Separate Sand, Salt, and Iron

Approximate time to complete: 30-45 minutes + waiting time + questions and journal time

Experiment Card

Click below to download and print this experiment card:

Purpose

We know that some particles can combine, some particles can mix but stay separate, and some particles do not like to mix at all. We also know that we can separate some particles easily, but some are harder to pull apart once they mix. I wonder how we can combine, and then separate salt, sand, and iron.

Materials

• Petri Dish (with Lid)
• 5mL (1tsp) Sand
• 5mL (1tsp) Salt
• 5mL (1tsp) Iron Filings
• Magnifying Lens
• Tweezers
• Magnet in Plastic Baggie (do not let the iron filings touch the magnet directly – they will be very hard to get off!)
• Beaker(s)
• Water
• 1 Piece Filter Paper

Procedure

1. Put sand, salt, and iron filings into the Petri dish.
2. Put the lid on the Petri dish, and carefully shake to mix (hold the lid on tight!)
3. Using the magnifying glass and your tweezers, try separating the sand, salt, and iron filings – is it easy or hard? How long do you think it would take to separate all of them?

4. Using the rest of the tools (magnet, beaker, water, filter paper) think of a way to separate ALL of the sand, salt, and iron filings. If you’re stuck, check the hints section below. The hints section also has directions on how to fold your filter paper into a cone shape.

Questions & Further Research

1. Can you describe some of the differences between sand, salt, and iron filings? What will they mix with? What will they not mix with?
2. Were you able to separate the iron from the mixture? The sand? The salt? How did you do it?
3. Did you use the scientific method to help you separate this mixture?

Hints

1. Try removing the iron first. Which tool (tweezer, magnet, beaker) might be able to pick up something metal like iron, but will not pick up the sand or salt?
2. Next, try to separate the sand. Which tool (tweezers, magnet, filter) could stop the sand, but let the salt through?
3. Now you are left with salt dissolved in water. How can you get the water out? This one will take time and a little bit of sunshine.

Directions for Folding Filter Paper into a Cone Shape