Mixtures and Solutions
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This is a paper science activity. You will read a little, look at a picture and a chart, and answer questions with a pencil. You do not need a computer or any lab supplies. Work by yourself and do your best. If a question is hard, skip it and come back. You may read the words out loud to yourself.
Start Notice & Wonder 5 min
Think about foods and drinks you have seen mixed together.
1Trail mix has peanuts, raisins, and pretzels all tossed together. Write one thing you notice and one thing you wonder about trail mix.
2You stir a spoon of salt into a cup of water and keep stirring. The salt seems to disappear. Where do you think the salt went? Write your best idea.
Build Read the Science 5–10 min
Mixtures and solutions
A mixture is two or more things put together that are not joined into a new material. In many mixtures, like trail mix, you can still see the different parts.
A solution is a special kind of mixture. In a solution one thing dissolves into another and it looks the same all the way through. Salt water is a solution. The salt did not disappear — it broke into tiny bits too small to see, spread out in the water. You can taste it, and you can get it back.
The parts of a mixture keep their own properties, so you can separate them using those properties:
- Sift — shake through a screen to split big pieces from small ones.
- Magnet — pull out a part that is magnetic (like iron).
- Filter — pour through a coffee filter or paper to catch bits that will not fit through, while liquid passes.
- Evaporate — let the water dry into the air. The dissolved solid, like salt, stays behind.
Word Bank
- mixture
- two or more things put together that keep their own properties.
- solution
- a mixture that looks the same throughout because one part dissolved.
- dissolve
- to break into bits too small to see and spread out evenly.
- property
- something you can observe, like size, color, or being magnetic.
- separate
- to take a mixture apart into its pieces.
3Look at Figure 1. In one sentence, tell how the solution jar looks different from the plain mixture jar.
Apply Use the Data 20 min
A class made some mixtures and wrote down what they observed. Read Table 1, then answer.
| Mixture | Can you see the parts? | Does it dissolve in water? | Is a part magnetic? |
|---|---|---|---|
| A. Sand + iron filings | Yes | No | Yes (iron) |
| B. Sugar stirred in water | No — looks the same all through | Yes | No |
| C. Sand + water (muddy) | Yes — bits float and settle | No | No |
| D. Small beads + big buttons | Yes | No | No |
4Classify each mixture. Write S if it is a solution (looks the same all through, dissolved) or P if it is a plain mixture you can pick apart.
____ A. Sand + iron filings
____ B. Sugar in water
____ C. Sand + water
____ D. Beads + buttons
5Choose the best way to separate each mixture. Use the evidence in Table 1. Write sift, magnet, filter, or evaporate on the line, then tell which clue helped you choose.
5a. Mixture A (sand + iron filings): ____________________
Clue I used:
5b. Mixture B (sugar in water): ____________________
Clue I used:
5c. Mixture C (sand + water): ____________________
Clue I used:
5d. Mixture D (beads + buttons): ____________________
Clue I used:
6Observation or inference? An observation is something you see or measure. An inference is an idea you figure out. Write O or I for each.
____ a) The sugar water looks clear all the way through.
____ b) The sugar is still in the water even though you cannot see it.
____ c) The iron filings jumped to the magnet.
Explain Claim–Evidence–Reasoning 5–10 min
Question 7. Pick Mixture A (sand + iron filings) or Mixture B (sugar in water). Explain how you would separate it. Use one clue from Table 1 as your evidence.
Sentence starters you may use: "I would separate Mixture ___ by…" · "My evidence from Table 1 is…" · "This works because…"
Close ACE Wrap-Up 5 min
In your own words, what is the difference between a plain mixture and a solution?
Point to one row of Table 1 that is a solution. Write its letter and how you know.
Name one new mixture from home and tell how you would separate it.
Continue Early Finisher optional · ~15 min
Make a separation plan. Imagine a new mixture: salt + sand + iron filings, all dry in one cup. On the back of this page, write the steps in order to get all three parts by themselves. Tell which tool you use for each step (magnet, water, filter, or evaporate) and why.