Thinking Allowed

green sine by bdu on flickr

New topic – yay!  We’ll learn about waves.  Here are some of the points we’ll try and answer:-

• What is a wave?
• What is the difference between transverse and longitudinal waves?
• What are some examples of transverse and longitudinal waves?
• What are the amplitude, frequency and wavelength of a wave?

Anatomy of Waves

We’ll then take a look at the wave equation       v = f λ

This shows us the relationship between speed of a wave v, the time it takes for a particle to vibrate up and down, and the distance between successive waves λ.  You’ll need your calculators as we practice solving problems in class.

Coal transport by MoToMo on flickr

For our culminating activity in this unit we will be getting you into groups and asking you to research, present and debate on which is the best source of energy for the Philippines.  Look at this handout for full details of the work, including the rubric for assessment.  Amended Energy Topic Performance Task

Each group of 4 students will be given one source of energy.  Each person on the group will take on a different role – either that of engineer, economist, environmentalist, or a  member of the public – and put together a convincing argument as to why their particular source of energy should be used.  You will also need to have some knowledge of other sources of energy in order to be able to counter any arguments against your source. 

Solar Panels by clownfish on flickr

You will be given 2 full lessons to research this.  The next lesson we will listen to each presentation, make some notes on this sheet: ENERGY PERFORMANCE TASK Presentation Notes and then vote on which energy source we think should be used.

This should be fun!

Current world oil reserves by ChartsBin on flickr

In class today we discussed the idea of exponential growth and watched this video by Chris Martenson.  We discussed the idea of peak oil, and how this was different to “oil running out” by watching this video.  We then researched which countries have oil reserves, and how much, and discovered that according to CIA world factbook, that the Philippines is #62 on the list.

We will discuss the following essential questions:

• Why have humans become so much more productive over the last 250 years when compared to the previous 250,000?
• What is peak oil, and should we be worried that some people say we have reached it?
• What will be the consequence of an ever increasing human population and falling fossil fuel energy reserves?
• Will developing countries ever realize the standard of living enjoyed by people in developed countries?

Imagine you are a carbon atom in a molecule of carbon dioxide in the air.  Close your eyes.  Really imagine yourself as that carbon atom.  Your task is to describe the journey you take from being part of carbon dioxide in the air, through the carbon cycle, until you return to the air again.  Here is my attempt at the beginnings of such a story to give you the idea.  You do not need to start in this way.  You decide.  Get creative!  Let your imagination work!

There I was, happily floating around in my usual gaseous form along with several of my brothers and sisters  (other carbon dioxide molecules), and my good friends nitrogen and oxygen.  We were having a great time bumping into one another, when I got dangerously close to a leaf.  Everyone had always told me to stay away from green plants, that I could get sucked into a stoma and never be seen again.  Before I realized what was happening, I was inside a chloroplast and going through a very fast reaction where I had to let go of my two oxygen atoms, and for a moment be entirely alone.  Before long, I found some other carbons and we joined together, 6 of us, 12 hydrogen friends and 6 oxygen buddies to form a glucose molecule….

Nature by jaxxon on flickr

We’re going to try and connect all that we have been learning – respiration, combustion, photosynthesis, food chains – into one big carbon cycle. This brainpop video will help get you started.  

This one on fossil fuels explains where oil, coal and gas come from, and leads into our next section on the importance of oil and how to separate it out by distillation.  This video explains how this works in an oil refinery. We’ll do a world energy audit and look at where the natural resources are and what the alternative energy sources might be.

fox chasing rabbit 0121 by pixpoils on flickr

What is a food chain?  It is a representation of energy flow through an ecosystem.  All food chains begin with a green plant, that traps energy from the Sun. We’ll look at lots of examples, and get to grips with terms such as producer, consumer, carnivore, herbivore, autotroph, heterotroph. 

Food chains have limited use in looking at the big picture in an ecosystem, since there is usually more than one organism feeding on each food source.  For a more realistic view of what happens in nature we need to consider food webs.  A food web is a number of inter-connected food chains.

Check out this brainpop video.

We’ll discuss the idea of interdependence between all the organisms within a food chain, and look at how disease or a change in the environment affects things.

We need to answer this important question:  why are food chains short (only 3 or 4 organisms long)?

We’ll use explorelearning to help us with these concepts.  Log in using the details given in class, type a search for food chains.  Follow the instructions for the food chain, praire ecosystem and forest ecosystem activities.  Enjoy!

And here are a couple more sites to help reinforce these ideas.  This one is from bbc science and this one allows you to explore a number of food webs.

This booklet by Mr Boulton might be useful for review and notes.Booklet to learn about ecology

photosynthesis in action by Sam Judson on flickr

Let’s suppose I want to redecorate my bedroom.  I need money to buy the materials, I need to know how to decorate, and I need the time to be able to do it.  Imagine that I am a good decorator, with a free weekend coming up, but I have no money to buy what I need.  The materials are the limiting factor in this instance.  The lack of paints, brushes, wallpaper, etc is what is stopping the process of redecoration.  Similarly, if I had money and knowledge, but was busy for the next month, then time would be the limiting factor.

Limiting factors apply to photosynthesis too.  We’ll discuss the factors that control how fast or how slowly photosynthesis proceeds, and analyse some graphs to help us understand this concept.

Is the main limiting factor for photosynthesis different in different parts of the world?  Or for different species of plants?  What do you think?

fine crop of rice by shop boy on flickr

Did you know that per 100g, carbohydrates and proteins contain similar amounts of energy whereas fats contain more than double that?  Actual figures are: 1760 kJ for carbohydrates, 1720 kJ for protein and 4000 kJ for fats (per 100g).

Differences exist between various ethnic groups in terms of their main dietary source of energy.  Your task will be to research different ethnic groups that use rice, wheat, cassava, maize, fish and meat as their staple energy source, and to compare their diets.

MSG by PunkJr on flickr

In addition, we will consider that there are social issues relating to inappropriate diets, especially in the developed world.  There is also highly effective marketing of unhealthy foods by profit-making companies (I saw a TV ad recently espousing the benefits of MSG!).  With this in mind, you must be able to explain the possible health consequences of diets rich in carbohydrates, fats and proteins. [Consequences of an excess of each type of nutrient should be explained separately.]

What makes us stop eating?  We have an appetite control centre in the brain.  Do some research and find out how it works.

Planet Earth by regulus2007

Each table will be given one of the following questions to research.  Find out all you can, remembering to discuss heat transfer in your answers.   Then we’ll share our findings with the class. The link below each question takes you to a youtube clip that will help to get you started.

• In winter, why is London warmer than Newfoundland?
• Ocean Odyssey – surface currents
• How is heat related to the formation of atolls, islands, mountains?
• South Pacific – Ocean of volcanoes
• Why are Europe and America moving apart geographically?
• The Earthly Earth and plate tectonics
• Why does it rain a lot in the Tropics but not in the Sahara? 
• Will the wet get wetter and the dry drier?

And our old friend Bill Nye has something to say on climate

Thermal Fluid Dynamics by Pro-Zak on flickr

This week we’ll be learning about the 3 different processes of heat transfer: CONDUCTION, CONVECTION and RADIATION.  To help us, we’ll be talking soccer and basketball – watch this space!

Here are some videos to help demonstrate:  Bill Nye 1, Bill Nye 2, Bill Nye 3

You might want to try answer the questions on this worksheet courtesy of Mr Boulton while watching: Heat Transfer – Questions For Understanding

To find out whether you’ve really understood the applications of heat transfer, you will be given a challenge.  See the attachment to read more   Have fun!  Heat Transfer Patent office modified version

The powerpoint I used in class is here: Topic 03 – Thermal Physics  The text is a little advanced for G9, but the images are good.