sample of *water* and to explain the reasons they think so. This cartoon reinforces the fact that 1cc of water weighs 1 gram, and that small errors are typically a part of measurement.

### Review the sand data

Return to the class data. Reveal the Sand Volume column. Highlight the volume and the weight of sand in one row.

It may help students understand the organization of the data table if a volunteer reads the information provided in the row you have highlighted.

Example: Team 3 found a weight of 150g of water had a volume of 150cc. Team 3 found a weight of 150g of sand had a volume of 92cc.

- Each 1g of sand takes less than 1cc. 150g of sand take up 92cc of space.

Point out that sand is heavy for its size compared with water.

- water

### Review heavy for size

Point out the containers of water and sand you have distributed. Ask students to take turns holding one in each hand and comparing the weights.

- The volumes are equal.

- The sand is heavier than the water.

Point out that as long as the volumes are equal, sand is a material that is heavy for its size compared with water. For samples of any size - as long as the size of the samples is the same, sand will weigh more than water.

- solid rock (there are no air spaces between the particles), copper, steel

- Yes, if you have a lot of water and a small amount of sand, the water will weigh more.