Conclusion of convection

Watch the following video to revise Convection and also clear any difficulties you might have:

http://www.youtube.com/watch?v=ON2Y3FEk_UI

Also there is another website that you can visit to revise Convection. When entering the following site, click on 'Begin' and then click on the picture of the hot air balloon:

http://www.wisc-online.com/Objects/ViewObject.aspx?ID=SCE304

Revise well as questions will be asked when we meet in the next lesson!

Everyday examples of Convection- Lava Lamps

Lava lamps:

     Make a simple lava lamp!

Lava lamps also work with the principle of convection. Try out this activity to learn more about how lava lamps work.

http://www.physics.org/marvinandmilo.asp?id=5

Everyday examples of Convection- Sea and land breezes

Sea and Land Breezes:

a)   During the day, the temperature of the land increases more quickly than that of the sea. The hot air above the land rises and is replaced by colder air from the sea. A breeze from the sea results.

b)  At night the opposite happens. The sea has more heat to lose and cools more slowly. The air above the sea is warmer than that over the land and a breeze blows from the land.

For more information regarding sea and land breezes, visit the following link:

http://www.youtube.com/watch?v=gM0d3fGew-0

Everyday examples of Convection- Convection heater

Convection Heater:

One way to keep the home warm during winter is by using on a convection heater. But how does it exactly work?

These two animations will help you to learn more about how a convection heater works.

http://www.absorblearning.com/media/attachment.action?quick=6u&att=484

http://www.absorblearning.com/media/attachment.action?quick=af&att=742

Everyday examples of Convection- Air Conditioner

Air Conditioner:

Some of you might have an air-conditioner installed at home. During summer we switch it on to keep the room cold.

But do you know how the air-conditioner work? Why are air-conditioners never installed near the floor of a room? Try to answer these quesitons and write down what you know of the way air-conditioners work.

Everyday examples of Convection- Refrigerator

Refrigerator:


When we feel hungry the first thing we do is go and open the fridge to see what can we find good inside it. But have you ever thought how the food inside the fridge is kept cold?

Go and open the fridge found in your home. Can you see where the freezing unit of your refrigerator is found? Why do you think it is placed in this position?

Everyday examples of Convection- Electric Kettle

Electric Kettle:

What’s inside the kettle?

Have you ever wondered how a kettle works? Soon you’re going to find out!

At your home, find a kettle and open it. Write down what you have seen inside it. You can also take pictures and post them here.

Start posting!

Everyday exmaples of Convection- Hot Air Balloon

FUN FACTS ABOUT THE HOT AIR BALLOONS

  Hot air balloons were discovered in France in 1783.

  At that time, in the laboratory, it was discovered that a fabric bag filled with hot air could rise.

  In the beginning, to test for safety, balloons without passengers were sent up and observed.

  The next step was to send animals up to experiment with different weights. Sheep, chickens and even ducks were used.

  When everything was proven totally safe, a balloon with two men traveled over Paris for 5.5 miles, staying up 23 minutes.

  This was the very first attempt made by man to fly.

  Balloons have been critical to science as they have helped us study the weather and the atmosphere.

 



MAKE YOUR OWN HOT AIR BALLOON!

 

·      Find a suitable plastic bag. Dry cleaning bags work well, but smaller garbage bags may also be used if they are very light weight. Such trash bags usually boast of high molecular density which usually translates to super thin, cheap, and flimsy. That happens to be what we're looking for.

·      Attach straws together to form a circle with a diameter of about 12 inches. Do this without glue or tape by inserting the end of one into another and so on.

·      Tape the opening of the opened bag to the circle of straws. Use light weight tape, and use it sparingly.

·      Cut a 2 inch square out of thin cardboard like from that of an empty cereal box. Punch four holes near the center (the holes should be slightly smaller than the width of the birthday candles so that they will fit snugly).

·      Attach a twelve inch piece of thread to each corner of the cardboard square. Insert candles into the holes you punched. You may need to adjust the center of gravity for our cardboard candle holder to hang properly.

·      Connect the candle holder to the balloon's opening with the four threads from our candle holder so that it hangs down below the balloon. Make sure it is about a foot away from the balloon. Light it and let float!

Follow these easy instructions to build your own hot-air balloon! When you are finished you can take and post a photograph of your hot-air balloon so that we all can see what you have done!

Do you know how your hot-air balloon works? Share your ideas!

MR. BEAN’S RIDE ON THE HOT AIR BALLOON!

Watch this clip about when Mr. Bean went on a hot air ballon!

 

http://www.youtube.com/watch?v=hLYU3PudcF8

After watching this video, download the following worksheet and answer the questions:

Convection Currents in Liquids- Potassium Permanganate experiment!

Potassium permanganate experiment

http://www.absorblearning.com/media/attachment.action?quick=an&att=758

Click on the above link and click on the View online tab. Then click on the green arrow found at the bottom of the window. Basically this simulation consists of a beaker filled with water. Inside the beaker you can see a purple spot. This purple spot is a potassium permanganate crystal. When you play the simulation you can see the Bunsen burner switching on and colour from the potassium permanganate crystal spreading throughout the beaker. But as you can notice, the colour is spreading in a particular way and not at a random manner.

Can you come up with a solution to this experiment as to why the colour is spreading like this and not in another way? What is happening in to the liquid particles on the side where there is the Bunsen burner? Can you explain this in terms of density? Share your ideas and post your predictions and solutions on the blog. If you want you can even paint a sketch of this simulation with drawn arrows representing the direction of the water. After doing this you can upload your picture on the blog.

I will be demonstrating this experiment in class in the following days. In the meantime post your predictions and we will deal with them in class. Good luck!

Convection Currents in Liquids- Coloured ice cube experiment!

Coloured ice cube experiment

http://www.youtube.com/watch?v=QBVMm9i-pvo&feature=related

Click on the above link and watch the video. If you want you can try it at home. All you need is a transparent plastic cup, some warm water, food colouring and ice cube. After watching the video or trying it out yourself, try and answer these questions:

1.     When the ice cube started melting, what happened to the coloured melted water?

2.    Why do you think that the coloured meted water moved downwards?

You still cannot find a solution to this problem? Keep on reading.

Basically the process that is happening here in this experiment is called convection currents. Convection currents can be found both in liquids and gases. In this case, you are witnessing convection currents in liquids.

What is exactly happening to the ice cube? Due to the fact that the glass full of water is warmer than the ice cube, when the ice cube starts melting, cool water from it starts sinking to the bottom of the glass. Why does this happen? This happens because cool water particles vibrate less, take up less space, their volume decreases and density increases. Obviously something that is denser will sink to the bottom. That is what is happening to the melted ice cube! The green colouring is only representing the path of the melted water particles.

If you would like, you can record a video of this experiment and post it here and share your ideas with your classmates!!!!

Convection Currents in gases- Smoke Chimney experiment!

Smoke chimney experiment

Download the above picture. When you open the picture you will find a picture of a rectangle with two openings. The openings represent “chimneys”. Inside you can see a candle with a flame. At the opening of the chimney on the right side, you can see an incense stick. That is why this experiment is called the smoke chimney experiment.

When the incense stick is lit up, smoke enters the box from the right-hand chimney. Your job is to draw arrows representing the path that you think the smoke will follow. You can do this by copying the downloaded picture in a Paint program installed on your computer and drawing arrows where you think is correct. When you are ready, save the picture and upload it here on the blog and share your ideas on how you arrived at this conclusion.

Here are some questions that can help you conclude the arrow direction of the smoke:

1.     How is the air inside the box warmed?

2.    What will happen to the smoke when it enters the box? Why did this occur?

3.    What happens to the air just above the lit candle?

I will be demonstrating this experiment in class in the following days. In the meantime post your predictions and we will deal with them in class. Good luck!

Convection Currents in gases- Teabag Experiment!

Teabag experiment

Have you ever wondered how you can prove that hot air really rises upwards? Well here is one experiment which clearly proves this. Click on the below link:

http://www.stevespanglerscience.com/experiment/tea-bag-rocket

When clicking on this link you will find an experiment involving a teabag! You may ask: What can a normal teabag do? Well, read out the instructions under the Experiment Section to find out. As you can see, there are also pictures and a video to show you exactly how this experiment is done. If you still cannot figure out how this experiments works, you can find the answer in the Experiment Section under How does it work? part.

Always carry out this experiment in the SUPERVISION of an ADULT!

Don’t forget to share your observations with your classmates!!

Convection Currents in gases- Convection snake!

Convection snake experiment

http://www.physics.org/marvinandmilo.asp?id=14

Click on the above link and you will be directed on a Marvin and Milo comic. Marvin and Milo will explain clearly what materials you need and what you need to carry out to construct a spiral snake. If you do not understand the instructions found on this site you have the option to enter the below link:

http://www.dltk-kids.com/animals/mspiralsnake.htm

From this link you have the option to print out a ready-made spiral snake.

When you complete constructing the spiral snake you can take a photo of it and post it here on the blog for your classmates to see.

To carry out the experiment you need to put your spiral snake on a heat source. Examples of heat sources include a light bulb, candle and electric heater. Always carry out this experiment in the SUPERVISION of an ADULT!

After carrying out the experiment did you find out how the spiral snake works? Why does it swirl around? Why is the heat source important in this experiment? What does the heat source do to the spiral snake? Put your observations here!

Expansion 2

You managed to do the activity and why that happened?


Here's a video for you to understand what expansion is better and also to clear any difficulties you might have:


http://www.youtube.com/watch?v=I7w_Qv5_h4c

Expansion 1

Let's learn about expansion!

Do the following experiments at home with the help of an adult!

Balloon Expansion Experiment
Materials: saucepan filled with hot water, oven mitts or gloves, empty glass bottle (such as a ketchup bottle), rock or a weight to hold the bottle down, balloon

Put a balloon over the top of an empty ketchup bottle (you may need to put a rock in the bottom of the bottle for weight). Place the bottle in a saucepan of hot water.

After doing this experiment, posts your pictures here to share them with your classmates and also share your observations and why do you think this happened!

Penny Experiment
Materials: glass bottle with opening no larger than a penny, one penny, bowl of ice cold water.


Dip the penny and the threads of the bottle neck in the cold water. Put the penny over the opening of the bottle and wrap hands around the bottle.


After doing this experiment, posts your pictures here to share them with your classmates and also share your observations and why do you think this happened!

Let's see who posts pictures first!!

Density

The following videos will guide you to revise density.

The first link is about volume and density:

http://www.youtube.com/watch?v=rxb_6UANXqU

The second video is about buoyancy and it is a continuation of the previous video: 

http://www.youtube.com/watch?v=hkT3ulsGWyA&feature=related

Listen to the videos carefully as various questions will be asked after watching the videos and also it is important that you understand density before doing conveciton currents!!

States of Matter

• All matter around us exists in three states: solids, liquids or gases.
• The arrangement of particles inside solids, liquids and gases is not the same. Take a look at the diagrams shown below to learn more!

 The link below is a short video clip taken from Disney's Educational series: 'Bill Nye: The science guy'. This will serve as an introduction to the three states of matter:

http://www.youtube.com/watch?v=tBQcpF_j5Xg&feature=related

Now that you have watched the video, are you ready for some fun?? Click on the link below and explore how fun Physics is!! You can even do karaoke!! Try it out!

http://teacher.scholastic.com/activities/studyjams/matter_states/

And finally, you can try out this simulation to revise the  three states of matter:

http://phet.colorado.edu/en/simulation/states-of-matter