Candle and Agarbatti
What happens when air is blown on burning candle? Explain.
The candle gets extinguished. This happens because the air we blow cools down the wick and its temperature drops below ignition point of wax.
What happens when air is blown on agarbatti? Can you give a similar example?
Agarbatti burns brightly (bright orange colour). Similar example is burning of coal. Coal burns brightly when air is blown.
Try at Home
Do this in presence of your parents.
• Take some wax in a spoon. Heat the spoon on candle. Observe carefully.
• Keep the spoon aside and let it cool down.
• Extinguish the candle. Observe the wax in the spoon.
• Observe the back side of the spoon.
Q. What do you observe?
Q. Which change happened in the wax?
Funnel on Bottle
1. Does the water enter the bottle when the funnel is pressed down tightly? Why?
When the funnel is pressed tightly, water does not enter the bottle.
Reason: The air inside the bottle occupies the space inside the bottle. As funnel is pressed tightly, this air cannot come out. So there is no space for more water to enter.
2. Does the water enter the bottle when the funnel is lifted up? Why?
When the funnel is lifted, water enters the bottle.
Reason: The air inside the bottle can now come out and create space for the water to enter.
3. Do gases have fixed mass?
Yes. Gases have fixed mass.
4. Do gases have fixed volume?
No. Gases do not have fixed volume.
5. Do gases have inertia?
Yes. Gases do have inertia.
6. If a small hole is drilled in the upper part of the bottle, and the funnel is held tightly, will the water enter into the bottle?
If a small hole is drilled, water will enter into the bottle. Because the inside air can come out through the hole and allow the water to enter.
Cylinder and Tape
Area of paper = Circumference x Height = 24.6 cm x 9.6 cm = 236.16 sq cm
Spoon used to open the lid is acting as 1st type of lever.
Turmeric Test
- What can we say about the nature of A and B?
Turmeric remained yellow in A. So, A is Acidic or Neutral
Turmeric turned red in B. So B is Basic.
2. Give 2 examples of neutral solutions
Salt Solution, Sugar Solution
3. Name any 2 acidic substances we eat.
Vinegar, tomato, lemon, orange
Mass of Mixture
A mixture of chemicals is kept in a container on a weighing scale. Water is added
1.Write your observations. 2.What can you infer from this? Explain.
Identify Salt water and Normal Water
Q1. Which sample contains salt water?
Sample A contains salt water.
Q2. Explain how you have concluded this.
Object floats in A. So density of sample A is more than density of the object.
Object sinks in B. So density of sample B is less than density of the object.
Since density of salt water is more than that of normal water, Sample A must be salt water.
Q3. Put an amla in salt water and normal water and observe. What can you say about the density of the amla?
Density of the amla is more than density of normal water but less than the density of salt water.
Good and Bad Conductors
| GOOD Conductors | BAD Conductors |
| A – green wire | C – blue piece |
| B – Yellow wire | D – magnet |
| F – Medicine strip | E – plastic piece |
| G – Safety pin | H – White L shape |
| I – Aluminium L shape | K – Wooden piece |
| J – Metal Screw | |
| L – One rupee coin | |
| M – Ten rupee coin | |
| N – Blue wire | O – Blue wire |
| P – Copper wire | Q – Paper clip |
| R – Brass piece | |
| S – Pencil |
Q 2. Resistance is measured in Ohm
Q 3. When we say current is flowing, actually electrons flow through the circuit.
Q 4. Why is the pencil a good conductor?
The graphite rod inside it is a good conductor of electricity.
Q5. Magnesium strip (wire) is a good conductor.
Glucose in water
1.Measure and note the initial temperature of water = 29o
2.Add glucose powder and stir slightly.
Measure and note the new temperature of the mixture = 27o
3. What change in temperature did you observe?
Temperature decreased by 2 degrees.
4. Which type of change is this?
Endothermic Change
5. Tell one more change of this type.
Urea + Water
Soap Bubbles
• Bubbles through circular wire are spherical in shape.
• Bubbles through square wire are spherical in shape.
• Bubbles through triangular wire are spherical in shape.
* (for 9th Std) Why does the shape of the bubbles remain the same?
Because of surface tension, the surface film of the bubble always tries to take lesser surface area. For any fixed volume, sphere shape always has minimum surface area.
Iodine Test
| Sample | Colour After adding Tincture iodine | Conclusion |
| 1 | Black / dark blue | Starch is Present |
| 2 | Black / dark blue | Starch is Present |
| 3 | Yellow | Starch is Absent |
| 4 | Yellow | Starch is Absent |
Q2. How are you able to conclude?
Iodine test: if tincture iodine gives blue or black colour, starch is present.
Q3. Carbohydrates contain which elements?
Carbohydrates contain Carbon, hydrogen, oxygen
Q4. Is sugar a carbohydrate? Can we detect sugar with iodine test?
Sugar is a carbohydrate. But not starch. So we cannot detect it with iodine test.
Q5. What is starch?
Starch is a very long chain of carbohydrates (glucose) molecules.
Q6. Tincture iodine is iodine dissolved in alcohol.
Density of Aluminium Cubes
| Cube size | Length | Volume | Mass | Density |
| Small | 1 cm | 1 cc | 2.6 gm | 2.6 gm/cc |
| Medium | 1.9 cm | 6.859 cc | 18.2 gm | 2.65 gm/cc |
| Large | 2.6 cm | 17.576 cc | 45.6 gm | 2.59 gm/cc |
1.Write the formula for volume of a cube.
Volume of cube = (length of side)3
2.Write the formula for density.
Density = Mass / Volume
3.What can you conclude from the above experiment?
Density remained same for all sizes.
Density is a property of the material.
It does not depend upon volume / size / shape.
Biology – Identify and find the odd one out
1.Identify the samples.
Crocodile, chameleon, dinosaur, Lizard, frog, Snake, tortoise
2.Find the odd one out with reason.
Odd one out – Frog.
It is amphibian, others are reptiles.
3.Dinosaurs were which type of animals?
Reptiles
Identify the samples
- Starfish
- Coral
- Pila (Shells)
Common Property – All are multicellular invertebrates
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