Acids and Bases

Learning Intention:
Students will understand that the pH scale ranges from 1 (acid) to 7 (neutral) to 14 (basic). They will understand that acids release a hydrogen ion in solution and alkaline substances release an hydroxide ion. Substances can be tested using an acid-base indicator such as litmus paper or purple cabbage indicator. The colour change that occurs is another example of a chemical reaction.

Success Criteria:
Students will make an acid-base indicator by boiling red cabbage and straining the liquid. They will then test a range of household substances, including cleaning products, vinegar and lemon juice and determine whether they are acids or bases. Students will then use indicator paper to check their results and arrange the substances from low pH (most acidic) to high pH (most basic).

Our assessment for this unit of work will be a test on Thursday during period 5. Use Pages 76 and 77 of your textbook for revision. You may like to try this quiz at Quiz Revolution. These videos at How Stuff Works are also good revision for the test.

Seven Reactions that will fascinate your science class – Five of these reactions are chemical reactions (what are the indicators for a chemical reaction?) and two are physical changes. Which two are physical changes?

Sulfuric acid in sugar (video)  – What are the signs that this is a chemical reaction?

Sodium metal in water (video) – What are the signs that this is a chemical reaction?

Chemical Reactions – Rusting

Learning Intention: Students will understand that rusting is another type of chemical reaction, in which the products of the reaction are different to the reactants. They will also learn about the process of planning and conducting an experiment, devising an hypothesis and using a control with variables.

Success Criteria: Students will plan and conduct an experiment that tests an hypothesis about rusting.

You will be familiar with ‘rust’ as the orange/brown corrosion that affects some metals. Farmers, engineers, sailors and car-makers are all very aware of the economic impact of rusting. Rusting is a chemical reaction that occurs when metals are exposed to moisture and the air. How Stuff Works has a good article about rust – “How does rust work?”. Read pages 60 and 61 in your text book. Your task is to devise an experiment to investigate rusting. You may like to test the effect of the saltiness of water on the time taken for an iron nail to rust. You may like to test some methods that are used to reduce or prevent rusting. Follow these steps:

  1. Write an hypothesis – a theory about rusting that you want to test. For example, “The greater the concentration of salt, the quicker iron will rust.”
  2. What will be the ‘control’ and the ‘variable’ in your experiment?
  3. Write a list of materials and equipment that you will need to complete the test. Submit your list of requirements to me so we can be sure we have everything you will need.
  4. Formulate a method that describes exactly what you need to do – make sure someone else can use this method to repeat the experiment in exactly the same way you have done.
  5. In your method you need to include how you will record your results – will you measure mass, time, volume, temperature or some other factor/quantity?
  6. Undertake your experiment, recording your results.
  7. Include a discussion of your findings in your report. Were there any sources of error or unexpected results?
  8. Write a conclusion that refers to your original aim/hypothesis. Did you prove or disprove your hypothesis? Do you need to do further experimentation?

Making Paper from Grass

 

Paper made out of banana tree

You use stacks of paper every day but do you know how it’s made? Paper has been made since 105 AD in China, but other materials such as papyrus (in Egypt), parchment and vellum (various grades of mammal skin) were used in other parts of the world prior to this. Find out more about the history of paper at Wikipedia.

In Sri Lanka, a fair trade company is making paper from elephant pooh! In that country, humans are encroaching on elephant habitat, cutting down trees for fire wood and shooting and killing elephants that come looking for food. This company, “Mr. Ellie Pooh” aims to create employment and encourage villagers to see the elephants as an asset rather than a threat.

Compared to using virgin wood, paper made with 100% recycled content uses 44% less energy, produces 38% less greenhouse gas emissions, 41% less particulate emissions, 50% less wastewater, 49% less solid waste and — of course — 100% less wood.

This week we are making paper from grass in six steps:

  1. Cut the grass and grind it with the mortar and pestle
  2. Add caustic soda to release the cell contents
  3. Wash and rinse to remove chemicals and cell contents
  4. Add bleach and bring to the boil
  5. Wash and rinse to remove the bleach
  6. Form the paper

Which of these steps are physical changes and which are chemical changes?

The Carbon Cycle

Created using Comic Life

Learning Intention: Students will understand the processes involved in the carbon cycle – photosynthesis, respiration, decomposition, combustion and fossil-fuel formation.

Success Criteria: A product that demonstrates their understanding by providing an explanation of each of these processes.

Your assessment task for this unit of work is to produce an artefact that explains your understanding of the carbon cycle. It might be a poster, video, Voicethread, cartoon or slideshow. You could use Comic Life, ToonDoo, a common-craft style video or another tool. Make sure you include the following processes:

  • Photosynthesis – green plants use sunlight to convert carbon dioxide and water into carbohydrate (glucose) that is used by all other living organisms as the source of food. (absorbs CO2 and H2O and releases O2)
  • Respiration – all living organisms (with the exception of a few bacteria) use oxygen to convert carbohydrates into energy, releasing carbon dioxide and water into the atmosphere. (Requires O2 and releases CO2 and H2O)
  • Decomposition – Bacteria and fungi break down organic matter (leaves, wood, dead animals etc) into carbon dioxide and water during respiration.(Requires O2 and releases CO2 and H2O)
  • Fossil Fuel formation – Oil, coal and gas are formed after millions of years under extreme pressure and high temperatures, from once living organisms such as trees and microscopic algae.
  • Combustion – wood, gas, oil, coal and other carbon-containing compounds can be burnt with oxygen to produce carbon dioxide. (Requires O2 and releases CO2 and H2O)

Some useful resources:

Elements and Compounds

Image Source

So far this year, you have learned about the following:

  • An atom consists of positively charged protons and neutrons with no charge in a nucleus in the centre of the atom and much smaller electrons, which are negatively charged and on the outside of the atom.
  • Molecules are tiny particles made up of more than one atom. A water molecule is made up of two hydrogen atoms and one oxygen atom.
  • Elements are pure substances that are made up of one type of atom. There are 92 naturally occurring elements and some man-made elements.
  • Compounds are substances made up of more than one type of atom, tightly bound together. They can look and behave very differently to the elements that they are made up of.
  • Elements are organised in the periodic table according to the number of protons in their nucleus. Hydrogen is #1 because it has one proton, helium is number 2 because it has 2 protons etc.
  • Each column of the periodic table contains elements with characteristics in common – the noble gases in Group 8 are all very non-reactive elements for example.

Your assessment task for this unit of work is to produce an artefact that explains your understanding of the carbon cycle. It might be a poster, video, Voicethread, cartoon or slideshow. You could use Comic Life, ToonDoo, a common-craft style video or another tool. Make sure you include the following processes:

  • Photosynthesis – green plants use sunlight to convert carbon dioxide and water into carbohydrate (glucose) that is used by all other living organisms as the source of food.
  • Respiration – all living organisms (with the exception of a few bacteria) use oxygen to convert carbohydrates into energy, releasing carbon dioxide and water into the atmosphere.
  • Decomposition – Bacteria and fungi break down organic matter (leaves, wood, dead animals etc) into carbon dioxide and water during respiration.
  • Fossil Fuel formation – Oil, coal and gas are formed after millions of years under extreme pressure and high temperatures, from once living organisms such as trees and microscopic algae.
  • Combustion – wood, gas, oil, coal and other carbon-containing compounds can be burnt with oxygen to produce carbon dioxide.

Year 8 Science: Atoms and Molecules

Learning Intention: Students will be able to recognise the structure of atoms and molecules and understand some of the features of the periodic table. They will know that elements are pure substances made up of a single type of atom.

Success Criteria: You will be able to define atoms, molecules, elements and compounds. You will be able to draw a labelled diagram of an atom and explain why elements are arranged in the periodic table in rows and columns.

As you discovered this week, chemistry is everywhere! All substances are made up of atoms and molecules whether they be gases, liquids or solids. Some are pure substances (elements) made up of one type of atom, but most are compounds, made up of molecules of atoms of different kinds. We will complete several experiments next week, that show that a compound can be very different from the elements from which it is comprised. For example, hydrogen(H2)  and oxygen(O2) are colourless gases, but H20 (water) is a colourless liquid. Carbon (C) can be like charcoal, graphite or diamond, but carbon dioxide (CO2) is a colourless gas.

More information about atoms and elements at BBC Bitesize and the NDT Resource Centre.

Year 7 and 8 Skills 4 Living – Your survival kit

Image source

Learning intention: Students will have a greater understanding of the necessary goods and services provided in our community and their importance for survival. They will consider the requirements to be self-sufficient, in terms of food, fuel, shelter and medicine.

Success criteria: Each student will prepare a “virtual survival kit” (report, poster or slideshow) that lists all the necessary requirements to survive indefinitely in an isolated location. 

Over the past couple of weeks most of you have experienced what it is like to be without telephones, internet, ATM’s and EFTPOS. You have also probably had times when there was a power failure, the tanks ran out of water or the gas bottle was empty. Often we take all these products and services for granted – we expect that we will always have access to electrical lighting; heating and cooling; cooking and washing appliances; waste disposal; communication and entertainment devices.

However, sometimes natural and man-made disasters occur (floods, bushfires, tsunamis etc) and all these goods and services are unavailable. There are groups of people who plan for such events – sometimes called “preppers” or “survivalists”. Some even believe in an apocalypse (doomsday or end of the earth as we know it). Your task today is to prepare a virtual “survival kit” to document what you would need in the case of some disaster that prevented you getting anything (food, water, power, shelter or any other materials and equipment) from outside this school. Can you think of any movies that begin with this premise?

You will need to grow your own food, because you cannot store enough to survive in the long term. You will need some way of producing energy if you wish to extract water from the ground and have hot water and lighting. Your report, poster or slideshow should include a list of requirements and a description of how they will be used.

Some resources:

Please add any other resources in the comment windows below.

Year 8 Skills for Living – Apollo Bay Camp

Learning Intention:

Success Criteria:

Your task today is to write a blog post about last week’s camp. Please include the activities you enjoyed, what you learnt and the most memorable part. You may like to use these prompts…..

  • The most difficult thing about being on camp was….
  • The best food we had was……
  • I will always remember when….
  • The funniest part was when….
  • The interesting thing about staying in a YHA is….
  • I was happy to get home because….

Year 7 and 8 Skills for Living – “A Winter’s Tale”

The Bollywood dancers – Year 7 girls

Your task today is to write a blog post, including an image, about the production. You can find images of the production in the “student public folder > 2012 > Production photos”. You could write it as a newspaper review, including what you enjoyed about the performance and how it compares to other shows you have seen. Or you could write it as a performer – what you felt before, during and after the show. Make sure you include the following:

  • a description of the characters and the setting
  • the storyline – what is the show about?
  • what are the highlights?
  • who were the ‘behind the scenes’ team who made the show such a great success?

If you didn’t participate in the production and didn’t get the opportunity to see the show, write a review of your favorite TV show or movie. You will still need to include the four dot points above.

Year 7 and 8 Skills for Living

Each student needs to reflect on their Semester 2 Learning Goals and send a statement through to me by email. Each student has

  • 3 academic (subject-related) goals,
  • 2 “You Can Do It!” goals (confidence, resilience, persistence, organisation and getting along) and
  • 1 personal goal.

For student reports, I need to write a paragraph about how each student has achieved or not achieved their goals. So, students should write about each goal and state wether they have achieved their goal and if not, why they didn’t. Are your goals still relevant? How can you make sure you achieve these goals this term or next year? Send to me at brittgow(at)gmail(dot)com.