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Clothes Drying and Evaporation

Clothes dry faster on hot, sunny days.
Windy days also affect the speed of evaporation.
The speed of evaporation depends on:
- Nature of liquid
- Temperature
- Surface area
- Humidity
Sweating cools the body as sanitizer applied to the skin makes one feel cold due to evaporation.
Water cycle processes include evaporation and condensation.

Food, Nutrition, and Health

Good nutrition and dietary habits lead to sound health and mental growth.
Food provides energy, supports growth and development, repairs body parts, protects against diseases, and maintains fitness.
A variety of food is needed because:
- Food contains different kinds of nutrients.
- Not all food items have the same nutrients.
- Different nutrients perform different functions.
Nutrients provide energy, aid growth, and protect against diseases.
Examples of situations where specific foods are needed:
- Marathon runners drink glucose water for quick energy.
- Laddoos are consumed in winters.
- Growing children need pulses, milk, and eggs for growth.
- Fruits, vegetables, and plant-based foods should be included in the daily diet.
Different food items are required for specific body functions and activities.
Need to find out the functions and sources of different nutrients required by the body.

Table 13: Functions and sources of different nutrients

Nutrients:
- Carbohydrates
- Fats
- Proteins
- Vitamins
- Minerals
Water is also a nutrient and is essential for:
- Absorption of nutrients from food.
- Removal of waste through sweat and urine.
Roughage (fiber-rich plant-based foods) aids in easy defecation.
A balanced diet includes all nutrients. Deficiencies in any nutrient can cause health problems.

Activity W2.2 (a): Deficiency Diseases

Case Studies:
- Sailors in earlier times suffered from scurvy due to Vitamin C deficiency, which causes bleeding and swollen gums.
  - James Lind found that lemons and oranges helped sailors recover from scurvy.
- In the 1960s, swelling at the front of the neck (goitre) was observed in individuals in the Himalayan region and Northern plains of India due to iodine deficiency.
  - Consumption of iodised salt reduced the symptoms.

Deficiency Diseases: Causes, Symptoms, and Remedies

Importance of each nutrient in the diet.

Table 14: Common symptoms of deficiency diseases

Deficiency diseases and their symptoms:
- Vitamin A deficiency: Night blindness
- Vitamin C deficiency: Scurvy
- Vitamin D deficiency: Rickets
- Iron deficiency: Anaemia
- Iodine deficiency: Goitre
Discussions on these diseases can improve understanding, critical analysis, and communication skills.

Activity W2.2 (b):

India is an agricultural country with diverse soil and climate types.
Many people are involved in farming practices.
Crops cultivated include vegetables, fruits, oilseeds, and fibres.
Daily food items come from these crops, grown locally or far away.
Questions to consider:
- How does food reach from agricultural farms to local markets and homes?
- What steps are involved in the process?
- How much energy and effort are involved?

Food Miles

Time is required to get food items like chapati, rice, and vegetables from the farm to the plate.
Understanding the steps involved from wheat seed germination to making chapati.
The entire distance travelled by a food item from producer to consumer is its food miles.
Food miles affect the cost of food items.
Correlate food costs with human effort, energy, and distance travelled.
Reducing food miles can cut costs and pollution.
Eating locally grown food supports local farmers, reduces pollution, and provides fresher, healthier food.

Activity W2.3: Prepare Your Own Food Miles

Make the food miles of:
- Rice/pulses
- Any vegetable
- Any fruit
Create a pictorial flowchart of the story of ‘Farm to Plate’ for each food item.
Find the timeline for the various processes involved.
Discuss the energy, time, and human resources involved.
Questions to consider:
- Why is food getting costlier?
- How much cost is put in a field to make a one-time meal?
Ways to reduce food miles, save energy, and protect the planet.

Activity W2.4: Know Your Millet

Millets are small-sized grains, an integral part of the Indian diet for centuries.
Interact with elderly persons to learn about millets and their benefits.
Benefits of millets:
- Rich in vitamins, minerals, and dietary fibres.
- Help keep us healthy, protect us from diseases, and support body functions.
Questions to explore:
- Can millets help overcome nutritional deficiencies?
- How is millet cultivation helpful for farmers?
- Can millets be grown in adverse climatic conditions?

Activity W2.4 (a): Variety of Millets Around Us

Several types of millets are grown in India, known differently in different languages.

Table 15: Millets and local names

Examples of millets:
- Pearl Millet (Bajra)
- Sorghum Millet (Jowar)
- Finger Millet (Ragi)
- Foxtail Millet (Kakum)
- Barnyard Millet
- Little Millet
- Proso Millet
Add more kinds of millets and their local names in different languages.
Find out which is the most widely grown in India.
Mapping of different Indian varieties of millets.

Extended activities

Plant millet seeds in the school garden.
Collate traditional millet recipes from different regions of India.
Create awareness about the benefits of millet consumption by organising a millet fair in school.
Plan a field trip to local farms or millet processing units to gain hands-on experience about millet cultivation.

Seed Germination

Sprouted pulses are examples of germinated seeds.
Seed germination: The process by which a seed develops into a seedling and eventually into a plant.

How Seeds Germinate

Conditions seeds require for proper germination.

Activity 2.5 (a): Effects of Environmental Factors on Seed Germination

Take four identical pots (A-D) filled with the same garden soil.
Sow 4-5 healthy bean seeds in each pot.
Keep each pot in different environmental conditions for ~15 days.
- Pot A: Direct sunlight and dry soil
- Pot B: Direct sunlight and excess water
- Pot C: Dark location and moist soil with moderate water
- Pot D: Direct sunlight and moist soil with moderate water

Table 16: Effect of environmental conditions on seed germination

Record predictions about seed germination in each pot.
Observe the pots each day, maintaining water and light conditions.
Record observations in Table 16.
Match observations with predictions.
Discuss results with peers.
Conduct the activity with other seeds to see if conditions are the same for every type of seed.
What happens in the absence of one or more of these conditions?
Discuss scientific explanations of seed germination in the presence/absence of essential requirements.
Questions:
- Why do we soak seeds for sprouting? How does water help?
- Do seeds require air? What happens if the soil is waterlogged?
- Is sunlight essential? Is there any other factor affecting seed germination?

Natural Resources

Earth is the only planet known to support life.
Life depends on temperature, air, water, food, etc.
Resources available on Earth and energy from the Sun are necessary for life.
Abundant resources are natural resources (e.g., sunlight, fruits, vegetables, air, water, land, rivers, coal, petroleum).
Humans have also created resources using natural resources (e.g., electricity, buildings, furniture).

1. What are Natural Resources?

Natural resources are things needed from the natural world for existence.
Examples: light from the Sun, air from the atmosphere, water from rivers, food from plants and animals.
Wise usage of natural resources has been acknowledged by ancient civilizations.
Classification of resources:
- Depletable (limited quantities): Coal, minerals, petroleum, natural gas.
- Non-depletable (replenish themselves): Light from the Sun, wind, tidal energy.
Energy from non-depletable resources can be used for mankind.

Activity W3.1(a)

Classify the following resources as Non-depletable (Renewable) and Depletable (Non-renewable).

Table 17

Resources to Classify:
- Coal
- Solar energy
- Wind energy
- Oil
- Water
- Air
- Uranium
- Biomass
- Natural gas

2. The Management of Natural Resources

It is crucial to use natural resources wisely for future generations.
Important methods to manage natural resources:

2.1 Soil Conservation

'Fallowing' (leaving fields uncultivated) and 'crop rotation' are key sustainable practices.
Organic fertilizers like compost and cow dung were used in ancient agricultural practices.
Modern methods aim to increase productivity, efficiency, and sustainability by improving soil fertility, using genetically modified crops, drip irrigation, sprinkler systems, pest management, and organic farming.
Use of tractors, combine harvesters, seed drills, and plows.

2.2 Water Conservation

India's traditional methods of conserving water serve as examples.
Rainwater harvesting is a crucial technique:
- Step wells, kunds, bawadi, tanka and johad systems.
- Step wells (Baolis) are structures built to harvest and store water, especially in dry regions.
- Kunds are small circular tanks common in arid regions.
- Tanka is an old rain water harvesting structure in different shapes and sizes.
- Johads (pokhars or percolation ponds) are traditional, community-owned wetland areas.
Efficient and sustainable water resource management ensures water availability during dry seasons.
Water bodies have long been seen as essential to the environment.
People offer prayers and ceremonies to rivers (like the Ganga) in appreciation.

Solar Oven

A solar oven or cooker cooks food by trapping sunlight.
Components:
- Aluminum foil as reflectors.
- Cardboard box as cooking chamber.
- Transparent plastic foil to allow sunlight in but prevent heat from escaping.
- Black paper sheet for heat absorption.
Instructions to prepare a solar oven:
- Step 1: Cut a flap on the top of a cardboard container, leaving a few centimetres around the sides.
- Step 2: Affix sheets of black paper inside the cardboard box.
- Step 3: Affix the aluminum foil on the interior of the lid and the edges.
- Step 4: Cover the top with a clear plastic foil.
- Step 5: Place a bowl (containing some water and rice in it) inside the box.
- Step 6: Leave the solar oven in the Sun for about 2 hours.
- Step 7: Check if the rice has cooked.

Activity W3.1 (c): List Different Methods of Conservation of Natural Resources in Your Locality.

Metals and Non-metals: Physical Properties

Activity W3.2

Familiar with materials like iron, aluminum, copper, etc.

Table 18: Appearance and Hardness of Materials

Materials: Iron, Coal, Sulphur, Aluminum, Copper.
- Appearance (Shiny/Dull)
- Hardness (Very Hard/Not Very Hard)
Metals can be distinguished from non-metals based on physical and chemical properties.

Activity W3.2 (a): Metallic Lustre

Take samples of iron, copper, aluminum, coal, and sulphur.
Note the appearance of each sample.
Clean the surface of each sample by rubbing with sandpaper and note their appearance again.

Table 19

Sample:
- Iron nail
- Coal piece
- Aluminium wire
- Pencil lead
Appearance of sample before and after rubbing by sandpaper.
Metals in their pure state have a shining surface, called metallic lustre.
Iron, copper, and aluminum show metallic lustre, thus they are metals.
Coal does not show metallic lustre, thus it is a non-metal.
Do not be confused into thinking that all materials with shining surfaces are metals and others are non-metals. This concept is only applicable to materials that are elements.

Activity W3.2 (b): Hardness

Take small pieces of iron, copper, and aluminum.
Try to cut these samples with a sharp knife and note observations.
Repeat the activity with coal, sulphur, and iodine.
Metals are generally hard, but hardness varies.
Non-metals are easy to cut with a knife.
Iron, copper, and aluminum are metals, and coal, sulphur, and iodine are non-metals based on hardness.
Mercury is a liquid metal. Sodium and potassium metals are soft and can be cut by a knife.

Activity W3.3 (c): Malleability

Take an iron nail, a coal piece, a piece of thick aluminum wire, and a pencil lead.
Beat the iron nail with a hammer (take care not to hurt yourself).
Hit the aluminum wire hard with a hammer.
Repeat the treatment on the piece of coal and lump of Sulphur.

Table 20

Object/Material:
- Iron nail
- Coal piece
- Aluminum wire
- Lump of sulphur
Change in Shape Material (Flattens/ Breaks into Pieces)
The shape of iron nail and aluminum wire changes on beating.
Metals can be beaten into thin sheets, which is called malleability.
Coal and sulphur do not show this property, thus they are non-metals.

Activity W3.2 (d): Ductility

Aluminum and copper wires are commonly used.
The property of metal by which it can be drawn into wires is called ductility.
Gold is the most ductile metal.
A wire of about 2 km in length can be drawn from one gram of gold.

Activity W3.2 (e): Sonorous Sound

Notice the difference in sound when dropping an iron sheet/plate, a metal coin, and a piece of coal on the floor.
Metals produce a ringing sound when struck hard, called sonorous.
Non-metals like coal and sulphur are not sonorous.

Activity W3.2 (f): Thermal Conductivity

Take an aluminum or copper wire.
Clamp this wire on a stand.
Fix a pin to the free end of the wire using wax.
Heat the wire with a spirit lamp/Bunsen burner, candle near where it is clamped.
Metals are good conductors of heat.
Non-metals are poor conductors of heat.

Activity W3.2 (g): Electrical Conductivity

Set up an electric circuit.
Place the sample (iron nail, copper wire, aluminum foil, coal, and sulphur) to be tested in the circuit between terminals A and B.
Does the bulb glow?

Table 21: Observation table for electrical conductivity

Sample:
- Iron Nail
- Copper wire
- Aluminum foil
- Coal
- Sulphur
Does the bulb glow? (Yes/No)
Metals are good conductors of electricity, while non-metals are poor conductors of electricity.
Iron, copper, and aluminum are metals, while coal and sulphur are non-metals.
Elements that are hard, lustrous, malleable, ductile, sonorous, and good conductors of heat and electricity are called metals.
Examples of metals are iron, copper, aluminum, calcium, magnesium, etc.
Elements that are soft and dull, break down into a powdery mass when tapped, are not sonorous, and are poor conductors of heat and electricity are called non-metals.
Examples of non-metals are sulphur, carbon, oxygen, phosphorus, etc.

Chemical Properties of Metals and Non-metals

Activity W3.3: Chemical Properties of Metals and Non-metals

Activity W3.3 (a): Reaction with Oxygen

Familiar with the phenomenon of rusting of iron and burning a magnesium ribbon in air.
Oxide formation takes place in both processes.
Complete the following reactions of iron and magnesium with oxygen:
- Iron + Oxygen + Water → ?
- Magnesium + Oxygen → ?
Check the nature of rust formed:
- Collect a spoonful of rust powder and dissolve it in very little water.
- Shake the suspension well.
- Test the solution with red and blue litmus papers.
Is the solution acidic or basic?
Recall the activity of burning a piece of magnesium ribbon.
Dissolve the ash obtained on burning the magnesium ribbon in warm water and test for its acidic/basic nature.
The red litmus turns blue, so magnesium oxide is basic in nature.
In general, metallic oxides are basic in nature.
Reaction of non-metals with oxygen (demonstrated by the teacher):
- Take a small amount of powdered sulphur in a deflagrating spoon and heat it.
- As soon as sulphur starts burning, introduce the spoon into a gas jar/glass tumbler, and cover the tumbler with a lid.
- Remove the spoon after some time. Add a small quantity of water into the tumbler and quickly replace the lid. Shake the tumbler well.
- Check the solution with red and blue litmus papers.
The product formed in the reaction of sulphur and oxygen is sulphur dioxide gas.
When sulphur dioxide is dissolved in water, sulphurous acid is formed.
- Sulphur dioxide + Water → Sulphurous acid
Sulphurous acid turns blue litmus paper red. Generally, oxides of non-metals are acidic.

Activity W3.3 (b): Reaction with Water

Water reacts differently with different metals depending on their reactivity.
Highly reactive metals like sodium and potassium react violently with water, resulting into explosion.

Activity W3.4: Rusting of Iron

Rusting is a slow chemical change when iron reacts with water and oxygen, forming iron oxide.
The process is called oxidation and occurs when iron is exposed to moisture for a long time.
Scientists experiment by placing iron nails in different conditions (dry air, water, salty water).
Rust forms faster in water and quicker in salty water, proving both oxygen and water are needed for rusting.
Preventing rust requires keeping iron dry or using coatings like paint or oil.

Procedure

Take an iron nail and apply grease or oil to its surface.
Place the second iron nail inside a sealed plastic bag.
Wrap the third iron nail in a wet cotton cloth and place it in a sealed plastic bag.
Observe all the nails after 2-3 days.

Chemical Reaction

Iron + Oxygen + Water → Iron Oxide (Rust)

Heat and Air

Activity W4.1: Let Us Investigate

Take two paper cups of equal size.
Hang them using threads of equal length in an inverted position on the two ends of a wooden stick.
Hold the thread, such that the wooden stick is horizontal.
Place a burning candle below one of the cups.

Activity W4.1 (a, b): Hot air rising up

Cup with the candle rises up because the air surrounding the candle flame heats up.
Warm air expands, becomes less dense, and rises up.
The smoke from incense sticks and firewood rises up due to warm air.
Two points:
- When air is heated, it expands and rises up.
- The smoke from a downward-pointing incense stick will move upwards.

Water Cycle

Water in oceans, rivers, lakes gets heated and transformed into water vapour.
Plants release water as vapour through transpiration.
Moist air is warm and light, expands, and rises up.
At higher altitudes, moist air cools down and condenses into water droplets.
Droplets merge, become heavy, and fall as rain, snow, or hail (precipitation).
Rain water and melted snow flow back into rivers and oceans.
A small part seeps into the ground and is stored as groundwater (infiltration).
Whatever water was lost as vapour comes back in the form of rain, snow, or hail.
Two important points:
- The total water content of the planet earth is conserved in this process.
- By redistributing water over different regions, it helps in maintaining the life on the earth.

Understanding Adolescence and Puberty

Activity W4.2: Adolescence

Adolescence: The transition phase between childhood and adulthood.
Adolescents are also called teenagers.

Activity W4.3: Understanding Puberty

The beginning of changes that lead to sexual maturity.
Physical changes include: increase in height, breast development and menstruation in girls, deeper voice in boys, pimples on face, etc.
Summarise the points raised in the Table 23.

Table 24: Pubertal changes that are specific and common in males and females

Categorise observations that occur only in males, only in females, and those common to both.
Measure the height of each student and note observations in Table 25.

Table 25: Height measurement and analysis in a group of students

Details to Fill:
- Maximum height
- Minimum height
- Average height
- Difference between the average height of boys and girls
Analyse the data and make a graph between age (x-axis) and height (y-axis) of the students.
Try to explain that gender changes occur because of scientific phenomenon related to hormonal and physical growth and development.

4.4 Behavioural Changes in Adolescents

Adolescents undergo emotional, attitudinal, and behavioural changes.
Seek help from elders if needed.

Activity W4.4 (a): Understanding the Behavioural Changes in Adolescents

Fill the responses (Tick Mark) and analyse the findings.

Table 26

Parameters:
Strongly Agree/Agree/Disagree/No Such Observation

Do you feel more emotional and often have mood swings?
Do you become easily upset?
Do you think that you are now a grown up and want to make your own decisions?
Are you concerned about the changes in your body appearance?
Do you feel distracted and easily influenced by peers?
Have you become more confident and aware?
Have you developed any changes in your likings?
Do you feel that your attitude has changed towards yourself and also towards the opposite sex?
Calculate the percentage of students opting for each of these parameters.

4.5 Reproductive Health

Includes physical, mental, and social well-being in relation to the reproductive system.
Build positive relationships with family and friends.
A healthy mind helps in realising one's worth and coping up with stressful situations.

4.6 Taking Care of Health During Adolescence

Make a list of things needed to be healthy and live a happy and stress-free life during adolescence.
Discuss the following:
- What is the ideal diet for the healthy growth of adolescents? Which nutrients should be included?
- Why is it important to take care of personal hygiene during puberty?
- How do physical activities help in the healthy growth of adolescents?
- What is menstruation in girls and why is it of utmost importance for girls to understand the phenomenon?
- How can boys support female peers during periods, become empathetic and break the stigma associated with it?
Debate on these topics in the class.
Discuss the myths and taboos:
- Myths to Discuss and Justify with Scientific Explanation:
  1. Should not be allowed to work in the kitchen.
  2. Should stay in a separate room during her menstrual cycle.
  3. Should not touch and eat pickles.
  4. Should not wash hair during menstruation, etc.
Work in pairs or small groups and create posters with the aim of spreading awareness.
- Posters Content:
  - Slogans and visuals promoting menstrual hygiene and breaking stigma.
  - Menstrual cycle education for everyone.
  - Myths and facts about menstruation.

Stars and Constellations

Some stars are bright, and others are dim. Stars shine with their own light.
Groups of stars form patterns like shapes of familiar things, called constellations.
Recognizing stars and their patterns was useful for navigation.
The term constellation is commonly used for these groups of stars.

Activity W5.1: Night Sky Watching and Stargazing

If it is a clear cloudless night, a large number of stars may be visible in the sky.
In big cities, the sky may be rarely clear, and only a few stars are seen due to light pollution.
Night sky is best viewed from open dark areas.

Preparation for Night Sky Watching:

Identify a dark open area away from lights, tall buildings, and trees.
Choose a date and time based upon what you plan to identify.
Choose a moonless night (Amavasya) with no clouds, particularly for the Pole Star.
Access a mobile app with a sky map or print out images of the constellations you plan to view.
Carry a magnetic compass to find directions and a notebook to note or draw your observations.
Wait for about half an hour for your eyes to get adjusted to the darkness.
Observe and identify the pattern formed by the stars at night using the chart.
Gather information about the constellation as listed in the Table 27.
Compare the data with others in the following class.

Comparison Chart:

Constellation
Table Content:
- Name of the Constellation
- Shape of the Constellation
- Brightest Star
- Faintest Star

Activity W5.1 (a): Try to Locate Orion, Big Dipper in the Night Sky

Look for the Big Dipper during summer in the early part of the night.
Locate the Pole Star using the two stars at the end of the Big Dipper's cup.
Orion is best viewed from December to April after sunset.
Three bright stars in a short, straight line are around the middle of Orion (the belt of a hunter).
Locate the very bright star Sirius close to Orion by tracing a line through the three middle stars of Orion towards the east.

Activity W5.2: Virtual Navigation with Stellarium App

Material Required: Stellarium app

Guide students to use Stellarium to locate the Big Dipper and trace its path to the Pole Star.
Explore how the visibility and position of the Pole Star change based on the geographical location (for example, equator vs. northern hemisphere).
Students interactively explore surrounding constellations, identifying their patterns.
Students experiment with Stellarium's time settings to observe seasonal changes of stars in the sky.

Constellations

Two distinct patterns of stars, the Big Dipper and the Little Dipper.
The Pole Star or Polaris is a part of the Little Dipper.
The Pole Star appears stationary in the North direction.
The Big Dipper lies in the constellation Ursa Major, while the Little Dipper lies in the constellation Ursa Minor.
In India, the Big Dipper is known as Saptarishi, and the Pole Star is known as Dhruva tārā.

Galaxy

Includes interstellar gas, dust, dark matter, stars and stellar remains.
The Milky Way Galaxy (Ākāśha Gangā) includes the Solar System and has billions of stars.
Stars are bound in the galaxy due to gravity.
In the absence of gravity, everything would shoot off into space.

Activity W5.3: The Solar System

Key Concepts

The Sun is the closest star and the center of the Solar System, providing energy to all life on Earth.
The eight Planets - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune revolve around the Sun.
Natural satellites orbit planets. The moon is the natural satellite of the Earth.
Objects that move around planets are called satellites. Moons are natural satellites. The Earth has one Moon, while Mars has two moons. Jupiter, Saturn, Uranus and Neptune each have a large number of moons.

Activity W5.4: Build a Model of the Solar System

Material Required: Balls of varying sizes, string, paint and cardboard

Divide students into groups, assigning each group a planet or celestial body to research and model.
Students create labeled models of their assigned planets, moons, or other celestial objects, ensuring relative sizes and distances.
Assemble the Solar System in the classroom or outdoors, using string to represent orbits.
Each group presents the features of the object they have been asked to model, sharing interesting facts about their object (for example, surface features, atmosphere and rotation).

Motion of the Earth

The earth has two types of motions, namely revolution and rotation.

Two Main Types of Motion

Revolution: The Earth revolves around the Sun in an orbit. This motion takes about $365.25$ days to complete, which defines a year.
Rotation: The Earth rotates around its own axis, an imaginary line that runs from the North Pole to the South Pole. This rotation causes day and night. One full rotation takes approximately $24$ hours.

Simulation: Day and Night

The earth receives light from the sun. Due to the spherical shape of the earth, only half of it gets light from the sun at any time.
The portion facing the sun experiences day, while the other half away from the Sun experiences night.

Activity W6.1: Earth's Rotation and Day-Night Simulation

Objective: To help students understand the rotation of the Earth and occurrence of day and night due to it.
Material Required: A globe or a large ball (such as basketball, football) representing the earth, a torch or a table lamp (to represent the Sun), a room/hall with dim light, small sticky notes or markers.

Arrangement for Showing the Occurrence of Day and Night

Procedure

Set Up the Model:
- Mark two diagonally opposite points on the big ball representing the poles of the earth. Insert a knitting needle through these points. This will represent the axis of the earth.
- Place the torch or lamp in the centre of the room. This will represent the Sun.
- Position the big ball a few metres away from the lamp. The ball will represent the Earth. Ensure that the ball's axis is tilted by about $23.5$ ° to mimic the Earth's tilt.
Mark a Location:
- Stick a small note or put a mark using a marker on the ball to represent your location on the Earth (for example, India).
Simulating Day and Night:
- Turn off the room lights, leaving only the flashlight or lamp on.
- Slowly rotate the ball counter-clockwise (when viewed from above the North Pole) to simulate the Earth's rotation. Remember that the Earth rotates from west to east.
- Observe how the mark moves into the lighted area (day) and then into the dark area (night). Note the direction from which the light appears falling on the mark.
Observation and Discussion:
- Have students observe how only half of the ball is illuminated at any time, while the other half remains dark.
- Ask them to notice how the marker moves between the light and dark areas, creating the day-night cycle.

Questions

Why does the Sun seem to rise in the east and set in the west?
If the Earth's rotation were faster, how would the length of a day change?
What might happen if the Earth did not rotate at all?

Activity W6.2: Solar and Lunar Eclipses

A solar eclipse occurs when the shadow of the Moon falls on the Earth.
A lunar eclipse occurs when the Sun, the Earth and the Moon are in line so that the shadow of the Earth falls upon the Moon.

Setup for Demonstrating Solar and Lunar Eclipses

Through the following activity, we can understand the phenomenon of eclipse.
Solar and Lunar Eclipses
Material Required: Torch (to represent the Sun), 2 plastic balls one smaller than the other, 2 tea paper cups and dark room or dim lighting for better visibility of the effects.

Steps to Model Solar and Lunar Eclipses

For Solar Eclipse

Set up the torch: Position the torch on one side of the setup to act as the Sun. Make sure the torch is steady and positioned, so that it casts light in the direction of the plastic balls.
Position the Earth: Place the larger plastic ball in the middle to represent Earth. You can mount it using a tea paper cup to keep it stable. The Earth should be fixed in place, as it will not move