SAY THE NUMBERS YOU CAN SEE!

CHAPTER 1:

THE WORLD THROUGH OUR SENSES

SENSORY ORGANS & THEIR FUNCTIONS

Sensory organ Types of sense Stimulus detected

Skin TouchTouch, pressure,

pain, cold and heat

Nose Smell Chemical substances

Tongue Taste Chemicals

Ear Hearing and balance Sound

Eye Sight Light

Relationship between stimuli and senses to sensory organs

SKIN

Touch

Touch, pressure, pain,cold heat

EARS

Hearing and balanc

esound

s

TONGUE

Taste

chemicals

NOSE

Smell

Chemicals

substances

EYES

Sight

Light

Experiment 1.1:

Sensory organs and their function

EXPERIMENT

Objective : To show the relation between the five sensory organs and their stimuli.Materials:Icing sugar, fine salt, vanilla essence, oats, acid chlorideApparatus:Test tubes, evaporating dishes, litmus paper, beaker, dropperProcedures:•The activities given in the table below are carried out and observations are recorded.•Table 1.1 to be completed to show the relation between the sensory organs and their stimuli.

Activity Observation

(a)A few drops of chloride acids

are added to litmus paper.

(b) Three beaker of the same size are filled

with different volumes of water. Then the

edge of each beaker is tapped with glass

rod

(c) 10cm3 of water and a few drops of

vanilla essence in 10cm3 of water are

placed in separate test tubes and sniffed

(d) Dry oats and wet oats placed in separate

evaporating dishes are touched with the

fingers and compared.

(e) Fine salt and icing sugar, placed on

separate evaporating dishes, are tasted

and compared.

DISCUSSION

Activity Observation

(a)A few drops of chloride acids

are added to litmus paper.

Litmus paper changes to red.

(b) Three beaker of the same size are filled

with different volumes of water. Then the

edge of each beaker is tapped with glass

rod

Sounds are heard.

(c) 10cm3 of water and a few drops of

vanilla essence in 10cm3 of water are

placed in separate test tubes and sniffed

Vanilla essence gives a fragrant smell.

Water does not have any smell.

(d) Dry oats and wet oats placed in separate

evaporating dishes are touched with the

fingers and compared.

Wet oat re starchy.

Dry oat are powdery.

(e) Fine salt and icing sugar, placed on

separate evaporating dishes, are tasted

and compared.

Salt tastes salty.

Sugar taste sweet.

Activity Sensory

organ

Sense Stimulus

(a) Eye Sight Light

(b)

(c)

(d)

(e)

CONCLUSION

5 Sense that detected by the 5 sensory organs are as follows:

1.Skin – touch, heat, cold, and pressure

2.Nose – smell3.Tongue – taste4.Ears – sounds5.Eyes - light