To begin with mixtures, lets think about what we ate yesterday. Make a list of everything
you ate for breakfast, lunch, tea and dinner. Remember to include drinks too!
Download the following table, (activity_1.zip)
these questions will help you:
Breakfast:
- Did you drink milk or chocolate milk?
- Did you add sugar, honey or sweeteners?
- Did you eat white or wholemeal bread, toast or biscuits?
- Did you eat fruit or juice?
Lunch
Write down all the ingredients that you remember. If you don’t know how the food was prepared,
ask a friend or an adult or ask the cook. Find out if they added salt, oil, vinegar or any other condiment and write in down
too.
Do the same with tea and dinner.
When you finish, save the list..
Your list should look something like this:
Breakfast |
Drink:
Chocolate milk
| Ingredients:
Cocoa
Milk
Sugar
|
Food:
Biscuits
| Ingredients:
Flour
Sugar
|
Think about your breakfast… Did you use powdered cocoa? How did you make it? Did you put the cocoa in
the cup, add milk and then sugar? Did you mix everything together? How many ingredients were in your drink? While you were
drinking it, could you identify the milk or the sugar?
Lunch |
Drink:
Water
| Ingredients :
Water
|
Starter
Salad
| Ingredients:
- Tomatoes
- Green peppers
- Onions
- Asparagus
- Olive oil
- Vinegar
- Salt
|
First course:
Macarroni carbonara
| Ingredients :
- Macarroni
- Bacon
- Salt
- Cream
- Oregano
|
Second course:
Veal and chips |
Ingredients:
- Veal
- Salt
- Parsley
- Potatoes
|
Dessert:
Meringue milk
(see attached recipe: recipe.pdf)
| Ingredients:
- Milk
- Sugar
- Cinnamon
- Lemon
- Egg
|
Let’s think about salad. What are the ingredients? Tomatoes, peppers, onions, asparagus, oil, vinegar
and salt. But how many can you identify? Only tomatoes, peppers, onions and asparagus, because the dressing, oil, vinegar
and salt are mixed in with the other ingredients.
The cocoa for breakfast and the salad for lunch are both mixtures.
So, what is a mixture?
It is the combination of two or more substances. But here are two very different mixtures
In the salad you can clearly see and distinguish some of the different components. This is aheterogeneous
mixture, (where the word “hetero” means “different” because each part of the mixture is different). Heterogeneous
mixtures consist of visibly different substances that can be seen with the naked eye and with a microscope.
In chocolate milk, it is not possible to see or distinguish the components. We see the combination
of ingredients as one substance. This is a homogenous mixture (where “ homo” means “same”) it has the same uniform
appearance and composition throughout. We cannot distinguish the different components with the naked eye or with a microscope
Do the following exercise to distinguish homogeneous mixtures, heterogeneous mixtures and pure substances: Types of mixtures