Overview



Overview

Campers will learn about civil engineering, chemistry, matter and reactions in this activity while making their own plastic figurines with milk, vinegar and heat.

|Topic (s) |Chemistry, Civil engineering |

|Grade Level |3-6 |

|Cost (per camper) |0.28 |

|Time (preparation and activity) |35 min |

|Complexity |Easy |

Ontario Curriculum Links

Understand Matter and Energy: Grade 5 – Properties of and Changes in Matter

Big Ideas:

• There are three states of matter

• Matter that changes state is still the same matter

• Physical change refers to the fact that a substance can be changed from one form to another

• Chemical change implies the formation of a new substance

Specific Expectations:

• follow established safety procedures for working with heating appliances and hot materials

• measure temperature and mass, using appropriate instruments

• use appropriate science and technology vocabulary, including mass, volume, properties, matter physical/reversible changes, and chemical/irreversible changes, in oral and written communication

• identify matter as everything that has mass and occupies space

• identify properties of solids, liquids, and gases

• explain changes of state in matter

• describe physical changes in matter as changes that are reversible and irreversible

• distinguish between a physical change and a chemical change

Understand Matter and Energy: Grade 2 – Properties of Liquids and Solids

Big Ideas:

• Materials that exist as liquids and solids have specific properties.

• Liquids and solids interact in different ways

Specific Expectations:

• assess the impacts of changes in state of solids and liquids on individuals and society

• use appropriate science and technology vocabulary, including clear, opaque, runny, hard, greasy, and granular, in oral and written communication

• follow established safety procedures during science and technology investigations

• investigate, through experimentation, interactions that occur as a result of mixing and/or dissolving liquids and solids (e.g., salt and water, sand and water), liquids and liquids (e.g., oil and water), and solids and solids (e.g., salt and sand)

• describe the properties of solids (e.g., they maintain their shape and cannot be poured) and liquids (e.g., they take the shape of the container they are in and can be poured)

Theory & Background Information

Chemistry

Chemistry is the branch of science that studies matter and its interactions. Chemists often study mixing substances (also called chemicals) together in order to form new substances.

Chemical Reactions

A chemical reaction is a change that takes place when two or more substances (also called reactants) are mixed together to form a new substance (also called a product). Some signs of chemical reactions are: the forming of gas/bubbles, a temperature change, and the formation of a precipitate (something solid emerges from two liquids). A very common example of a chemical reaction is baking a cake. You mix eggs, butter, sugar, flour and water together, add heat from the oven and in no time you have a new product: a cake.

Chemical reactions occur when two or more molecules collide with each other at the right speed, angle, and rotation, with enough energy to create the new molecule. These collisions cause transformations/reactions. Some ways to speed up chemical reactions include:

1) Add heat - objects move faster when heated, therefore more collisions

2) Add friction - increases frequency of molecule collisions

3) Decrease volume - substances in a smaller container will be kept more centralized which increases the chance of molecule collisions

Plastic Milk

Milk contains a protein called casein. Cheese, made from milk, is mostly casein. Casein is also used to make plastic, glue, and paint. Cooking milk with vinegar causes the casein to separate from the other substances in milk and become a moldable substance similar in characteristics to plastic.

Materials

Per Group of 5:

• Paint to paint their figurines

• White glue or hot glue

Per Camper:

• Vinegar 1 tablespoon

• Milk 2cups

• Paint brush

Per Camp:

• Hot plate to warm milk

• Pot

• Strainer

• A roll of Paper towel

Risk Factors

✓ Allergies to milk

✓ Hot plate

Location

• Inside where there are tables and outlets for the hotplate

• It’s good to have windows or airflow because it can get smelly (because of the curdled milk)

Emergency Contingency

Preventative

1. Don’t let campers touch the pot or hotplate when in use.

2. Don’t let campers eat the casein.

Reactive

1. If the camper eat the casein, have them drink water

2. If the campers are burned, run their burn under cold water

Procedure

Preparations

No Preparations

Introduction

1) Ask the campers if they know what chemistry is. Explain that chemistry is a type of science that studies matter and interactions. Chemists are the scientists that work with different substances and mix different chemicals in order to create new substances.

2) Tell the campers that a chemical reaction is when a change takes place in two or more substances and then a new substance is created.

3) Ask the campers if they can think of any chemical reactions that they may have done before. (Most campers will respond that when baking a cake, they are taking two or more substances and then when heat is added, a new substance is formed.)

4) Tell the campers that some of the main signs that chemical reactions have occurred are gas/bubbles, a temperature change or the formation of a precipitate (something solid emerges when two liquids are mixed together)

5) Explain to the campers that chemical reactions occur when two or more molecules collide at the right speed, angle and rotation in order to create a new molecule.

6) Ask the campers if they can think of the three main ways that chemical reactions can speed up. They should reply that heat, friction and decreased volume speed up interactions.

7) Tell the campers that today they will be chemists and will be using milk and vinegar in order to create their own plastic creatures. Tell the campers that by using heat, casein, a protein in milk separates from the solution and when drained, it can be molded into different shapes. When it dries, it will become a plastic therefore creating a new substance out of two prior substances.

Activity

1. Organize the campers so they can view the process of mixing the different substances. Get one camper to add 2 cups of milk/camper.

2. Ask another camper to be your special helper by adding 15 mL of vinegar/camper.

3. Over low heat, stir the mixture until a white rubbery material forms in the milk and tell the campers that the rubbery material is the casein. This should take approx. 10 min.

4. Take the strainer and line it with one paper towel and place it above a bowl. Slowly pour the mixture into the strainer.

5. Squeeze the milk through the strainer until the rubbery casein is left.

6. Separate the casein into equal sized globs for each camper and ask them to return to their seats.

7. Hand out a glob of casein to each camper.

8. Let the campers create the figurine that they want to make. It may be hard to attach the pieces of casein so campers can make pieces of their figurine and glue them together when they dry.

9. Set up an area with labels of each campers name for the casein to dry.

10. Let the shapes sit for 2 days to dry and harden before painting.

11. When dry, get the campers to decorate with paint.

Activity Accommodations and Extensions

Accommodations

• If a camper is having difficulties with completing this activity, an instructor can assist them in shaping their casein.

• If extra time is needed to complete this activity, the instructors can begin heating the solution prior to the lesson in order to ensure that there will be little downtime while waiting for the casein to separate.

Extensions

• If campers complete this activity early, they can attempt to try to make a more unique and complex figurine with their casein.

Safety Considerations

Consideration should be taken when using an element in order to ensure that campers and instructors do not get burnt. As well, instructors should make sure that campers do not put the casein into their mouths. Also, leaders should be aware of any milk allergies.

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Resources

Banting C 2007 Plastic Milk Creatures write-up

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