How do you separate a mixture?

1. Focus Question:
How do you separate mixtures?
Investigation 1-1
Mixtures & Solutions

2. 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

3. 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

4. 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

5. 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?

6. 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

7. 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?

8. 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.

9. 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

10. 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

11. 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”

12. 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?

13. 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?

14. 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

15. 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

16. 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

17. • 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

18. 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?

19. 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?