2024
Onion
Prepare a thin layer of onion skin in water. Observe this layer at moderate magnification. Touch a salt powder with a wet needle. Place a few salt crystals in the field of view such that the crystals are visible in the microscope. Observe the behaviour of the onion cells. Perform a similar experiment with sugar crystals and compare the results. Explain the observed phenomena.
pH Indicator
The juice of many fruits or vegetables contains a natural pH indicator that changes colour according to the pH of the solution. Investigate such pH indicator juices and their mixes. Propose the most precise and effective composition and compare its properties with those of common indicators.
Microwaves
It has been claimed that you should always place the food on the edge of the microwave carousel, instead of in the middle. Do experiments to determine if this is correct.
Lemon juice
Measure the amount of vitamin C in a substance such as lemon juice. Investigate the effect of heating the substance on the amount of vitamin C you measure.
Heating water
Find the most energy efficient way to make a cup of tea.
Disappearing Ink
Disappearing ink becomes invisible shortly after being used to write a text on paper. The paper can be processed to make the ink visible again. Suggest a chemical formulation for such an ink. Investigate parameters that determine the time for the text to become invisible, and to become visible again.
No Tournament held
1. Bright Coins
Tarnished coins can be cleaned using various household substances and methods. Compare the effectiveness of various methods and explain how they work.
2. Trampoline
Bounce a small ball off a rubber membrane. Investigate how its bounce depends on relevant parameters.
3. Potato Osmosis
If chunks of potato are placed in fresh water or salt water, the appearance and physical properties of the potato can change. Explain this effect and investigate relevant parameters (e.g. salt concentration).
1. Apples
Apple slices turn brown after being cut. Investigate the speed of this process and test methods to prevent browning of apple slices.
2. Meat Tray
Supermarket meat trays often have a pattern on the bottom that will hold liquid in the tray even when the tray is turned upside down. Explain this phenomenon and investigate the parameters that affect the amount of water that can be held by an upside down tray.
3. Slinky
Suspend a Slinky vertically by holding it at one end. Release it and let it fall
freely. Investigate the characteristics of the Slinky’s free-fall motion.
Vegan Milk
Plant based 'milk' products are very popular and there are many online recipes.Try out one or more recipe and investigate how plants can make a liquid that is similar to cow's milk. Explain similarities and differences.
The strength of the sun
UV protection is important in New Zealand, but the risk of sun damage varies depending on the season and the weather. Sometimes people forget to use sunblock and they don't realise that they are getting sunburn. How can you (safely) measure the sun's "strength". Investigate the conditions which may cause people to misjudge the "strength" of the Sun.
Pingpong ball
Maximise the distance of flight for a ping-pong ball. Investigate, scientifically!
Colourful bouquet
You can make a white carnation become coloured if you put it in a vase containing dye. Investigate this effect with other flowers and plants in various solutions. What factors affect the final colour of the flower/plant and how fast can you get the colour to change?
Soap Boat
Make a simple boat by putting soap or detergent into a notch on a piece or card or plastic. Explain how it works and investigate how the speed of the boat and the distance it travels depend on various parameters.
String telephone
Sound can be transmitted along a string connecting two containers. Investigate how the intensity of the sound and the quality of communication between the transmitter and receiver depending upon distance, tension in the line and other relevant parameters.
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