WhatsApp Posts for 6th Homi Bhabha Online Class

# Welcome

Welcome to Online Homi Bhabha Class! We will use this group for all communication related to our online class.

Happy Learning Science!

– Rahul and Udita Ogale

# Admin

This is an admin controlled group. And we need to maintain a good level of discipline while posting.


  1. All irrelevant posts
  2. All unnecessary ‘ok’, ‘good morning’, ‘thumbs ups’, ‘thanks’, ‘symbols’ etc.
  3. ‘Add this number’ requests
  4. Long messages with formulas, tables, or unnecessary information or fwd info.

Only Science-related posts please. Kindly avoid discussion about other topics on the group. Members to please use personal chats to discuss other topics. To keep the group effective and manageable, we should try to follow discipline while posting.

Zoom – 1

Our first online class is Today!
What we plan to learn:
1) Digestive system
2) Properties of matter

Zoom invite will be sent on this group 5 min before the session. Be ready with writing material.


  1. Be ready 5 min before the session time.
  2. Keep your phone charged.
  3. Keep writing material ready.
  4. Use headphones if you have them
  5. If you have any doubts while the session is going on, write them down and ask them at the end

E-Course – 1

Study the topics Digestion and Properties of Matter from the E-course App (Class 1)

• Do the pan balance activity. Are you able to complete all 3 tasks of balancing?
• Take self notes of all the new things you learn.
• Take the short tests at the end.

Video Lecture – 1

Topic: Force and pressure

  1. Video – Newton’s laws of motion (inertia, action and reaction), gravitation , friction, other forces.

2. Video: Pressure

Try to do the activities and answer the questions given at the end of this video.

Zoom – 2

Topic: Classification of animals

Zoom invite will be sent on this group 5 min before the session.

Questions and Answers

1) What is diffusion?
Random mixing of gas or liquid particles. This happens continuously even without any fan or wind. Example: The smell of agarbatti ignited at one corner spreads everywhere in the room.

2) What is hardness? Give example
Scratches will not come easily. Wear will be less by rubbing. Glass is hard. Diamond is hardest.

4) What is malleability? Which substance is malleable?
Metals are malleable. Means they can be hammered into thin sheets. Eg: gold, silver, iron

5) How to check if presence of starch?
Put tincture iodine. If it becomes black or blue, starch is present

6) What is the role of liver in digestive system?
Liver produces bile. Which digests fats.

7) What is diabetes?
Related to glucose management of the body. In this disease, insulin is not produced (or cells are not able to use it). There is high glucose level in the blood but the cells are not able to get the glucose

Shared Videos

Animal Classification Videos

Octopus escaping through a small hole

Octopus has soft body and no bones. So it can squeeze from a small hole. It is an invertebrate.

Amoeba eats two paramoecium

Sea Anemone

Chameleon changing colours.
Is a chameleon a vertebrate or an invertebrate? How does it eat food? Is it a reptile or an amphibian? What is the difference between them?

Answer: Chameleon is a vertebrate – reptile. It eats with its long and coiled tongue. Difference – Amphibians can breathe on land as well as inside water. Reptiles can only breathe on land.

Activity –

Video Lecture – 2

Changes in the surroundings

Concepts to learn: Physical and chemical changes, exothermic – endothermic changes and other types of changes.

E-Course – 2

Study the topics:
1. Force and Pressure
2. Animal Classification

3. Changes in Surroundings
from the E-Course App

After each Zoom class and Video Lecture, read the same topic from the E-Course app. This will help you to thoroughly understand the topic. Make a note of every new thing you read and understand. Take the short tests at the end.

Special Zoom Lecture – Astronomy

Topic: Astronomy
[Our beautiful universe!, Life of a star, Big bang theory, How all this was discovered]

This lecture is OPEN to ALL. For 6th to 10th std students or anyone interested in the topic!

You can forward the link to your friends who like science.

Animal Classification

  1. Classify into: Unicellular, Multicellular-Invertebrates, Multicellular-Vertebrates:
    Earthworn, Snake, Frog, Butterfly, Amoeba, Bacteria, Shark, Ant, Human, Penguin
  2. Give examples of animals with many legs but not insects
  3. Which vertebrate animal can breathe by moist skin?
  4. Classify: Fish, Bird, Amphibian, Reptile, Mammal –
    Dolphin, Turtle, Frog, Snake, Penguin, Dinosaur, Duck, Tiger, Shark, Whale


  1. Unicellular – Amoeba, Bacteria
    Multicellular-Invertebrates – Earthworn, Butterfly, Ant
    Multicellular-Vertebrates: Snake, Frog, Shark, Human, Penguin
  2. Lobster, crab (10 legs), spider, scorpion (8 legs), millipede, centipede (many legs)
  3. Frog (amphibian) can breathe through moist skin. (Earthworm and Leech can also breathe through moist skin but they are not vertebrates)

  4. Fish – Shark
    Bird – Duck, Penguin
    Amphibian – Frog
    Reptile – Turtle, Snake, Dinosaur
    Mammal – Dolphin, Tiger, Whale

E-Course 1 – Test

Topics: Digestion and Properties of Matter.

  1. Why are we able to swim in the dead sea even without knowing how to swim?
  2. Will the mass of a 20 kg boy be more or less on the moon? Why?
  3. How can glass be hard and brittle at the same time?
  4. The video of which insectivorous plant is shown in the topic ‘digestion’?
  5. Food is able to enter our stomach even if we chew and swallow it in sleeping position. Or even in ‘shirsasan’ (upside down) position. How is this possible?

Zoom – 3

Topic: Metals and non metals

Note: Questions will be asked on Force and pressure and Changes in the surroundings. Please go through the video links sent earlier.

Zoom invite will be sent on this group 5 min before the session.

Shared Videos

Observe the videos –

  1. Soft and Strong (Reactive Metals)
    We have studied about strong (very reactive) metals at our Homibhabha class. Write the names and properties of these metals. Which is the most reactive metal?
  2. Gallium Spoon put in hot tea
    What is the spoon made of? What happens to it?
  3. Liquid bromine reacting with aluminium.
    Is bromine a metal or non-metal?

Metal Samples

Try to identify the samples seen in our zoom class from this photo.


  1. Zinc cube
  2. Aluminium cube
  3. Lead cube
  4. Copper cube
  5. Brass cube (Alloy of copper + zinc)
  6. Brass vessel (same alloy as above)
  7. Mercury in bottle
  8. Fools Gold (Iron pyrite – shines like gold, so many attempts were made to extract gold from it)
  9. Silver (Manohardas Narayandas shuddh chandi 😀) Observe black layer of silver sulphide at the edges.
  10. Soldering wire
  11. Nichrome wire (Nickel + Chromium)

Al and Pb Cubes

We measured the weights of an aluminium cube and a lead cube of same size and shape. You can see the readings in the photo below.

Can you tell which one is the Lead cube – A or B?
(Hint: Look at the weight, not the cube.)

Why is their weight different even if they are of the same size?



  1. Both cubes have same size. That means same volume.
  2. Cube B weighs more (spring balance reading). That means mass is more.

So we can conclude, mass in cube B is more closely packed.
Or Density of cube B is more.

We know that lead is denser(used to make bullets) than aluminum (make aircrafts which can fly.).
So Cube B is lead.
Cube A is aluminium

Respiration and Circulation – Study from App

Go to E-Course – Class 2 – Respiration and Circulation

On page 2 you will find a link to install our separate app (MBook) for this topic. Install it and study from it.

In the next class, we will have a short discussion and question-answer session on this topic. Keep your doubts ready or ask them on whatsapp.

Respiration and Circulation – Activity

Measure your pulse rate = Number of heartbeats in one minute.
Also measure your rate of breathing = How many times you breathe in one minute.

Jump up and down continuously for 1 minute.
Now measure your pulse rate and breathing rate again.

What do you observe? Explain.


Generally rate of heart beats is 72 per minute. But it can vary considerably from person to person.

You would have observed that heartbeats as well as breathing rate increase as you start jumping.
As we do some exercise our cells use up more oxygen from the blood and CO2 level in the blood increases. So to supply more oxygen to the body, our breathing rate and heartbeats increase.

Zoom – 4

Topic: Simple Machines

Zoom invite will be sent on this group 5 min before the session.

Simple Machines

Name and identify the simple machines shown in these images. Make a table with columns as – Name, What is at the centre, Type (as we did in class)

Also identify objects around you that make use of simple machines. If you find 4 or more, you can post a photo with labels.


  1. Wheelbarrow – Lever Type 2
  2. Scissor shaped tongs – Lever Type 1
  3. Coal Tongs – Lever Type 3
  4. Spoon used to open a can lid – Lever Type 1
  5. Pan Balance – Lever Type 1
  6. Bottle Opener – Lever Type 2
  7. Pulley – Not a Lever
  8. Oars for rowing – Lever Type 1
  9. Claw of hammer used to extract a nail – Lever Type 1

Some explanations shown in the images below –

Changes in Surroundings

# Curdling of milk

Take a a few spoonfuls of milk in a container. Squeeze some lemon juice into it. Observe the change.
What gets formed?
Is this a physical or chemical change?
Is this a reversible change?


  1. Proteins (white solid) of the milk gets separated.
  2. This is a chemical change
  3. It is an irreversible change.

# Heating Sugar

Do this in presence of your parents ONLY.

Take some sugar in a spoon with a sufficiently long handle. Heat it on the gas flame. (Parents to ensure the SAFETY). Observe. Do you observe yellowish-brown liquid?

Heat it for some more time. What do you observe?
Is it a physical or chemical change? Explain.

[You can post your photo/video if you have done the activity]

Observe the video – heating of sugar

Zoom – 5


1.Classification of Plants
2. Methods of Separation

Classification of plants

  1. Observe various types of foodgrains, spices, oilseeds, etc used in food preparations in your house. Learn their names. Identify which are monocots and which are dicots.
  2. Classify the following plants:
    First identify if the plant is flowering or non-flowering. If it is flowering, also identify if it is monocot or dicot –
    Cauliflower, Algae, Beetroot, rice, cactus, bamboo, mango, coconut.


Q1. Some plant products you might have found in your house:

Dicots – All Pulses like moong, matki, chawli, green gram, lentil, soyabean, dalchini, clove, oilseeds (groundnut, til, sesame,flax, mustard, cashenut, almond),
Most vegetable plants like cabbage, carrot, tomato, brinjan, bhendi, palak, methi, onion, potato, etc are also dicots.

Monocots – rice, wheat, jowar, ragi, nachni, sugarcane, elaichi, banana, supari (betelnut), maize

Q2. Classify the following plants:

Non flowering plant – Algae

Flowering Plants:
Monocots – rice, bamboo, coconut.
Dicots – Cauliflower, Beetroot, cactus, mango