Density of glass marbles

  Q1. Volume of 15 marbles = 90 – 65 = 25 cc

  Q2. Mass of 15 marbles = 80 gm

  Q3. Density of 15 marbles = 80 / 25 = 3.2 gm/ cc

  Q4. Density of 1 marble = 3.2 gm/ cc

  Q5. If we use milk in the measuring cylinder in place of water will the volume change? Why?

No. The marbles will displace same volume of milk and same rise in milk level will be observed in the measuring cylinder.

  Q6. If we take small 500 gm iron piece in one hand and big 500 gm cotton pillow in the other, which one will be lighter?

Both will be same as mass is same.

  Q7: If we use 15 cube shaped glass marbles of same mass, will their volume be more or less or same?

Their volume will be same as both mass and density are same.

Arrangement of Iron filings

1.What difference do you observe in the arrangement of iron filings in Case 1 and 2?

In Case 1 (repelling) – There are no iron filings in between the magnets.
In Case 2 (attracting) – Many iron filings get collected in between the magnets.

2.Name 2 uses of permanent magnets.

Doors, pencil box, putting notes on the fridge

3.Name two magnetic materials other than iron

Nickel, Cobalt

Floating and Sinking

Float	Sink
Pumice stone	Stone
Wood piece	Rubber ball
Wax candle	Glass marble
Red plastic piece	Acryllic dice
sponge
Foam piece

Try at Home:

  Q. Will a plastic bottle completely filled with water float or sink in water?

Bar balance and weights

Try to put the unit weights in different ways at different distance. Study different cases and verify the property:
Load x Load Arm = Force x Force Arm

Q3. Which type of lever is used in this experiment? — 1st type

  Q4. Will this experiment give the same result if it is done on Jupiter? Explain your answer.

Yes. Gravity is more on Jupiter but the weight will increase equally on both sides.

  Q5. Can we do this experiment in space where there is no gravitational force? — No, the balance will remain the way we keep it.

  Q6. Observe and find the weight of Piece A — 9 / 4 = 2.25 units

Homework

Identify types of levers in nutcracker, lemon squeezer, tongs, forcep, etc.

Heating floating wax

1.Which wax melted in the first case (heating at the top)? — only the wax at the top
2.Which wax melted in the second case (heating at the bottom)? — both the wax at the top as well as the one at the bottom
3.Explain the above observations.
4.What are sea breezes? When do we experience them?
5.Name three methods of heat transfer. By which the methods can heat be transferred through solids?

Identify Magnet and NonMagnet

1.Find out which of them is magnet. Give explanation.
1.A is a magnet, B is non-magnet. A shows attraction only at the poles and not at centre.

2.What is induced magnetism?
Iron pieces behave linke a magnet when kept in contact with a magnet

3.Give three methods to demagnetize a magnet.
Heating, hammering, keeping in reverse magnetic field

4.What will happen if we keep a magnet in locked wooden drawer for one year? — nothing will happen

Air Pressure

1.Which things work on the principle of air pressure?  – syringe, pichkari, suction ball, dropper, straw

2.Which things do not work on the principle of air pressure? – spring balance, magnetic needle, spirit level

3.Explain how a syringe works.

When the piston is pulled, low pressure is created inside the syringe. So, outside air pushes the water into the syringe (diagram). When piston is pushed, this water gets pushed out.

4. Why does the lid not fall down?

Inside the glass, there is very less air, so very less air pressure. So outside air pressure pushes the lid up. This is sufficient to balance the weight of the water inside the glass. So the lid does not fall

Identify 3 Solutions with Phenolphthalein

  Given: 3 solutions A, B, C – One of them is acid, one is an alkali and one is water

Q 1. Find out the nature of all three solutions.

Q2: Explain your method

B is alkali as Phenolphthalein turned pink in B
B + C became colourless. that means A neutralized B. That means C is acid.
B + A remained pink — so A is neutral

Dropping a Marble into Liquids

1.What do you observe?
Marble sinks fastest in water, then in oil then in corn starch, then in honey.

2.Which property of matter is responsible for this?
Viscosity

3.How is this property related to the transparency of the liquids?
Viscosity is not related to transparency. In the second expt, all the liquids were equally transparent but their viscosity was different.

4.How Is this property related to density of liquid?
(Observe the marble in water and oil.)
Viscosity is not related to density.
Honey (denser) is more viscous than water
Oil (less dense) is more viscous than water

Note: This was an observation-based experiment. You may not have studied about “viscosity”. But still, you can observe the video and draw conclusions about whether density and transparency are related to viscosity or not.

Extraction of Copper from Copper sulphate

 Take some copper sulphate solution in a bowl. Put an iron nail in it. Leave it undisturbed for 2-3 hours.

What we observe – Solution turns green and brown copper deposits are seen on the nail.

What happens?
Iron + copper sulphate — reaction gives —-> ferrous sulphate + copper

Collisions

Concave and Convex Lenses

• Lens A is a convex lens (Object appears bigger)
• Lens B is a concave lens (Object appears smaller)

HW –
• Which type of lens is used in spectacles for myopia in children?
• Which type of lenses are used in telescope?
• Lens which is bulging at the centre and thin at the edges is __________ type.

Flipbook Video

Identify the principle — Persistence of vision

Biology

Odd one out – Penguin (flightless bird)

Brain, skull, skeleton model

Parts of Eye

1.Retina – image gets formed on retina. Rod and cone cells on retina send the signal to brain.
2.Lens: can change its focal length to focus the light on retina.