Earth MaterialsInvestigation 1

Mock Rocks

Part 3 – Observing Crystals

Science Jobs

Manager – this person will make sure that all members are on task

Reporter – this person will report the results of their groups work, you may need to take notes

Materials getter – this person will get materials

Materials collector – this person will return materials

Investigation 1, Part 1 Review Rocks have many properties, including

shape, size, color, and texture Geologists use rock properties to help identify

different rocks Some dimensions of rocks can be measured

and compared

Investigation 1 – Part 2 Review The difference between rocks and minerals

Rocks are made up of different ingredients, minerals of only one.

How the minerals in a rock can be separated Some minerals can be separated and identified by

breaking the rock apart. Some rock materials separate and settle when

mixed with water. Some minerals dissolve when mixed with water.

Investigation 1 – Part 2 Review A rock is an earth material made up of

different ingredients called minerals. A mineral is an ingredient of rocks that

cannot be broken down any further. We do not mean that it can’t be hit with a hammer and broken into smaller piece. We mean that no matter how many pieces you break it into, it is still the same material.

What We Will Learn

What is left behind when the water evaporates from our dishes.

How to identify the material that is left behind.

Materials

FOSS tray with evaporation dishes 4 hand lenses 4 copies of the Crystal Identification Key –

Student Sheet No. 12

What We Will Do

Material getters – take your materials to your group.

Use your hand lenses to carefully observe what is left in the evaporation dishes.

Draw a detailed picture of what you see. Discuss what you see in your groups. Reporters share your group’s findings. What did your groups find that were alike and

different?

Crystals

The little squares in the dishes are called crystals. A crystal is a solid form of a material that can be identified by its characteristic shape or pattern.

What do you think these crystals might be? Use the Crystal Identification Key to compare

and identify the crystals in the dish.

Discussion

Discuss how the crystals got from the mock rock to the evaporation dish.

Share. When water was added to the mock rock material,

the salt dissolved in the water. When the liquid from the vial was placed in the dish,

the dissolved salt went in with the water. The water evaporated into the air, leaving salt

crystals in the dish.

Earth Materials BookletMock Rocks – Page 6 – 7 Explain what you see in your evaporation

dish and how it got there. Refer to pages 2 – 6 in your booklet to make

a list of the mock rock ingredients on page 7. How is a mock rock like a real rock? Discuss

in your groups and then record your answer.

Vocabulary

Crystal – the solid form of a material that can be identified by its shape or pattern

evaporation – when the liquid water becomes water vapor

What We Have Learned

The mock rocks contained salt. By putting the liquid from the vials in the

evaporation dish and letting the liquid evaporate we can use a crystal identification key to identify the substance that was dissolved in the water.

Science Story

Read “Postcards from the Ledge”