A bar magnet has no markings to indicate its poles. How would you find out near which end is its north pole located?
We can find out the poles of a bar magnet by keeping them in air with the help of a thread. The one end which shows north direction is the north pole and the other one which shows south direction is south pole.
Second way to find out the poles of a bar magnet. Keep the bar magnets near each other. If both are repelling each other than we can find out that there poles are similar. If they both attracts each other then we can say their poles are on opposite direction because opposite attracts each other.
You are given an iron strip. How will you make it into a magnet?
It was observed that a pencil sharpener gets attracted by both the poles of a magnet although its body is made of plastic. Name a material that might have been used to make some part of it.
Where are poles of a bar magnet located?
How is a compass used to find directions?
A magnet was brought from different directions towards a toy boat that has been floating in water in a tub. Affect observed in each case is stated in Column I. Possible reasons for the observed affects are mentioned in Column II. Match the statements given in Column I with those in Column II.
Column I Column II
Boat gets attracted towards the magnet Boat is fitted with a magnet with north pole towards its head
Boat is not affected by the magnet Boat is fitted with a magnet with south pole towards its head
Boat moves towards the magnet if north Boat has a small magnet fixed along its length
pole of the magnet is brought near its
head
Boat moves away from the magnet Boat is made of magnetic material when north pole is brought near its head
Boat floats without changing its direction Boat is made up non-magnetic material
Column I shows different positions in which one pole of a magnet is placed near that of the other. Column II indicates the resulting action between them for each situation. Fill in the blanks.
Column I Column II
N - N _________
N - _________ Attraction
S - N _________
_________ - S Repulstion
Write any two properties of a magnet.
State whether the following statements are true or false
(i) A cylindrical magnet has only one pole.
(ii) Artificial magnets were discovered in Greece.
(iii) Similar poles of a magnet repel each other.
(iv) Maximum iron filings stick in the middle of a bar magnet when it is brought near them.
(v) Bar magnets always point towards North-South direction.
(vi) A compass can be used to find East-West direction at any place.
(vii) Rubber is a magnetic material.
Fill in the blanks in the following
(i) Artificial magnets are made in different shapes such as __________, __________ and ____________.
(ii) The Materials which are attracted towards a magnet are called________.
(iii) Paper is not a ______ material.
(iv) In olden days, sailors used to find direction by suspending a piece of ___________.
(v) A magnet always has __________ poles.
(a) Which kind of garbage is not converted into compost by the redworms?
(b) Have you seen any other organism besides redworms, in your pit? If yes, try to find out their names. Draw pictures of these.
Rearrange the boxes given below to make a sentence that helps us understand opaque objects.
To walk through a waterlogged area, you usually shorten the length of your dress by folding it. Can this change be reversed?
Do you find that all living beings need the same kind of food?
Name the major nutrients in our food.
Classify the following fibres as natural or synthetic:
nylon, wool, cotton, silk, polyester, jute
Name five objects which can be made from wood.
Why do we need to separate different components of a mixture? Give two examples.
Correct the following statements and rewrite them in your notebook.
(a) Stem absorbs water and minerals from the soil.
(b) Leaves hold the plant upright.
(c) Roots conduct water to the leaves.
(d) The number of petals and sepals in a flower is always equal.
(e) If the sepals of a flower are joined together, its petals are also joined together.
(f) If the petals of a flower are joined together, then the pistil is joined to the petal.
Fill in the blanks:
(a) Joints of the bones help in the ——————— of the body.
(b) A combination of bones and cartilages forms the _______ of the body.
(c) The bones at the elbow are joined by a ______________________ joint.
(d) The contraction of the _____________ pulls the bones during movement.
Do you find that all living beings need the same kind of food?
List all items known to you that float on water. Check and see if they will float on an oil or kerosene.
Write the names of the parts of a flower.
List the common characteristics of the living things.
Rearrange the boxes given below to make a sentence that helps us understand opaque objects.
Why could you not use an elastic measuring tape to measure distance? What would be some of the problems you would meet in telling someone about a distance you measured with an elastic tape?
If a plant has leaves with reticulate venation, what kind of roots will it have?
Draw (a) a leaf, (b) a taproot and (c) a flower, you have studied for Table 7.3.
How will you prove that air supports burning?
The component of air used by green plants to make their food, is ___________.