Nutrition and the Digestive System

Learning Intention: Students will know the five groups of nutrients and how they contribute to a healthy diet. They will investigate the composition of various foods using food testing experiments, including various bush foods from the school garden and beyond. They will compare the diet of people living in Australia 10,000 years ago with their own diet.

Success Criteria: Students will produce a poster, video or other artifact that demonstrates their understanding of nutrition today and in Australia’s past. Their product will explain the five nutrients (carbohydrates, proteins, lipids, vitamins and minerals) and the foods in which these nutrients are found. The importance of fibre and water in the diet will also be discussed.

Links to AusVELS: “Multi-cellular organisms contain systems of organs that carry out specialised functions that enable them to survive and reproduce.”
“Energy appears in different forms including movement (kinetic energy), heat and potential energy, and causes change within systems.”
“Also, links to cross-curricular priorities – Aboriginal and Torres Strait Islander histories and cultures.”

This term we started a new topic of work – nutrition and the digestive system. We have discussed the five main nutrients and the importance of water and fibre in a healthy diet. We have also used the model human torso and watched videos to understand how the digestive system works. Mr John Pearce (@mrpbps on Twitter) has shared this wonderful hands-on “Tour of the Digestive System” that we may try too. Parts of Plants we Eat.

We will learn how energy is measured and the energy content of some different foods, using the nutritional information of food labels. Our next tasks will include using various tests to determine what nutrients make up different foods. We will do the following tests:

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.

We will then collect some bush foods from the school garden and Apex Park and test those foods for starch, protein, sugars and lipids. You will then create a product that compares the diet of people in Australia 10,000 years ago to your diet. You may have heard of the “Paleo diet” (also called the “caveman” or “stone-age” diet). It consists mainly of fish, meats, eggs, vegetables, fruit, fungi, roots and nuts and excludes grains, legumes, dairy products, potatoes, salt, sugar and processed oils. What would Bear Grylls survive on in the Australian Bush?

Some useful links:

 

Simple Circuits

We have done several experiments over the past few weeks to learn more about how simple circuits work. You have created a circuit using just a battery, globe and two wires and then constructed your own switch to turn the globe on and off. You then constructed your own torch from two batteries, a globe, cardboard tube, wires, aluminium foil, drawing pins, paper clips and sticky tape. Many of you were able to operate your torch using just one hand – great work! Unfortunately, we were unable to create a circuit with enough voltage to allow a small LED globe to operate using lemons.

We then looked at series (one pathway for the current to flow) and parallel circuits (more than one pathway for the current to flow). We learnt about ammeters and voltmeters and how they are connected. An ammeter measures current in amperes and is connected in series. A voltmeter measures voltage in volts and is connected in parallel across the load (globe, buzzer or other device). Find out more about series and parallel circuits at BBC Bitesize. Ausgrid also has some good information about  series and parallel circuits.

There is an interesting article from ABC Science here: “In this universe, charge is everything” and here: “How electricity makes things work.”

Landing Time of a Parachute – Air Resistance

Creative Commons image from Wikimedia

Learning Intention: To investigate the effects of forces and to design, carry out and report on a simple practical experiment with controlled variables.

Success Criteria: Students will design and carry out an experiment to find out the effect of different factors (mass of object, size of canopy or shape of canopy) on the landing times of a parachute with a toy (Barbie, toy soldier or Lego man) attached. They will vary only one factor, collect data to gain an average of at least three ‘jumps’  and record their results in a table. Students will complete a report of their investigation that includes Aim, Method, Materials, Results, Discussion and Conclusion.

When objects are dropped from a height, gravity is not the only force acting upon them. You would feel the other forces if you jumped from a plane, as air resistance. The picture above shows the design of the world’s first human parachute – can you think of any animals use air resistance to aid movement?

Your task this week is to find out the effect of one of the following variables (something that changes) on the landing time of a parachute. You can use cotton or nylon thread to attach the parachute and drop it from at least two metres.

  • Mass of the skydiver (use a Barbie doll, toy soldier or Lego man with weights added)
  • Size (area) of the canopy (use plastic freezer bags or garbage bags)
  • Shape of the canopy

Make sure that only one of these factors changes and repeat each trial at least three times. Draw up a table to record your results.

 

Year 7 Science: Forces

Magnet and Compass

Click to Run

 

 

Interactive Learning Object from PheT, Colorado

Learning Intention: Students will understand that forces can start motion, stop motion, change the speed or direction of motion, change the shape of an object or have no effect at all. They will be able to distinguish between contact forces (friction, buoyancy, surface tension, mechanical forces) and non-contact forces (magnetic and electric forces).

Success Criteria: Students will create a 60 second science video that demonstrates their understanding of forces.

This term Year 7 students will continue learning about forces, using simple experiments with magnets, water, weights and wires. We will also use some online and netbook tools to learn about forces. Click on the interactive above to enter the learning object. Read more about the magnetic field of the earth at BBC Bitesize: Magnetic Fields.  Do-it-Yourself magnetic levitation at You Tube. Everything you ever want to know about magnets from the Cool Magnet Man. 

Your task this week is to produce a 60-second science video that demonstrates your understanding of forces – choose one of the forces we have discussed (magnetic, friction, static-electric, buoyancy, surface-tension, gravity, muscular and mechanical forces). Create a story board and a script before you borrow the cameras and start filming and editing. You will need to register on the site using a username and password before you upload your video.

Year 9 Science: Electrical Circuits

Image Source

Learning Intention: Students will be able to distinguish between current and voltage and know how they are both measured. They will be able to describe the components of an electrical circuit (switches, loads, resistors, capacitors, cells, insulators and conducting wires) and how they work. Students will be able to construct simple series and parallel circuits and add ammeters and voltmeters to measure current and potential difference. They will understand the relationships between power, energy and time and describe in quantitative terms the relationship between current, resistance and voltage in a variety of electric circuits.

Success Criteria: Students will build a variety of series and parallel circuits and draw their corresponding circuit diagrams. They will perform a variety of practical experiments to measure voltage and current and calculate resistance. They will be able to describe circuits and how they operate using the correct terminology.

This online game, ElectroCity, is a great way to learn about energy, sustainability and environmental management. As the city mayor, you make decisions about the construction of electricity generation plants (coal, gas, solar, nuclear, wind or ocean?)  and where residential and industrial development occurs. If you play the game, add the code BG28135 so I can track your progress.

Year 7 – Separating a Mixture

Last lesson the Year 7 students were given a mixture of salt, sand, iron filings and rice. Their task was to separate the mixture into it’s components, trying to conserve as much of the material as possible. This is the slideshow that previous year’s students prepared, showing how they went about the task.

Creating a Dichotomous Key

lollies2

Learning Intention:
Students will understand how a dichotomous key is used to classify and identify organisms in the living world.
Success Criteria:
Each student will produce a digital or paper-based key that uses objective, yes/no questions to identify lollies from a mixture.
Year 7 students are doing a unit on Classification of Living Organisms and learning how to create a dichotomous key. A dichotmous key is what scientists and taxonomists use to identify living organisms. We used mixed lollies and asked the following yes/no, objective questions:

1. Is it hard?
2. Is it circular in shape?
3. Does it have a hole in the middle?
4. Is it sugar-coated?
5. Does it contain chocolate?

Here is one that Sophie created using Bubbl.us:

lollies_Sophiex450

Dark and Stormy Night

Nick&James_torch

Learning Intention:
Students are learning to identify the important components of an electric circuit and describe how it works.
Success criteria:
You will be able to collect the materials and connect them together to create a torch which includes a globe, switch, wires, batteries and reflector.

This week you will draw what you think is inside a torch (without dismantling it!) and then, after some discussion about the essential components, construct your own torch from simple materials. Imagine you are driving down the back paddock with Dad, and you get bogged in the ute. Dad has to walk back to get the tractor, to pull the ute out. It’s getting dark, so Dad tells you to wait in the car until he gets back. You look in the glovebox and find the following materials:

Batteries
Wires
Sticky tape
Drawing pins
Aluminium foil
Cardboard tube
Paper
Paper clips

You unscrew the globe from the overhead light in the ute and start to make a torch. Your torch needs to be operated with one hand, and have a switch that turns the light on and off. A good torch will be able to direct a beam of light and have no loose wires or dangly bits. When you have finished please leave me a comment about what you found easy, what was more difficult and what you learnt from this activity. What do you think is the most important part of the torch?

Chemical Reactions

chemical reaction collage

Collage created using Photovisi 

Learning Intention:To distinguish between physical and chemical change and know how to influence the rate of a chemical reaction.

Success Criteria: You will be able to identify common chemical reactions and write word equations. You will be able to list the ways in which you can increase or decrease the rate of a reaction.

Year 8 students have started a unit of work learning about combustion, rusting and other oxidation reactions, acids and bases. This site, “Science Clarified”, has a good list of the different types of chemical reactions, with some examples and cool pictures.  This short video, from the BBC, “Factors affecting the rate of chemical reactions” explains some of the ways that you can change the rate of a chemical reaction.

Students have performed several experiments to show the results of chemical reactions:

  • Change of colour (new products formed)
  • Gas production (new products formed)
  • Precipitate formation (new products formed)
  • Change of temperature (release or absorbtion of energy)
  • Light or sound produced (indicating energy has been released)

Students have also performed an experiment to demonstrate how grass can be turned into paper, using a series of physical and chemical reactions. Each student produced a slideshow about these reactions.

  • Cutting and crushing the grass (Physical)
  • Digesting the grass with caustisc soda (Chemical – colour change)
  • Washing the grass fibres (Physical)
  • Bleaching the fibres (Chemical – colour change)
  • Washing and Forming the paper (Physical)

“Five Major Chemical Reactions – video” and “Five Major Chemical Reactions – animations” are short videos from from YouTube. This blog from another Year 8 Science teacher has some great information you may be interested in: “Ms. Saenz at Mclean Middle School”. Marilyn Winter created this great Glogster about chemical reactions. Chem4Kids has a good article about “Rates of Reactions”.

Chromotography with Smarties and Autumn leaves

smarties#2

Chromotography  is a collective term for a set of laboratory techniques used to separate mixtures. It includes paper chromotography, thin-layer chromotography and gas chromotography. Paper chromotography is used for separating mixtures such as inks and dyes. In our practical experiment, we will use the natural food  dyes used to colour “Smarties”, although the artificial colouring used for “M and M’s” work well too. This is also a great time of year to investigate the pigments in autumn leaves – as chlorophyll breaks down to produce xanthophyll, carotene and anthocyanin. Another experimental method for leaf chromotography here.

Why do some trees have leaves that change colour in the autumn? How is chromotography used by forensic scientists and in industry? Please do some research and post your answers in the comments section below.