Focus Question:How do you separate mixtures?

Investigation 1-1Mixtures & Solutions

Safety First!• Investigate the properties of solid and

liquid materials.• Use a variety of tools and techniques.• Never taste any material unless you have

been given permission by the teacher to do so.

• Wear safety goggles when working with hazardous materials.

• Student roles

Matter• The stuff the world is made of– You, your desk, the oceans, and the air

• Exists in 3 different forms– Solid, Liquid, Gas

• Has mass & occupies space• Investigate properties of matter• Today’s matter:– Gravel– Powder - diatomaceous earth– Salt - sodium chloride

Preparation• Use sticky notes to label 3 cups– G - gravel– P - powder– S - salt

• Chemical manager brings cups to chemical station• Measure 1 level spoon of each material into the

matching cup– 1 level spoon of gravel in G cup– 1 level spoon of powder in P cup– 1 level spoon of salt in S cup

• Use correct spoon to measure each material• Materials stay at the chemical station

Observations• Observe the materials informally - okay to

look and touch, but not taste• Scientists make careful observation and

detailed records of their investigations.• Record the properties of these 3 materials

in Part 1 of Mixtures sheet• Use hand lenses to help with observations• What do you observe?

Adding Water• What do you think might happen if you add

water to each cup containing the dry materials?

• Procedure:– Use syringe to add 50 ml of water into each

cup– Return syringe & water to bin when done– Stir contents with stick– Observe what happens– Record observation on notebook sheet Part 2

Mixtures!• When you put two or more materials

together, you make a mixture• What is the mixture in each cup?• What are other mixtures you use in your

everyday life?

Separating Mixtures• Mixtures can always be taken apart• How can these 3 mixtures be separated? • Homework: Note ideas for separating

mixtures. • Goal is to separate the mixtures so that

water is in one cup and solid material is in another.

Clean-up• Remove labels from cups• Dispose of leftover solutions• Save gravel on paper towel• Throw away wet paper towels• Rinse cups and replace in bins• Add 3 sticky notes to each bin

How do you separate a mixture? (continued)

• We left off with 3 mixtures– Gravel and water– Powder and water– Salt and water

• Homework was to think about how to separate the mixtures so that the water was in one cup and the material was in another

Set-up• Recreate the 3 cups (G, P, S - 1 scoop of

material in each)• Add 50 ml of water to each cup & stir• Label second set of cups “G”, “P”, & “S”

Screen• Filter might help to separate the mixtures• One type of filter is a screen• Read and follow procedures in Part 3 of notebook

sheet– Select one of the mixtures - G, P, or S– Place screen on top of a second cup with same label– Stir mixture thoroughly– Immediately pour the mixture through the screen– Record results

• Which mixtures were separated by the screen?

Filter Paper• Filter paper - fine-mesh screen with holes so small

they can’t be seen with naked eye• Funnel and Filter paper set-up• Stir Powder and Salt mixtures again• Try to separate using filter paper• Carefully open up filter papers and spread flat on

paper towel• Which mixture was separated by the filter?• How are a screen and a paper filter similar? How

are they different?

Solution• What happened to the salt mixture?• If a solid and a liquid are mixed and..– The solid seems to disappear in the liquid– The mixture can’t be separated with a filter

• It is a special kind of mixture called a solution

• Salt dissolves in water to make a saltwater solution

• Complete Thinking about Mixtures sheet

Clean-up• Remove labels from cups• Dispose of leftover solutions• Save gravel on paper towel• Throw away filter papers and towels• Rinse cups and replace in bins• Add 6 sticky notes to each bin• Get ready for vocabulary

Vocabulary

• Matter - can exist in three forms - solid, liquid, and gas

• Mixture - two or more materials stirred or mixed together

• Property - characteristic of an object, something you can observe such as size, color, shape, or texture

• Solution - a special mixture formed when a material dissolves in water.– Solutions are clear and cannot be separated

with a filter

• Dissolving - a process in which a solid material seems to disappear into a liquid

• Diatomaceous earth - the skeletal remains of aquatic organisms

Content

• What happens when you add water to a cup containing a dry material?

• How can a mixture be separated?• What happens when salt and water are

mixed?• Your questions?

Thinking About Mixtures• What is a mixture? Example?• What is a solution? Example?• Is salt & water a mixture, a solution, or

both? Explain.• How do you know when you’ve formed a

solution?• How can mixtures be separated?• How are screens & paper filters alike?

Different?