this area addresses ph among different characteristics of ... · half fill a cup with 100% lemon...

This area addresses pH among different characteristics of solutions. It will be interesting for students to classify a variety of solutions into acids and bases by using the characteristics of the solutions. Students observe changes after placing indicators into a variety of solutions and classify them as acidic and alkaline. Students learn how the characteristics of the solution change when acidic and alkaline solutions are mixed. Students are to conceive and explain examples of how acidic and alkaline solutions are used in everyday life.

The grade 5 English science unit, Acids and Bases, meets the academic content standards set in the Korean curriculum, which state students should:

a) Observe changes after placing indicators into a variety of solutions and then classify the solutions as acids and bases.

b) Recognize the characteristics of acid and base solutions.

c) Be aware through color change of indicators that acidity and alkalinity weaken when the two types of solutions are mixed.

d) Be able to find examples in everyday life in which the characteristics of a solution change when acidic and alkaline solutions are mixed.

What do I need to do? You will need a lemon, 100% lemon juice, baking soda, ½ teaspoon, a peach, a plate, a knife, a cup, and CC lemon.

Some useful information

1. Cut the lemon and peach so that your entire group gets a piece. Suck the juices and notice how they taste. Complete the chart.

2. Half fill a cup with 100% lemon juice. Fill the remainder of the cup with water. Add ½ teaspoon of baking soda. Have a small sip.

3. Pour some CC lemon into the cup. Have a drink. Compare the taste to the lemon soda you made in step 2.

What happened?

What did I learn?

1. Why do lemons taste sour?

__________________________________________________________________________________________________________________

2. What makes peaches taste sweeter than lemons?

__________________________________________________________________________________________________________________

Complete the charts. Draw a picture to show what happened in step 2.

Lemons taste very sour because they have a lot of acid in the juice. The juice of other fruits, such as peaches, also has a little acid, but they have a lot of sugar which makes them taste sweeter.

100% lemon juice drinks are also very sour due to the acid. However, most fizzy drinks contain a lot of sugar which gives them a sweeter taste.

Fruit Lemon Peach Taste

Drink 100% lemon soda CC Lemon Taste

1

What do I need to do? You will need blueberry juice, scissors, cotton material, a paintbrush, water, gloves, baking soda, laundry detergent, dishwashing detergent, soap, and a bowl.


1. Cut the cotton material into 4 pieces. Use the paintbrush to paint a picture with the blueberry juice.

2. Let the cotton material dry a little. Then, try to wash out the blueberry juice stains using just water.

3. Put on gloves. Use a different cleaning agent on each of the cotton pieces. See if they can remove any remaining stains.

What happened?

What did I learn?

1. Compare the taste of acids to bases.

__________________________________________________________________________________________________________________

2. How are bases often used in your house?

__________________________________________________________________________________________________________________

Complete the chart.

Fruits have acids. This is why they taste sour. Lots of fruits also have a dye called tannin. Some fruits, like blueberries, have a lot of dye and won’t wash out just in water. You need to use a cleaner. There are many different types of cleaners that are used for different reasons. Some are good for cleaning dishes. Others are good for cleaning your clothes. Others are good at washing your hands. Many cleaners are the opposite of acids. They are known as bases. They have a bitter taste, but are usually not good to eat or drink.

Cleaner Observations Water Soap

Dishwashing detergent Baking soda

Laundry detergent

2

What do I need to do? You will need red litmus paper, blue litmus paper, different acid and base samples, and a well plate.


1. Pour the different samples into the well plate.

2. Dip a different strip of the red litmus paper into each sample for about one second and then remove. Note the color.

3. Dip a different strip of the blue litmus paper into each sample for about one second and then remove. Note the color.

What happened?

What did I learn?

1. What would happen if you put blue litmus paper in an acid?

__________________________________________________________________________________________________________________

2. Why should you use both red and blue litmus paper on the same sample?

__________________________________________________________________________________________________________________

Complete the chart.

Litmus paper is commonly used to show if something is an acid or a base. It comes in red and blue. You should use both of these on the same sample to find out if it is an acid or base.

Acids will turn blue litmus paper red. If you use red litmus paper in an acid, you won’t see any color change. Bases will turn red litmus paper blue. If you use blue litmus paper in a base, you won’t see any color change.

Sometimes solutions are not an acid or a base. These are called neutral. Red litmus paper stays red in them and blue litmus paper stays blue in them. This is why you should use both colors when checking to see if something is an acid or a base, because it might be neutral.

Sample Red Litmus Paper Color Blue Litmus Paper Color

3

What do I need to do? You will need red cabbage juice, different acid and base samples that are colorless, pipettes, and a well plate.


1. Pour a little of the red cabbage juice into 6 of the holes on the well plate.

2. Use a pipette to add the test samples to a different hole on the well plate containing the red cabbage juice.

3. Observe what happens. If the red cabbage juice turns pink or red, the sample is an acid. If it turns blue or green, the sample is a base. If it stays purple, it is neutral.

What happened?

What did I learn?

1. What color does red cabbage juice turn in acids and bases?

__________________________________________________________________________________________________________________

2. How are red cabbages and hydrangeas similar and different?

__________________________________________________________________________________________________________________

Complete the chart.

Red cabbages are called natural indicators. This means they can indicate or show what things are acids, bases or neutral. The juices of red cabbages turn red or pink in acids. It turns blue or green when it is added to bases. Red cabbage juice will stay purple in neutral substances.

Hydrangea flowers are also natural indicators. The flowers turn blue in acidic soils and pink in basic soils.

Sample Red Cabbage Juice Color Acid or Base?

Is this hydrangea in soil that is acidic or basic?

4

What do I need to do? You will need universal indicator paper and color chart, different acid and base samples, and a well plate.


1. Pour a little of the samples in the 6 holes in the well plate.

2. Dip a different strip of the indicator paper into each sample for about one second and then remove.

3. Compare the color with the color chart within 5 seconds.

What happened?

What did I learn?

1. Which of the samples in this experiment were strong acids? How do you know?

__________________________________________________________________________________________________________________

2. What Universal indicator colors show weak bases and strong bases?

__________________________________________________________________________________________________________________

Complete the chart.

Universal indicator paper is made by mixing different dyes that change into different colors when they touch acids and bases. There are 14 different colors that each has a pH number. These colors and numbers show how weak or strong the acids and bases are.

A pH value between 1 and 3 shows a strong acid. A pH value between 4 and 6 shows a weak acid. A pH value between 8 and 10 shows a weak base. A pH value between 11 and 14 shows a strong base. A pH value of 7 shows that the sample is neutral.

Sample Universal Indicator Color pH

5

What do I need to do? You will need universal indicator paper and color chart, different drink samples, a well plate, poster paper, and colored pencils or markers.


1. Pour a little of the drinks in the 6 holes in the well plate.

2. Dip a different strip of the indicator paper into each drink sample for about one second and then remove. Compare the color with the color chart.

3. Create a poster to warn people about the dangers of drinking acidic drinks.

What happened?

What did I learn?

1. What is tooth erosion?

__________________________________________________________________________________________________________________

2. Which drinks from this experiment will cause tooth erosion? Explain your answer.

__________________________________________________________________________________________________________________

Complete the chart.

Dentists have started to warn people about the dangers of drinking acidic drinks. They have found that acidic drinks dissolve the enamel covering of the tooth. Drinking acidic drinks over a long period of time means that the enamel disappears and the tooth starts to crumble at the edges. This is known as erosion.

What drinks should you stop drinking so that this doesn't happen to you? Dentists say that if the pH level of the drink is below 5.5, then tooth erosion will occur. The safe pH level for drinks is 5.5 and above.

Drink Universal Indicator Color pH

An example of tooth erosion. The teeth have started to break because the person drank too many acidic drinks.

6

What do I need to do? You will need white vinegar or lemon juice, an egg, a jar, chalk, a pipette, a dish, salt, a cup, and a 10 yen coin.


1. Fill a jar with white vinegar or lemon juice. Carefully put in the raw egg and observe what happens. Leave it in there for a few days.

2. Put a piece of chalk in a dish. Use a pipette to slowly add vinegar on top of the chalk.

3. Put some vinegar in a cup and a teaspoon of salt. Add the 10 yen coin. Give the cup a quick swirl and wait for 5 minutes.

What happened?

What did I learn?

1. How is acid rain made?

__________________________________________________________________________________________________________________

2. What damage does acid rain cause?

__________________________________________________________________________________________________________________

Draw pictures to show what happened.

Acid rain is made when smoke from factories and motor vehicles, such as cars, mix with the water in the air. It is the sulfur dioxide and nitrogen oxides in the smoke that helps to make the acid rain. The pH of this rain is below 5. In some cases, the pH has been lower than 2.4.

Acid rain can slowly damage things. For example, acid rain can destroy metal objects, such as bridges and cars. This is called corrosion. Acid rain also dissolves things made from limestone, such as statues and buildings. Eggshells and chalk are made from the same thing that makes up limestone.

A statue damaged by acid rain.

7

What do I need to do? You will need white vinegar, a well plate, baking soda, ½ teaspoon, scales, cups, Universal indicator paper, and pH chart.


1. Dissolve 5g of baking soda in 200mL of water.

2. Add ½ teaspoon of vinegar to each of the holes on the well plate.

3. Add the amount of baking soda solution as stated in the chart below. Use pH paper to determine the pH of the final solution.

What happened?

What did I learn?

1. What happens when you mix an acid and base together?

__________________________________________________________________________________________________________________

2. How is the concept of neutralization useful to people?

__________________________________________________________________________________________________________________

Complete the chart.

If you add the right amount of an acid to a base, you can make a neutral solution. As the acid and base react, salt and water are made. This reaction is called neutralization.

Acid + Base = Salt + Water

Understanding this concept can help people in their everyday life. For example, if you eat too much food, sometimes your stomach makes too much acid. This stomach acid can move up your esophagus and cause a bad burning feeling. If this happens, people can take medicine that is a base to help settle your stomach.

Amount of baking soda added to the vinegar. Universal Indicator Paper Color pH 0mL

2.5mL 5.0mL 7.5mL

10.0mL 12.5mL 15.0mL

8

What do I need to do? You will need white vinegar, a Ziploc bag, a tablespoon, baking soda, a paper towel, and a bucket.


1. Fill a Ziploc back with 125mL of vinegar.

2. Put 2 heaped tablespoons of baking soda on a paper towel and wrap it up.

3. Put the wrapped up paper towel into the Ziploc bag and quickly seal it up. Give it a little shake and put it in a bucket.

What happened?

What did I learn?

1. Why did the Ziploc bag explode when you mixed the acid and base together?

__________________________________________________________________________________________________________________

2. What 3 things are made when you add a carbonate to an acid?

__________________________________________________________________________________________________________________


If you add an acid to some types of bases, a gas is made. The base needs to be a carbonate for this to happen. Chalk, eggshells and limestone are all made with calcium carbonate, which is why you saw bubbles being made when you added an acid to them. Baking soda is also called sodium bicarbonate. A gas will be made when an acid is added to it, too. The gas is carbon dioxide. The equation below shows the reaction that happens;

Acid + Base (carbonate) = Salt + Water + Carbon Dioxide

When acid rain hits these statues, carbon dioxide gas is made.

9

What do I need to do? You will need baking soda, measuring cups, a tablespoon, ½ teaspoon, food coloring, olive oil, citric acid, a bowl, a spoon, a small dinosaur figure, and water.


1. Add ½ a cup of baking soda, ½ a teaspoon of water and 5 drops of food coloring to the bowl. Mix well. Then, add 2 tbs. of citric acid and mix well again.

2. Add a tbs. of olive oil and mix. Add another tbs. of olive oil and mix. Add a third tbs. of olive and mix. Use your hands to mold the mixture into an egg shape. Put in the dinosaur figure.

3. Give your dinosaur egg a little time to dry. Then, fill a bowl with water. Carefully add the egg. Observe what happens.

What happened?

What did I learn?

1. How can scientists study the inside of a fossilized dinosaur egg?

__________________________________________________________________________________________________________________

2. What do scientists need to be careful of when using acid?

__________________________________________________________________________________________________________________


Fossilized dinosaur eggs were being found in the mid 1800’s. However, people thought they were bird eggs. Scientists can now identify dinosaur eggs. Dinosaur eggs should be about the same thickness all the way around, they should be slightly curved, and the surface should be covered with little pores.

Scientists study fossilized dinosaur eggs to learn more about dinosaurs and where they lived. On rare occasions, a fossilized dinosaur in the egg can be found. One way to reach this fossilized dinosaur is to carefully dissolve the outside of the egg. Scientists do this by putting the egg in an acid bath. They have to be careful that the acid also doesn’t dissolve the fossil inside.

Fossilized dinosaur eggs.

10

this area addresses ph among different characteristics of ... · half fill a cup with 100% lemon...

Documents