This document contains information about elements, compounds, molecules, and chemical reactions. It also discusses density, measurement, and experiments. The first section defines elements as substances that cannot be broken down further. Compounds are formed when two or more elements combine chemically. Molecules are the smallest particles that make up elements and compounds. Density is a measure of mass per unit volume. Later sections discuss learning to use measuring instruments like rulers, thermometers and balances. Examples of simple experiments involving sieves, magnets and filters are provided. The last part describes the development of embryos in eggs like chickens and frogs.

1. 3rd term index
science grade 6
s/no date topic sign
1 Elements and compounds
2 Joining up makes the
difference
3 What is everything made
of?
4 More about molecules
5 Density
6 Learning to measure 1
and 2
7 Solving measurement
problems
8 Apparatus
9 Doing experiments
10 Growing up non human
animals.

2. ELEMENTS AND COMPOUNDS

3. ELEMENTS:
• Answer the following:
1. What is an element? An element is a
chemical substance which cannot be
broken into anything more simpler.
2. What is a symbol? A symbol is the
shortened form of the name of the
element.
3. What is a periodic table? It is a list of
all the elements with their symbols on
a chart.

4. 4. How many kinds of atoms are there in
a lump of copper? Explain? Copper
has only copper atom as it is an
element and can’t be broken down
into anything simpler.
5. Most elements are solids, liquids and
gases. Give 2 examples each.
solids liquids gases
Magnesium Mercury Oxygen
Iron Bromine Nitrogen

5. s/no Elements Symbol nature
1 Hydrogen H Gas
2 Helium He Gas
3 Lithium Li Solid
4 Beryllium Be Solid
5 Boron B Solid
6 Carbon C Solid
7 Nitrogen N Gas
8 Oxygen O Gas
9 Florine F Gas
10 Neon Ne Gas
11 Sodium Na Solid
12 Magnesium Mg Solid
13 Aluminium Al Solid
14 Silicon Si Solid
15 Phosphorus P Solid
16 Sulphur S Solid
17 Chlorine Cl Gas

6. Compounds:
1. What is a compound? A compound is
formed when two or more substances
[elements] are mixed together by
joining up [combined chemically] e.g
Na + Cl = NaCl
2. What is a mixture? A mixture is
formed when two or more substances
are mixed together without joining up
[combined physically] e.g sand and
water; water and oil.

7. 3. What elements are joined up in:
a) Sand [Silicon dioxide(SiO2)= Silicon
and Oxygen
b) Common salt [Sodium Chloride
(NaCl)] = sodium and chlorine
c) Water [Hydrogen oxide (H2O) =
Hydrogen and Oxygen
d) Copper iodide or copper iodine (CuI)
= copper and Iodine
e) Iron Sulphide (FeS) = Iron and Sulphur

8. Class activity:
Make a table to show the difference
between element, compound and
mixture
Element Compound Mixture
Simple chemical substance Two or more elements
combined chemically
Two or more elements or
substances mixed together
without joining
Can’t be broken into simple
substances
Can be broken
Can’t be separated easily
Can separated easily
Examples; carbon, Hydrogen Example; sand, water Example; mixture of Iron
and Sulphur.

9. JOINING UP MAKES THE DIFFERENCE
ANSWER THE FOLLOWING:
1. How is water different from the elements which
makes it up? The elements hydrogen and
Oxygen are both in the form of gas, they lose
their identity when they combine to form a
compound.( water in liquid form).
2. Do you think milk contains Calcium as an
element or compound? It is present as a
compound since milk contains 87% of water.
3. What happens when;
a) Calcium is put in water: it bubbles and fizzes in
water.

10. b) Phosphorus is exposed to dry air: it
catches fire.
4a. Name the elements which makes up
Calcium Phosphate, where is it found?
Calcium, Phosphorus and Oxygen are the
elements that makes up Calcium
Phosphate, it is found in bones and
teeth.
b. What would happen to our teeth if they
are made only from the element Calcium?
Our teeth would bubble and fizz in water as
calcium reacts in water.

11. Home work
Find out the uses of the following
elements (mineral) present on our body.
1. Iron: we need it to transport oxygen
in our body
2. Sodium: it helps in blood pressure
and normal fluid balance in the body.
3. Potassium: it helps in building
proteins and metabolize
carbohydrates.

12. 4. Calcium: it helps in building bones and
teeth and keeping then healthy. It is
found in diary.
5. Iodine: it controls the body’s
metabolism and many other important
functions. It is found in sea vegetables
and food

13. WHAT IS EVERYTHING MADE OF?
Answer the following:
1. What is a molecule? A molecule is
the smallest particle of a substance
that can exist independently. A
molecule is a group of atoms joined
together. E.g water, has two hydrogen
atoms and one oxygen atom (H2O),
carbon dioxide, has one carbon atom
joined to two oxygen atoms (CO2),

14. 2. What is an atom? an atom is the
smallest particle of an element that takes
place in a chemical reaction. It can’t exist
independently.

15. 3. What are solids, liquids and gases
made up of? They are made up of
tiny particles called atoms and
molecules.
4. Why does a balloon go down quickly if
a pin is pricked in it? The air escapes
from it easily and the balloon goes
down.

16. 5. Air slowly escapes from a balloon
even when it’s tightly tied. Why?
a) Balloon rubber behaves as if it has
very small holes in it.
b) Air is made up of millions of tiny
particles moving about
c) These tiny air particles are small
enough to escape through the holes
in the balloon.
d) Draw diagram from notebook.

17. MORE ABOUT MOLECULES.
Answer the following:
1. What is meant by diffusion? The
movement of molecules from areas
of HIGH concentration to areas of
LOW concentration.

18. 2. Why does gases spread easily
through each other? Gases spread
easily through each other because
the space between the molecules in
gas is more and the molecules are
moving.
3. Do molecules move fast in gas or
liquid? explain. Molecules move fast
in gases than in liquids because the
molecules in gas are far apart and
free to move about than in liquids.

19. 4. Adding 50cm3 water to 50cm3 of
alcohol, gives a volume of 95cm3.
Explain why? When alcohol and
water are mixed, water molecules fit
into some of the spaces between
alcohol molecules, this makes the
volume less than expected.
5. How far could gas molecules travel in
one second? 100-2000m/s

20. the students were asked to predict what would
happen if 50mL of water was mixed with
another 50mL of water. We then mixed two
graduated cylinders, each containing 50mL of
water into a 100mL graduated cylinder. The
result was 100mL of water total.
The students were then asked what would
happen if 50mL of water and 50mL of ethanol
were mixed. We again mixed 50mL of water
with 50mL of ethanol. The result was a total
volume of approximately 96mL. We asked the
students to explain this
500mL of rice and mixed it with another
500mL of rice. We explained to the students
that the rice represented the water molecules.
The result was 1000mL of rice. We then took
500mL of rice and 500mL of rigatoni noodles
and mixed them. The rigatoni noodles
represented the ethanol. The result was
approximately 650mL to 700mL.

21. DENSITY
Answer the following?
1. What is density? The density of a
substance is a measure of mass per
volume of the substance.

22. 2. What is the unit of density? The unit
is grams per cubic centimetre written
as g/cm3 or gcm-3
3. How does some objects float and
some sink in water? If the density of
object is more than water, it sinks. If
the density of object is less than
water, it floats on water. Density of
object makes it float or sink.
4. Why do hot air balloon rise?

23. Hot air has low density than cold air, so
they rise.
5. It is easier to float in sea water than a
lake, why? This is because, sea water
is denser than the water in the lake.
6. On what does the density of a
substance depend? Density depends
on;
 the mass of its atoms and molecules
volume

24. 7. Why does gold have high density? It
is made up of heavy atoms and they
are closely packed.
8. Why does gases have very low
densities? Gas molecules spread out
to occupy large volume with lots of
empty space. 1cm3 of any gas is very
light.

25. Look at density ladder [draw from notebook]
a) Why does oak wood float on water
but not on paraffin? because oak
wood is less dense than water and
more dense than paraffin.
b) Suggest densities for X and Y
explaining each choice. X is less
dense than water. Y is denser than
water.
c) The density of nylon is 1.1g/cm3.
where on the ladder would a piece of
nylon float? Explain your answer.

26. In Perspex, Y, copper and mercury.
Because it is less dense than these
substances.

27. Solved Problems on Density
1. Find the density of the following:
a. Brass nut, mass 34g, volume 4cm3
D = m/v =34/4=8.5g/cm3

28. b. A cork mass 2g, volume 8cm3
D = 2/8 = ¼ = 0.25g/cm3
2. Iron has density 7.8g/cm3, mass = 7.8g. Find
volume. V = m/d = 7.8/7.8 = 1 cm3
3. You have a rock of volume of 15cm3 and a mass
of 45g. What is the density?
D = M/V = 45/15 = 3g/cm3
4. Calculate the density of 500g rectangular block
with dimension L=8cm, w=6cm, h=5cm.
volume=LxBxH =8x6x5=240cm3
D=m/d=500/240=2.08g/cm3

29. 5. Oak wood 1800g of mass, 2000cm3 of
volume. Find the density of the oak-
wood? [class work]
d=m/v = 1800/2000 = 0.9g/cm3
6. If a 96.5g piece of aluminium has density
of 2.7g/cm3. what is the volume?
v = m/d = 96.5/2.7 =965/27 = 35.7g
7. Calculate the mass of a liquid with a
density of 3.2g/ml and volume of 25ml
m = d X v = 3.2 x 25 = 80g

30. LEARNING TO MEASURE 1 AND 2
Answer the following:
1. Name your 5 senses: the 5 senses are
seeing, hearing, tasting, touching and
smelling.
2. Why do scientist use measuring
instruments whenever they can?
Scientist use measuring instruments
whenever they can because we can’t
depend on our senses for exact
measurement.

31. 3. What could you measure using:
a) stop watch, clock, watch: Time [hour,
minutes, second]
b) Thermometer: Temperature [degree
Celsius oC, Fahrenheit F and kelvin K]
c) Measuring cylinder, beaker: volume of
liquid [lxbxh, cm3, m3]
d) Balance : Mass [kg, g, mg]
e) Ruler, meter sticks and tape: Length
[km, m, cm, mm, feet, miles, yards]

32. 4. Which units are used to measure:
a. volume: the units to measure volume
are millilitre(ml), litres(l), cubic
centimetre(cm3), cubic metre(m3).
b. Mass: units of mass are gram(g) and
kilogram(kg)
c. Length: units used to measure length
are metre(m), millimetre(mm) and
kilometre(km)
d. Time: the units of time are seconds(s),
minutes(m) and hour(h).

33. e. Temperature: units to measure
temperature are degree Celsius(oC),
Fahrenheit(F) and kelvin(K)
5. Why can’t you depend on your
senses to find out the temperature
of the air? It is because the same air
may feel warm to one person and
cold to another.
6. What is meant by:
a. Volume: volume of an object is the
space taken up by it.

34. b. Temperature: temperature of an
object means the degree of hotness
of the object
c. Mass: mass of an object is the
amount of matter contained in it.
7. What are the reading on the
instruments shown: [class activity]

37. Individual project
1. Make a list of 5 measuring
instruments used in your home
2. Stick pictures of the following:
a. Ruler
b. Thermometer
c. Stopwatch
d. Measuring cylinder
e. Balance

38. SOLVING MEASURMENT PROBLEMS
Answer the following:
1. How could you find the volume of a
pebble? By using a measuring cylinder
a. Put some water in the measuring
cylinder and measure the volume
b. Drop the pebble and measure the
volume again
c. The difference in the volume is equal to
the volume of the pebble.
final volume – initial volume = volume of pebble.

40. 2. What is special about pendulum
swing? In the case of pendulum
swing, the time for one swing is
always the same
3. How would you find time for one
swing of the pendulum if the time
taken is 12sec for 10 swings?
time taken for 10 swings = 12 sec
time taken for 1 swing = time for 10 swings/ no of swings
12/10 = 1.2 sec.

41. 4. Find the average mass of 1 nail, if 50
nails have a mass of 175g.
m= m of 50 nails/ no of nails =
175/50 = 3.5g
5. How can you make a simple
pendulum? We can make a simple
pendulum from a string and an iron
bob

43. Apparatus
Measuring cylinder.
Measuring volume
Beaker.
Measuring liquid
Test tube Test tube holder
Conical flask Round flask Flat bottom flask funnel

44. Wire gauge
Tripod stand
pipette
burette Retort stand Laboratory dish

45. Doing experiments
Answer the following:
Experiment 1:
a) What happens when sand and gravel
are shaken in the sieve? A sieve is
used to separate small particles from
large ones. Sand passes through the
sieve. Gravel settles at the bottom of
the sieve.

46. b) Why does this happens? Because the
size is different;
i. A sieve is a shallow tray with holes in
it
ii. The mixture is placed in the sieve
which is shaken from side to side
iii. The sand particles are much smaller
than gravel and fall through the
holes in the sieve.

48. Experiment 2
a. What happens when the magnet is
moved through the mixture of iron
powder and sand? Iron powder will
stick to the magnet.
b. Why does this happen? Iron is metal,
it has magnetic property.

50. Experiment 3
a. What happens when chalky water is
put into the filter funnel? Chalk is
insoluble in water. The filter paper
separate the chalk that hasn’t
dissolve in water

52. Growing up non human animals.
Egg when laid 10 days later young adult

53. Look at the diagram and answer the
following:
1a. How does the embryo get oxygen it
needs? The oxygen it needs travels
through the egg shell.
b. Why does the egg yolk become
smaller in the diagram? The embryo
gets it’s food from the yolk so as the
chicken grows, the size of the yolk
becomes smaller.

54. c. How does the embryo get food? The
embryo gets food from the yolk.

55. Look at the diagram and answer the
following: [class activity 2]
1a. Write the name of frog’s egg. Frog
spawn.
b. Name the larvae stage of frog.
Tadpole
c. What is the gestation period of frog?
6-21 days

56. Answer the following:
1. Define gestation period? The time
between fertilisation of the egg to the
birth of a young adult is called
gestation period.
2. What is common between embryo of
different animals?
They all grow from fertilised egg which
divides to produce more cells
They all need food and oxygen to grow
They are all surrounded by water as
they grow.

57. 3. How does human embryo get food
and oxygen? From the mother’s blood.
4. How do different embryo grow in
different ways?
Some embryo develop inside
the egg
Some embryo develop inside
the mother’s worm
Some embryo gets food from
egg’s yolk and oxygen passes
through the shell
Some get food and oxygen
from the mother’s blood
Most embryo grow into adult Some embryo grow into
larvae and larvae changes
into adult. E.g frog, insects
etc