What happens when we mix liquids?
Mix it up! What happens when you mix different liquids? Learn about the properties of liquids as you get mixing.
What You Need
- Several types of liquids from around your home, such as: milk, cooking oil, apple sauce, spaghetti sauce, water, tea, coffee, liquid soap, shampoo, body lotion, bath bubbles, hair gel, juice, ketchup, fruit drink, chocolate syrup, pancake syrup, molasses, honey, vinegar, soya sauce, lemon juice, etc.
- 3 or more small plastic cups (transparent is best)
- 3 or more spoons for mixing
Safety First!
- Provide adult assistance for young children to pour liquids.
- Ensure young children do not taste or ingest the liquids used in this activity.
- Dispose of all the liquids used in this activity when finished.
- Do not use household cleaning products or other hazardous liquids for this activity.
What to Do
- Set up a test area with the cups and spoons in an area where spills are not an issue, such as the kitchen table.
- Bring your test liquids to the test area.
- Pour a small amount of two different liquids together into one cup and mix them together with a clean spoon. What happens to the liquids? Did the two liquids become one new liquid, or do they remain separate liquids and form layers? Do they change colour, texture, smell, foam up, etc.?
- Try pouring new combinations of liquids into the cups, predicting what will happen before you begin mixing. Be sure to wash the cups and spoons between combinations. Did any combinations surprise you? Were there any unexpected results?
Discovery
When two liquids combine to form a new liquid, we call the liquids “miscible.” When two liquids do not mix together and instead form layers, we call them “immiscible.” The chemical properties of the liquids will determine if they will mix or not. Those with similar chemical properties will mix; those with different properties will not mix.
Oil and water are good examples of immiscible liquids. Oil floats on water because it is less dense, meaning it has less mass than the same amount of water. Density is the amount of material in a certain space. A brick has much more material packed into it than a same-sized piece of foam. As a result the brick is “more dense” and is heavier than the brick-sized piece of foam. Oil has fewer particles packed into it than a same-sized sample of water; therefore it is lighter.
A liquid is a state of matter that is neither a solid nor a gas. In a solid, the molecules are very tightly spaced. In a liquid, the molecules are more loosely spaced. In a gas, the molecules are very far apart. Liquids do not have a fixed shape; they take on the shape of the container they are in. Most liquids can also flow and form drops.
Understanding the properties of liquids can help us know how to use them. Salad dressing, for example, is a mixture of oil and vinegar, with some herbs and spices to add flavour. Since we know that oil and water do not mix, we have to shake a bottle of salad dressing before using it. This makes the dressing a mixture for a short time so that we can get even amounts of the oil and vinegar on the salad. Once you stop shaking the bottle, the oil and vinegar will quickly separate again. Many store-bought salad dressings contain a substance known as an emulsifier, which will help keep immiscible liquids mixed together for longer periods.
Since oil always floats on water, we can use this property to help separate liquids. When you make gravy, the meat drippings (or stock) are a mixture of meat juices (water-based) and fat (oil). If you let the drippings sit still, you can remove the fat on top with a spoon. This makes the gravy healthier. You can also use a handy kitchen gadget called a gravy separator to remove the excess fat.
- Look at the liquids you have in your fridge at home or at the grocery store. Which ones have layers? What does this mean?
- Try using a gravy separator to separate a mixture of oil and water.
- Watch Steve Spangler Science create a 9-layer density column with seven objects added that float at different densities: Amazing 9 Layer Density Tower - Sick Science! #012 (Video – 1:24 min)
- The different properties of oil and water can be used to separate the fat from gravy. This chef shows you how: 60-Second Video Tips: 3 Easy Ways to De-Fat Stock (Video – 1:25 min.)
For more information on this topic check out these Let's Talk Science resources:
- Properties of Liquids and Solids (Lessons) - Students develop and apply observing, comparing & contrasting and predicting skills as they explore the properties of common liquids and solids.
- States of Matter (Backgrounders) - Learn about the states of matter, as well more about one state in particular - gas!
- Is it a solid or a liquid? (Hands-on Activities) - Make some goop that has the properties of a liquid and a solid.
What’s happening?
When two liquids combine to form a new liquid, we call the liquids “miscible.” When two liquids do not mix together and instead form layers, we call them “immiscible.” The chemical properties of the liquids will determine if they will mix or not. Those with similar chemical properties will mix; those with different properties will not mix.
Oil and water are good examples of immiscible liquids. Oil floats on water because it is less dense, meaning it has less mass than the same amount of water. Density is the amount of material in a certain space. A brick has much more material packed into it than a same-sized piece of foam. As a result the brick is “more dense” and is heavier than the brick-sized piece of foam. Oil has fewer particles packed into it than a same-sized sample of water; therefore it is lighter.
A liquid is a state of matter that is neither a solid nor a gas. In a solid, the molecules are very tightly spaced. In a liquid, the molecules are more loosely spaced. In a gas, the molecules are very far apart. Liquids do not have a fixed shape; they take on the shape of the container they are in. Most liquids can also flow and form drops.
Why does it matter?
Understanding the properties of liquids can help us know how to use them. Salad dressing, for example, is a mixture of oil and vinegar, with some herbs and spices to add flavour. Since we know that oil and water do not mix, we have to shake a bottle of salad dressing before using it. This makes the dressing a mixture for a short time so that we can get even amounts of the oil and vinegar on the salad. Once you stop shaking the bottle, the oil and vinegar will quickly separate again. Many store-bought salad dressings contain a substance known as an emulsifier, which will help keep immiscible liquids mixed together for longer periods.
Since oil always floats on water, we can use this property to help separate liquids. When you make gravy, the meat drippings (or stock) are a mixture of meat juices (water-based) and fat (oil). If you let the drippings sit still, you can remove the fat on top with a spoon. This makes the gravy healthier. You can also use a handy kitchen gadget called a gravy separator to remove the excess fat.
Investigate further
- Look at the liquids you have in your fridge at home or at the grocery store. Which ones have layers? What does this mean?
- Try using a gravy separator to separate a mixture of oil and water.
- Watch Steve Spangler Science create a 9-layer density column with seven objects added that float at different densities: Amazing 9 Layer Density Tower - Sick Science! #012 (Video – 1:24 min)
- The different properties of oil and water can be used to separate the fat from gravy. This chef shows you how: 60-Second Video Tips: 3 Easy Ways to De-Fat Stock (Video – 1:25 min.)
For more information on this topic check out these Let's Talk Science resources:
- Properties of Liquids and Solids (Lessons) - Students develop and apply observing, comparing & contrasting and predicting skills as they explore the properties of common liquids and solids.
- States of Matter (Backgrounders) - Learn about the states of matter, as well more about one state in particular - gas!
- Is it a solid or a liquid? (Hands-on Activities) - Make some goop that has the properties of a liquid and a solid.