Students’ Learning Outcomes
· Compare solids, liquids & gases on the basis of shape and volume.
Information for Teachers
· Matter exists in three forms; solid, liquid and gas.
· Solids have fixed shape and fixed volume; liquids don’t have fixed shape but have fixed volume, while the gases don’t have a fixed shape and fixed volume.
· The three states of matter can be explained with reference to water. Solid (ice) liquid (water) and gas (water vapors or steam).
Material / Resources
Book, chair, pencil, jug containing water, cup, register, rubber, glasses of different sizes, balloons having different shapes, textbook
Worm up Activity
· Show the students the following things:
(Books, Chair, Pencil, Copy, Table, Tree, Plate, School bag etc.
· Ask students do these objects have a fixed shape.
(Students’ response: Yes they have fixed shape).
· Can we identify a solid through its fixed shape?
(Students’ response: Yes a solid can be identified by its fixed shape)
· Can we identify a solid change its shape on its own?
(Students’ response: No, solids don’t change their shape on their own)
· Half fill a jug with water. Fill a glass and a cup with water present in the jug. Ask students the following questions:
v Does water has a fixed shape like a glass?
(Students’ response: No)
v Does water get the shape of the container in which it is poured?
(Students’ response: Yes)
· Tell the students that we can’t see air, but we can feel its presence especially under a fan.
· We can also feel the presence of some gases by their smell and color.
· Ask students what type of smell they feel while passing along a sewage pond.
(Students’ response: bad smell). This indicates bad smelling gases are coming out of the sewage pond.
· Place a book on a table and draw a line around the book,
· Shift the book on another place.
· Ask the following question from students.
· What does the space in between the lines tell us?
(Students’ response: The space between the lines is the space covered by the book)
· Ask the students to take different objects like a register, a rubber, a pencil and a glass on a paper and draw lines around these objects. Ask the students the following questions.
v Do all these objects cover the same space?
(Students’ response: No, all these objects cover different space according to their size)
· Take about 250cm water in a jug. Ask students to pour this water into four different vessels, as shown in the following diagram)
· Ask students what does this activity show?
(Students’ response: This activity shows that a liquid doesn’t have a fixed shape. It acquires the shape of the vessel in which it is kept)
· Take two glasses, of different sizes. Fill the smaller glass with water. Now pour water from the smaller glass into the bigger glass.
· Did water completely fill the bigger glass?
· Water occupies all the space of the smaller glass. It doesn’t fill all the space of the bigger glass. Ask students why the bigger glass has not been filled? (Tell them that liquids have fixed volume, they don’t occupy all the available space).
· The amount of space that a liquid takes up in an empty vessel depends upon the quantity of liquid poured into that vessel. A fixed amount of liquid occupies a fixed volume.
· The air inside a balloon has taken the shape of that balloon.
· Ask students, does the air have fixed shape like solid things?
(Students’ response: No).
· Spray a little perfume on one side of the room and wait for some time.
· Ask students sitting at the other end of the room if they can smell the perfume.
· Ask the students, do the vapors of the perfume remain at a certain place.
(Students’ response: No, the vapors have occupied all the available space)
Sum up / Conclusion
· All the solid objects have a fixed shape. They also cover a fixed space.
· Liquids occupy definite volume but they don’t have fixed shape. They take the shape of the container in which they are kept.
· Gases don’t have fixed shape. Like liquids they acquire the shape of the vessel in which they are kept. A glass acquires all the space present in a vessel.
· Ask the students following questions:
v What will happen if you release air present I a cycle tube within a room?
(Students’ response: Air will spread throughout the room)
v Transfer tea prepared in a tea pot to a cup, saucer and a glass. From this experiment what do you conclude about the shape of the liquid tea?
(Students’ response: Being a liquid, tea doesn’t have a fixed shape)
v Show students some coins and ask: What is the shape of coins? Can they change their shape while moving from one hand to another?
(Students’ response: No, being solids, coins don’t change their shape while moving from one hand to another)
v Which state of matter occupies all the available space?
(Students’ response: A gas occupies all the available space).
· Make a table given on next page on the board and ask the students to copy on their note books.
· Ask them to complete the table.