Maham Masood Sadiq. Ahmed Waqas Zubairi. Supervisor: Dr. Muhammad Sabieh Anwar

Transcription

1 EXPERIMENTS ON WEATHER CHANGE Maham Masood Sadiq Ahmed Waqas Zubairi Supervisor: Dr. Muhammad Sabieh Anwar

2 EXPERIMENT-1 (INTENSITY OF SUN RAYS) 1. Balloon 2. Black Marker 3. Torch 1. Blow up a balloon 2. Mark a line with the help of a black marker along the center of the balloon. The balloon represents the Earth while the line represents the Equator 3. Hold a torch perpendicular to the balloon s equator 4. Move the torch vertically upwards without changing its horizontal distance from the balloon 5. Notice how the bright spot spreads out as the torch moves upwards The spreading of the light shows how the light intensity decreases as we move away from the equator. The Sun acts in a similar manner on the Earth. The Equator receives the highest intensity of its rays all year round while the North and the South poles receive very less sunlight and are hence, the coldest regions on the planet.

3 EXPERIMENT-2 CLOUDS AND FOG 1 Glass Jar Warm water Black Chart paper Scotch Tape Small Shopping bag Match Stick 1. Take glass jar and tape black chart paper on to its one side. 2. Fill 1/3 rd of the jar with warm water 3. Light a match stick, blow it off and throw it into the water once smoke starts coming from it. 4. Immediately place a shopping bag full of ice on the mouth of the jar to seal it. 5. The condensation of the rising water vapors on to the smoke near the ice bag forms a cloud on the upper half of the jar. The smoke enables us to see the condensing water vapors. Clouds are formed in the atmosphere when the water vapor condenses at high altitudes on microscopic particles such as dust or smoke. If a similar condensation takes place on the ground level in winters then fog is formed.

4 EXPERIMENT-3 WEATHER FRONTS 1 Large Glass Jar Jug Hot Water Cold Water Food Coloring Thermometer 1. Take a glass jar and fill 3/4 th of it with cold water. 2. Now fill a jug with hot water and add food coloring to it 3. Slightly tilt the glass jar and slowly pour the colored hot water into it. Make sure the colored water stays near the surface. 4. Straighten the glass jar, you will observe that the colored warm water will lie above the cold water as lighter layer 5. Use a thermometer to measure the difference between the cold and the hot water. The experiment shows that the boundary between the cold and the warm colored water in the jar shows a weather front. In weather patterns, when warm air meets with cold air, the warm air rises above the cold air, condenses and forms clouds which lead to rain.

5 EXPERIMENT -4 CREATING A BREEZE 2 heat proof trays Sand Ice (ا Incense Stick ( Match Stick Heat Proof Mat 1. Take two heat proof trays, fill one with sand and place it in the oven to heat it up 2. Fill the second tray with ice and place both the trays next to each other on a heatproof mat. 3. Take a wooden chip and light it with a matchstick. 4. Place the chip in between the two trays and blow it away. 5. The smoke from the wood will move towards the hot sand plate as air above the ice is dense. The experiment shows how warm air moves away from a high-pressure zone such as the dense air above the ice to a low-pressure zone like the air above the hot sand. This phenomenon gives rise to the land and sea breeze on coastal areas.

6 EXPERIMENT-5 INVISIBLE WATER Large Glass jar Cold Water Bowl with a curved base Warm metal plate 1. Take a glass and fill it with cold water up till 2 inches. 2. Place a jar on a slightly warm place like a mildly hot metal tray. 3. Place a bowl in a fridge until it is cold. Then place it on the mouth of the jar ensuring it is fully sealed. 4. After some time you will observe droplets of water on the base of the bowl. These are caused by the condensation of evaporating water from the hot water in the jar. The experiment shows that when water gets hot and starts to evaporate, it is not visible to us. The air around us contains this invisible water as water vapors that play an important role in the formation of clouds and are the cause of humidity in our environment.

7 EXPERIMENT-6 EXPANDING AIR 1 small 250ml Plastic bottle Pebbles Cold and boiling water Food Coloring Children s play dough or flour dough Drinking Straw Safety Pin Large Jug 1. Take a small plastic bottle and fill 1/3 rd of it with pebbles 2. Now half fill it with cold water and add food coloring to it 3. Place a straw inside the bottle and make sure it is fully immersed into the water 4. Seal the opening of the bottle and the straw with play dough to make bottle airtight 5. Make a tiny whole with the help of a pin in the opening of the straw 6. Fill a jug with boiling water and place the bottle inside it. Ensure that the water comes up till the neck of the bottle. 7. The hot water will cause the pin on the straw to fly away and colored water will come out. The heat from the boiling water in the jug made the air inside the bottle to expand and push the colored water out of the straw. The heat from the Sun similarly causes the air on the Earth to expand and rise. This movement of air forms clouds and thus causes various weather changes around us.

8 EXPERIMENT-7 RISING WARM AIR Cold and Hot water Food Coloring Small tea cup Glass Jar Cling film Rubber band Knife 1. Take a teacup and fill it with hot water. 2. Add food coloring to the water and cover the cup with cling film. Wrap it with a rubber band to ensure it is sealed. 3. Take a clear glass jar and place the cup inside it 4. Now fill the jug with cold water 5. Cut the cling film from the center with a knife to form a hole 6. You will observe that a thin line of colored water will rise up in the jar and spread out at the top 7. The colored water will then gradually cool and spread in the bottle. This experiment once again proved that warm air rises and generates air currents on our planet.

9 EXPERIMENT-8 THUNDERSTORMS 1. Rubber Glove 2. Artificial fiber cloth 3. Metal Plate/Tray 4. Scissors with plastic handle 5. Stopwatch 1. Put on the rubber glove on your hand and lay a cloth on the table. 2. Rub the metal plate on the cloth for 6 minutes until the static charge is gathered on it. 3. Switch off the lights of your room and slowly lower the tip of your scissors on the plate. 4. The moment the scissors touch the plate, a spark will produce between the plate and the tips of scissor and you may hear a faint sound of thunder. The experiment simulates the lightning formed during thunderstorms due to a difference in voltage between the ground and the clouds. The charged plate acts as the highly charged up clouds and when an uncharged conducting scissors approaches the plate, a spark is produced to meet up the voltage gap. This is exactly what happens during a real time thunderstorm.

10 EXPERIMENT-9 MEASURING RAINFALL liter Clear Plastic Bottle 2. Colored Scotch Tape 3. Pebbles 4. Scissors 5. Ruler 6. Water 1. Make a straight cut through the bottle from the point the curved part ends 2. Add some pebbles to the bottle 3. Stick the colored tape above the point from where the pebbles end 4. Add water to the bottle until it reaches top of the tape 5. Turn the top section of the bottle up-side down and fit it inside the bottle 6. Put the bottle outside when it is raining. Measure the water level with the help of a ruler above the tape in centimeters once it stops raining 7. The measured height is the amount of rainfall received by the area What you just made out of the bottle is called a rain gauge and is used to measure the amount of the rainfall received by a city or a town. The standard units for measuring rainfall are centimeters.

11 EXPERIMENT-10 WINTER FROST 1 Glass Crushed Ice Salt 1. Fill a glass with crushed ice and add salt to it. The salt aids in the melting of the ice. 2. Leave the glass at room temperature for a while and you will observe ice crystals on the outside of the glass. They have been caused by the chilling of the water vapors in the surrounding air of the glass. The crystals outside the glass depict the frost seen in winters on cars, plants, roads and windows. The low temperatures cause the water vapors to solidify into ice.

12 Experiment 11 Measuring Air Pressure Bowl/Beaker Large Balloon Scissors Scotch Tape 2 Drinking Straws A4 Colored Card Black Marker Ruler 1. Cut the neck of a balloon and place it over bowl. Fix it over the bowl with the help of a scotch tape. 2. Join the 2 straws together with a tape and stick it on the center of the bowl, above the balloon. 3. Fold the colored card and horizontal lines on it, 6mm apart to make an air pressure scale. 4. Place the bowl on a table and put the card next to the ending of the straw. 5. If the room pressure goes up, the pointer straw would move up the scale and vice versa. The device that you just made is called a barometer and is used to measure air pressure. If the room pressure increases, the balloon is pushed down which causes the straw to move up and an increase in the scale reading where as if the pressure decreases, the balloon inflates and causes the straw to move down the scale. Barometers play an important role in weather forecasting since low pressure causes the rising warm air to carry moisture and form clouds which leads to cloudy weather.

13 Experiment 12 Measuring Wind Speed 1 Paper Plate 4 Paper Cups Eraser tipped pencil Colored Scotch Tape Soft board pin Double sided tape Stopwatch 1. Stick a colored scotch tape around one of the cups to mark it. 2. Mark a cross on the plate with the help of a ruler to find its center. 3. Stick the 4 cups at equal distance at the edges of the paper plate. 4. Pass the pin through the center of the plate and attach it to the rubber end of the pencil. 5. Place the apparatus outside and calculate with the help of a stopwatch, how many times the marked cup passes in 30 seconds. 6. Record the values for different times of the day and make a chart. The instrument that you just built is called an anemometer and is used to calculate the wind speed in an area. Wind is produced due to air pressure difference between two areas and leads to various weather forms.

14 Experiment 13 Making a Wind Vane A4 sized chart paper Pencil Scissors Scotch tape 2 Kitchen skewers 4 clips Pen cap Compass 1. Find the top center of the chart paper, mark 2 diagonal lines from it to opposite ends and cut out a triangle. 2. Neatly fold the triangle and stick 2 coins with the help of a scotch tape inside the thinner side of the triangle. 3. Balance the folded triangle on a pencil and mark is center of gravity. Stick a pen cap with the help of a scotch tape on this center. 4. Stick the 2 kitchen skewers together and place the 4 clips in opposite directions at the center of the skewers. 5. Insert the top of the skewer into the pen cap attached to the card triangle. 6. The pointed vane of the triangle points in the direction from which the wind is coming. Use a compass to determine the direction of the wind. What you just made is called a wind vane and is used to determine the direction of the wind.

15 Experiment 14 Snowflake Beaker/Transparent Jug White Thread Sugar/Salt Metal wire Ruler Scissors Food Coloring 1. Take a metal wire and shape it in the form of a snowflake. Wrap it around with white thread. 2. Take boiling water in a beaker and mix sugar in it until the water saturates. 3. Add food color to the water in order to make the snowflake visible 4. Tie the snowflake to a ruler and suspend it in saturated water 5. Leave the beaker for 24 hours and then take out the snowflake. 6. It should have crystals of sugar deposited on it, which make it look like a real winter snowflake. The accumulation of sugar that you see on the snowflake is due to a process called crystallization. Ice crystals are a common sight in winters in the northern areas of Pakistan where rainwater freezes due to low temperatures while water droplets are drawn together in the clouds due to electrostatic forces in the clouds to form a variety of shapes of crystals.