Materials, Properties and Uses (Lesson 1)

 FOCUS QUESTION

What are some properties of common materials and their everyday uses?

SPECIFIC OBJS.

1.       Identify correct and safe ways of using, storing and disposing materials and household items.

2.       List some properties of materials that determine the choice of objects for specific purpose in everyday life.

3.       Work cooperatively in groups

CONTENT SUMMARY

Materials exist as solids, liquid or gases. Materials/objects have different properties, such as transparency absorbency, strength, magnetic property, and heat conductivity, which determine their everyday use.

Safety symbols, hazard symbols or safety labels are meaningful and recognizable graphical symbols that warn of or identify hazards associated with the location or item.

Improper disposal of some materials can affect the environment.

Materials can undergo reversible or irreversible changes. Irreversible changes cannot be undone and form new materials. Reversible changes can be undone. Reversible and irreversible changes can be useful in everyday life.

Substances can change their state by heating and cooling.  Melting, freezing, evaporation and condensation can cause materials to change state.

ENGAGE

Students I want you to examine some unlabeled warning signs (hazard symbols) and tell what they are depicting and where you have seen them. Discuss in your groups why you think these signs are important. Can you tell of other warning signs you may have known and seen before even at school. Eg expiry date on food stuff etc.

EXPLORE

Examine this Youtube video clip which shows some hazard signs and their meanings.

Video : hazard signs

Examine these  variety of labels from household items and examine them for instructions for use, warning signs (hazard symbols), expiry date, ingredients, storage and disposal. In groups, you will prepare a checklist and record the information on the different types of products.

EXPLAIN

Share your findings with the class, noting the types of instructions given for certain products eg, medicine, insecticide containers, etc. (Key points will be written on the chalkboard.. Students will read the information together from the chalkboard, paying attention to pronunciation and inflectional endings).

EXTEND/ELABORATE

Now I want you to make statements about the importance of each type of information, paying special attention to use, storage and disposal.  Share your information with the class, and critique each other’s work. 

EVALUATE

Answer questions below.

1.  Mrs. Black felt sick and visited the doctor. She got a prescription and she filled it at the pharmacy. Mrs. Black was too busy to read the direction and so she quickly took two of the tablets. The next day, she totally forgot to take her medication so she doubled the doze the day after. She found out that she felt feint after wards, so she decided to read to see if there were any side effects and also if she was taking the right dosage.

In your groups, use an appropriate media to show:

(a)    Where Mrs. Black went wrong?

(b)   Highlight why it is important to follow directions.

2. Mother bought an item at the store and saw the sign below.

(a) Which of the following defines the sign?

          

¡  gas under pressure      ¡  Fatal       ¡ irritant          ¡  flammable

    (b) Write one advice that you would give to your mom. ______________________________

3. Match the signs below with their meanings.

                          SIGNS                                                                MEANINGS

	fatal
	explosive
	corrosive
	irritant (eye, skin)
	flammable

4. 

  

5. Sally, a grade 5 student, is curious as to why these hazardous chemicals are stored in the types of containers above since they are so hard to disintegrate. Explain to her why they have to be so stored.

__________________________________________________________________________________________________________________________________________________________________

6. For each of the following, indicate by shading under the column whether you agree or disagree with the statements about materials, properties and uses.

STATEMENTS	AGREE	DISAGREE
Hazardous symbols are not relevant and do not have to be highlighted on materials since instructions are already given	0	0
It is important to use certain types of materials to store hazardous substances.	0	0
Some household products are considered dangerous that workers have to wear safety gear like gloves and masks	0	0
Some materials will hurt the environment if they are not disposed of properly.	0	0
Biodegradable materials are materials that will not break down in soil.	0	0
	0	0