# Climate Change and Probability

Today is Blog Action Day 2009, billed as the largest, single,  social event on the web.  This years topic is “Climate Change”, a topic I have keen interest and passionate concern about. I first heard the term ‘global warming’  twenty years ago, as an undergraduate at LaTrobe University. Back then, the research was just beginning and the results weren’t conclusive – scientists are cautious by nature. Now, ‘climate change’ is a term we hear in the media every day and an issue being addressed at every level of government and in most private enterprises.

“New Scientist” has produced an excellent page to help you understand the facts of climate change at: “Instant Expert: Climate Change”.  Since the Earth Summit in 1992 and Kyoto in 1997, many countries have agreed to limit greenhouse gas emissions, in an attempt to reduce the enhanced greenhouse effect. In 2007 the IPCC announced that global climate change is “very likely” to have a human cause. In 2009, many thousands of scientists around the world agree that an increase in temperature of more than 2 degrees Celcius will have catastrophic effects on agriculture, biodiversity and water resources, as well as increasing the frequency of extreme weather events. The east coast of Australia experienced such an extreme weather event a few weeks ago, when an estimated 140,000 tonnes of soil per hour was collected from central Australia and dumped on the coast and offshore. This dust actually had an ocean-fertilizing effect – adding nutrients such as nitrogen and phosphoros to the ocean that enabled increased phytoplankton growth. It has been estimated that an extra eight million tonnes of CO2 was captured by this phytoplankton. Mother Nature fighting back?

Which of the objects above could you use in a probability experiment to simulate the birth of a boy or girl? How would you calculate the theoretical probability of three girls in a row? Draw a tree diagram to show all the possible combinations of three children.

# Year 7 and 8 Science and Maths – Week 2

This week in Maths we will continue to investigate probability, looking at both theoretical and experimental results and using technology to generate long term random results. We will be doing the Maths 300 activities “Dice Differences” and “Problem Dice”.

In Science, we will finish our Paper Aeroplane experiment and start individual projects. Go to the Science Buddies  site and complete the survey which will help you to identify areas of interest and suggest some projects that may be suitable. We will use the On-Line Science Fair wiki to post our research and share our results. Make sure you sign up as a member (using  your school email address and password) and create a page where you can keep relevant information and links.

In Year 8 Science we have started the Human Body unit with a look at the digestive system. This week we will be doing food testing, so make sure you bring in a small sample of food to test. These are the tests we will be doing:

1. Brown paper or Emulsion test for fats and oils (lipids).
2. Iodine test for Starch
3. Benedict’s solution and heat for glucose (sugar).
4. Copper sulphate (10 drops) and sodium hydroxide (5 drops) for protein.

# Today’s task – Year 7 Maths and Science

Firstly, congratulations for participating in the biological control of bridal creeper using leaf-hoppers, the DPI project we completed last term. The leaf hoppers we bred in class were successfully released at Hawkesdale Apex Park during the last week of term 3. We hope many of them survived the cold and wet weather we had over the September school holidays!

Today we will be looking at two tasks on the computers – (1) continuing our Beetle Game (Maths 300) to learn more about probability and long-range frequencies and (2) entering our paper aeroplane data onto the Google docs. spreadsheet to compare our results with other students.

(1) Go to Maths 300 on the intranet and choose “Beetle Game”. Click on “Make a Beetle” and then play ten games by clickoing on “Auto” and then clicking on the space bar. What do your results suggest? If this was a carnival game, how would you organise the cost and prizes so that you can make some money? Then go to “Make many beetles” and choose how many people you think will play the game at a school fete or carnival. How do you think you should organise the prizes now?

(2) Go to the Google spreadsheet “Paper Aeroplane Flight Distance data” and enter your results from five trials. Calculate the mean, using a calculator and then check using the formula option in the spreadsheet. Compare your results with other students’ – how did your plane go? How can you improve your design to increase your flight distance?

(3) If you have completed the above tasks, write a blog post about one of the three activities – releasing leaf hoppers to control bridal creeper, the “Make a beetle” game or Paper Aeroplane project.

# How many chocolate buds in choc-chip cookies?

Students enjoyed a Maths300 activity during Literacy and Numeracy Week, estimating the number of chocolate chips a manufacturer would need to add to a batch of ten cookies to try to ensure that each biscuit had a minimum of 7 chocolate buds. Initially some students believed that just a few more than 70 should suffice, while others decided the more the better and thought a few hundred should be added – just to make sure! After coming up with some ways to use random number generators to model the problem (10-sided dice, cards, throwing stones on a 2 x 5 grid) we used the Maths300 software to generate a stem and leaf plot for 100 trials. Following the activity, students estimated that between 110 and 150 chocolate buds were sufficient to have confidence that each cookie contained 7 choc buds. And now they want to make cookies…..