Grade 7: Physics | Diffusion

Have you ever touched something?

That became hot enough to burn you only moments after it was cool to the touch? This can happen when you stir a pot of soup on the stove with a metal spoon or roast marshmallows over a fire with a metal rod. So what explains why it’s a better idea to stir your soup with a wooden spoon and roast your marshmallows with a wooden stick? Objects made of metal can quickly conduct unwanted heat right up to our hands!

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Description

Objective

This skittles experiment is easy, low cost and provides lots of investigative opportunities. Try using different temperatures of water, white vinegar or even lemonade to discover what happens.

Materials

  • Skittles or sweets into a white container, you can alternate the colours.

Procedure:

SKITTLES EXPERIMENT INSTRUCTIONS

Place your skittles or sweets into a white container, try to alternate the colours.

Carefully pour water into the container, if the skittles move, just push them back into place quickly.

Watch what happens.

 

Results:

We can see the rainbow tails on the liquid.

Explanation:

WHY DO THE COLOURS SPREAD?

Skittles are coated in food colouring and sugar. When you pour water over the skittles the coloured coating dissolves spreading through the water.

The colour and sugar dissolve into the water and then diffuse through the water, making it the colour of the skittle.

 

EXTENSION IDEAS

Can you time how long the colours take to reach the centre of the plate using cold and warm water? Which do you think will be faster?

Try using other sweets, can you find any that work as well as skittles?

Disclaimer and Safety Precautions

Warning is hereby given that not all Project Ideas are appropriate for all individuals or in all circumstances. Implementation of any Science Project Idea should be undertaken only in appropriate settings and with appropriate parental or other supervision. Reading and following the safety precautions of all materials used in a project is the sole responsibility of each individual. For further information, consult your state’s handbook of Science Safety.

Safety

  • Put on protective eyewear. Conduct the experiment on the plastic tray and in a well-ventilated area.
  • Keep a bowl of water nearby during the experiment.
  • Keep flammable materials and hair away from flame.
  • Avoid looking directly at burning magnesium to prevent eye discomfort.
  • Do not attempt to extinguish the solid fuel and magnesium — let them burn down completely. Do not touch the stove after the experiment — wait until it cools down.
General safety rules
  • Do not allow chemicals to come into contact with the eyes or mouth.
  • Keep young children, animals and those not wearing eye protection away from the experimental area.
  • Store this experimental set out of reach of children under 12 years of age.
  • Clean all equipment after use.
  • Make sure that all containers are fully closed and properly stored after use.
  • Ensure that all empty containers are disposed of properly.
  • Do not use any equipment which has not been supplied with the set or recommended in the instructions for use.
  • Do not replace foodstuffs in original container. Dispose of immediately.
General first aid information
  • In case of eye contact: Wash out eye with plenty of water, holding eye open if necessary. Seek immediate medical advice.
  • If swallowed: Wash out mouth with water, drink some fresh water. Do not induce vomiting. Seek immediate medical advice.
  • In case of inhalation: Remove person to fresh air.
  • In case of skin contact and burns: Wash affected area with plenty of water for at least 10 minutes.
  • In case of doubt, seek medical advice without delay. Take the chemical and its container with you.
  • In case of injury always seek medical advice.
Advice for supervising adults
  • The incorrect use of chemicals can cause injury and damage to health. Only carry out those experiments which are listed in the instructions.
  • This experimental set is for use only by children over 12 years.
  • Because children’s abilities vary so much, even within age groups, supervising adults should exercise discretion as to which experiments are suitable and safe for them. The instructions should enable supervisors to assess any experiment to establish its suitability for a particular child.
  • The supervising adult should discuss the warnings and safety information with the child or children before commencing the experiments. Particular attention should be paid to the safe handling of acids, alkalis and flammable liquids.
  • The area surrounding the experiment should be kept clear of any obstructions and away from the storage of food. It should be well lit and ventilated and close to a water supply. A solid table with a heat resistant top should be provided
  • Substances in non-reclosable packaging should be used up (completely) during the course of one experiment, i.e. after opening the package.

Disposal

Dispose of the reagents and solid waste together with household garbage.

Additional information

Subject

Chemistry, Mathematics

Materials Needed

# 3 12-inch long metal rods or thick wire: copper, steel, brass, or other metal.
# 8 identical Styrofoam cups
# Something to boil water in (a pot or kettle)
# Stove
# 4 instant digital thermometers
# Pitcher or other large container that will fit in the refrigerator
# Water
# Notebook and pen

Topic

Astronomy

1 review for Grade 7: Physics | Diffusion

  1. admin

    Very glad to get the explanation of this science experiment.

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