Grade 8 Science

2. Choose the best answer and
write the letter of your
choice on the space
provided before each
number.

3. _____1. Which of the
following is an
of matter?
A. fire C. heat
B. sound D. energy

4. _____2. Of the phases of
matter, which has the
strongest attractive
forces?
A. Solid C. Gas
B. Liquid D. all of the above

5. _____3. Which of the
characteristics of
makes it an
roofing material?

6. A. It is shiny.
B. It has high density.
C. It can be hammered into
sheets.
D. It can be drawn into fine
wire.

7. _____4. Which of the
following best
describes the
components of
seawater (mixture)?

8. A.They are chemically combined.
B.They have no definite proportion.
C.They combine in a fixed ratio by
mass.
D.They cannot be separated by
physical means.

9. _____5. Gold is to element while
_____ is to compound.
A. ethanol C. aluminum
B. rubbing alcohol D. muriatic acid

10. _____6. Which does not
belong to the group?
A.table salt
B.mayonnaise
C.salt solution
D.halu-halo

11. _____7. Using the table below, which
material do you expect to sink in
water?
Material Density (g/mL)
Aluminum 2.7
Ice 0.92
Iron 7.8
Mercury 13.6

12. A.Aluminum
B.Ice
C.Iron
D.Mercury

13. _____8. Which is a chemical
change?
A.boiling water
B.souring of milk
C.chopping of wood
D.melting of ice cream

14. _____9.
i. Rusting of iron is a
chemical change.
ii. All phase changes
are physical
changes.

15. A.Both are true.
B.Both are false.
C.The first statement is true
while the second is false.
D.The second statement is
true while the first is false.

16. _____10. Jeff placed some
mothballs inside the cabinet.
After some days, the
mothballs disappeared.
What happened to the
mothballs?

17. A.It sublimed.
B.It evaporated.
C.It reacted with air inside the
cabinet.
D.It was dissolved by water
present in air.

26. Follow Up Activity:
Things Around Me

30. A physical property
is

31. Properties depend on size

32. Properties do not depend on size

33. A chemical property is

34. 1. All matter have ______ and will
occupy ________.
2. Matter is made up of __________.
3. Between these particles are
___________.

36. Studying about what matter is
made of involves dealing with
very small “particles” beyond
what your eyes can see.

37. The atomic model
has changed
throughout the
centuries, starting in
400 BC, when it
looked like a billiard
ball.

38. Almost 2,500 years ago, Greek
philosophers, Leucippus and his disciple,
Democritus believed that nature consisted
of two things, “atoms and the void that
surrounds them” (Knieram, 1995-2013).
They believed that “atoms are physically,
but not geometrically, indivisible.”

39. He named the
smallest piece of
matter “atomos,”
meaning “not to
be cut.”

40. To DEMOCRITUS
•Atoms were small, hard particles that
were all made of the same material but
were different shapes and sizes.
•Atoms were infinite in number, always
moving and capable of joining together.

41. This theory was
ignored and
forgotten for more
than 2000 years!

42. •The eminent
philosophers of the
time, Aristotle and
Plato, had a more
respected, (and
ultimately wrong)
theory.

44. •In the early 1800s,
the English Chemist
John Dalton
performed a
number of
experiments that
eventually led to the
acceptance of the
idea of atoms.

45. •All elements are composed of atoms. Atoms
are indivisible and indestructible particles.
•Atoms of the same element are exactly alike.
•Atoms of different elements are different.
•Compounds are formed by the joining of atoms
of two or more elements.
Dalton’s Theory

46. Today, we know that although atoms are
very small, they are not indivisible as
Democritus thought, rather they consist
of still smaller particles, Democritus
was right in one aspect of his belief, that
is, atoms are the smallest particles of
which substances are made.

47. Atoms of most elements have the
ability to combine with other atoms.
When two or more atoms are
combined together in a specific
arrangement, a molecule is
formed.

49. The size of an atom is measured
in angstroms. One angstrom is
a unit of length equal to one ten
millionth of a millimetre.

50. The scanning tunneling microscope
(STM) allows scientists to view and scan the
surface of very small particles like atoms.

51. Pointillist
Painting

53. 1. Oil 6.Wind
2.Hollow Block 7.Ink
3.Electricity 8.Books
4.Crayola 9.Sound
5.Fart 10. Vapor

54. 11. It is a characteristic that can
be observed without changing or
trying to change the substance.

55. 12. It a characteristic that
cannot be observed without
changing a substance.

56. 13-15. Complete the statement
below.
________ is anything that
occupies _____ and has
_____.