week2

science in the kitchen

SCIENCE IN THE KITCHEN

Young scientists get ready! Explore the fun of science in your own kitchen with the help of EdPlace. Here`s some exciting science experiments and projects that you can easily do at home. Keep your teeth healthy using eggs or demonstrate pH levels by making a red cabbage indicator. It’s time to turn your kitchen table into a science lab!

PRIMARY SCHOOL - LEARN ABOUT THE EFFECT OF SUGAR ON TEETH

This easy activity helps you learn how food affects your teeth and why it’s important to clean teeth to keep them healthy. Once our milk teeth have been replaced by our adult teeth, we really need to look after them - they have to last a lifetime! Sugary, sticky food sticks to the surface of teeth where bacteria break down the sugar to make chemicals called acids, which can cause damage.

We can’t experiment on our own teeth, but as the shell of an egg is made of a similar substance to tooth enamel we can use eggs instead!

IT’S EXPERIMENT TIME!

You’ll need:

  • tick Eggs
  • tick Jars/Containers
  • tick Water
  • tick Tea/Coffee
  • tick Fizzy flavoured drink
  • tick Vinegar
  • tick Toothpaste

Instructions:

  • 1. Pour the same amount of fizzy drink, vinegar, water and tea or coffee into your jars.
  • 2. Add a whole raw egg still in its shell to each jar.
  • 3. Leave for approximately three days.
  • 4. Remove the eggs.
  • 5. Rinse the egg kept in vinegar and rub gently until the shell comes away.
*You should use the same amount of test substances for each egg. This is to make the comparison between them fair.

Extension task

Cover one egg with toothpaste and add to a separate container containing coffee, leave for 3 days.

workshop Results & other `Egg-citing` Activities

Can you see staining on both the fizzy drink and tea/coffee egg? Uh, yuck! Fizzy drinks, coffee and tea cause the same effect on our teeth too! Just imagine, smiling may be a problem when you have stains on your teeth…

Another trouble with sugary foods is that bacteria in your mouth love them. When you eat sweet things some of the sugar gets stuck in all the cracks and crevices in and around your teeth. The bacteria start munching and, as they do so, an acid is released that attacks your teeth - that`s why sugary foods need cleaning away quickly!

What about the toothpaste covered egg? We found our toothpaste covered egg stained less than the eggs not covered in toothpaste. Interesting, isn’t it?! Do you know the reason?

Fluoride is a chemical added to toothpaste to make it more effective at fighting decay. It also helps strengthen teeth.

After this exercise hopefully you can see that with proper care and a balanced diet, permanent teeth can last a lifetime!

Oh, wait! What happened with your vinegar covered egg? On ours the vinegar completely dissolves the eggshell, leaving just the membrane behind.

Why does this happen?

  • Vinegar (which is acidic) dissolves the calcium carbonate in the egg shell, leaving just the membrane intact.
  • You should also see the egg swell up, because some of the liquid seeps inside it via osmosis. (Osmosis is the movement of water from a less concentrated solution to a more concentrated solution through a partially permeable membrane).
  • Tea is rich in tannins, which stain teeth if they’re not cleaned properly while cola and fizzy drinks contain substances that will stain and are also acidic.

Can you bounce the egg with no shell?

Try dropping from different heights or onto different surfaces. Remember when you test to only change one variable, so change either the surface or the height not both.

Try cleaning the stained eggs carefully with different style of toothbrush and types of toothpaste. Does adult toothpaste work better than children’s toothpaste?

Try leaving an egg with no shell in water for a couple of days, it should increase in size as the membrane is semi permeable and allows water to pass through.

Did you know?

Different shaped teeth have different purposes? Flat molars like humans have are for grinding and chewing food, while sharp canine teeth are for tearing food apart (these are found in carnivores) and large incisors for cutting and chopping grass (found in herbivores).

Teeth are not just for eating, animals often use them to defend themselves or to attack other animals.

Cleaning teeth, using floss and mouthwash help keep teeth and gums free from plaque. Plaque is formed by bacteria which feed on the sugar left on the surface of teeth, this is why it is important to clean teeth properly.

Task: Describe the importance for humans to exercise, eat the right amounts of different types of food, and hygiene.

ONLINE TUTORIAL WORKSHEETS

Here’s some relevant topic areas of Human Body, Healthy Diet and Teeth recommended by our Science teacher, designed to help young scientists.

See more worksheets here

SECONDARY SCHOOL - HOW TO MAKE A RED CABBAGE INDICATOR

Did you know you can make a pH indicator solution using just red cabbage and water? Wow, let’s figure out how! But first some facts...

A pH indicator changes colour when added to an acid or alkali. Acids and alkalis can be found in a chemistry laboratory, but also in our houses! Acids are substances with a tangy taste... that`s right, like lemons. The most common laboratory alkali is sodium hydroxide. Alkalis, generally, feels a bit like soap. Today, most cleaning products are alkalis, for example, toothpaste, soap and oven cleaners.

The red cabbage indicator turns red when mixed with something acidic and green when mixed with a base (alkaline solution). If a solution is neither acidic nor alkaline we say it is neutral, this is pH 7.

The pH scale is a measure of how strong or weak an acid or alkali is. It is a continuous scale from below 0 to above 14. The colour chart below shows the colour that universal indicator turns when it’s mixed with solutions of different pHs.

  • neutral solutions are exactly pH 7
  • acidic solutions have pH values less than 7
  • alkaline solutions have pH values greater than 7
  • the nearer to pH 0 you go, the more strongly acidic a solution is
  • the nearer to pH 14 you go, the more strongly alkaline a solution is

The pH scale is commonly used in all walks of life from gardening to pet care. As a result, pH indicators can be purchased from DIY and pet stores. You could always ask your parents if they can buy one, and then you can test the pH of substances around your home!

RED CABBAGE INDICATOR EXPERIMENT

In the following video we`ll be mixing different solutions into our red cabbage pH indicator and watch how the colour changes based on the pH of the solution. We`ll show you how you can explore this topic at home with some simple household items.

You`ll need:

  • tick Red Cabbage (chopped)
  • tick Saucepan
  • tick Water and a source of heat
  • tick Sieve
  • tick Containers
  • tick Substances to test - lemon juice, baking soda, alka seltzer and vinegar all work well

SAFETY NOTE:

Wear safety goggles if using strong acids/bases. An adult should help with the heating of the cabbage.

Instructions:

  • 1. Place the chopped cabbage into a pan and add enough water to completely cover.
  • 2. Heat for about 10 minutes or until the water turns purple. Remove the heat and leave to cool.
  • 3. Once cool, strain the cabbage water into a large container and divide evenly between your test tubes or glasses.
  • 4. Add one substance to each glass and observe the colour change.

worksheet Results & Extension Ideas

The substances that turn the water red are acids and those that turn the water green are weak bases, alkalis. Acids and alkalis are opposites, acids have a low pH and alkalis have a high pH.

Why does this work?
It turns out that red cabbage contains a chemical called anthocyanin that changes colour depending on the acidity of its environment. In an acidic environment it is reddish-pink, in a neutral environment it is purple, and in a basic (or alkaline) environment it turns bluish-green and even yellow.

- Try testing other safe household substances such as fizzy drinks, salt, soap or milk. Can you predict whether they will be an acid or alkali and then test to see if you’re right?

- Try blowing into the indicator with a straw. You should find the indicator turns red as the carbon dioxide in your breath reacts with the water to form carbonic acid.

- Can you make your own pH indicator strips? Soak filter paper in the red cabbage indicator and leave to dry. Once dry cut the filter paper into strips and dip into your test substances.

- Try using beetroot juice instead of red cabbage, which works the best?

Limescale, which can form in kettles, is an alkali. Do you know which substance can be added to a kettle to remove the limescale?

Try adding some lemon juice or vinegar to get it nice and shiny again. Just remember to wash it out before you use it again or your tea may taste a bit funny!

ONLINE TUTORIAL WORKSHEETS

Here’s some relevant topic areas of Acids and Alkalis, Chemical Reactions and Neutralisation recommended by our Science teacher, designed to help young scientists.

See more worksheets here

TEACHER TIP

Have fun and ask lots of questions.

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IT’S COMPETITION TIME!

Share photos of your science experiment by tweeting us on Twitter, tagging us on Instagram or share your photo on our Facebook wall with the hashtag #edplacesummercamp. Every photo submitted will be in for a chance to win a Waterstones gift voucher! Terms and Conditions apply.

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THIS WEEK’S PARTNER & CONTENT CONTRIBUTOR

Science Sparks is passionate about making science fun for kids. All her activities are easy to do and use only equipment and materials commonly found around the home. Science for kids doesn’t have to be complicated and boring, it can be great fun for both children and adults. Science based activities offer endless creative learning opportunities and are a great way to spend time with your children.Check out her article about Summer Camp here.

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