Oh, Say Can You C?for 4th grade

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Activity Guide

• Challenge: Discuss the challenge (5-10 minutes)• Generate Ideas and Multiple Perspectives (instructor choice)• Research and Revise (and Test Your Mettle)

– Activity 1: Discuss vitamin C (sources and why it is important to our bodies) (5-10 minutes)

– Activity 2: Measure the vitamin C content of three different juices (20-25 minutes to complete tests and worksheet)

• Go Public: Revisit the challenge (instructor choice)

Teacher Tips• Make sure to fill the cups with indicator solution to the same level.

– Some of the cups have a black line on them. Disregard this line.– Fill the cups to the indention at the bottom of the cup. – You will have less than ¼” of indicator solution.

• The juice cups should be filled to the same line. They do not need to be as consistent because they are not the indicator.

• It is important that the students wear goggles and vinyl gloves. The dye is hard to remove.

• Students should use the droppers only to drop juice in the indicator solution WITHOUT touching the indicator solution.

• The craft sticks are to be used ONLY to stir the indicator solution into the juice. They should NOT touch the indicator solution.

• Each group of students at each table will test all three types of juice. – They will record results and create a graph– This lab is meant for 4 students working at each of 6 tables. More students can

work together if needed.

Teacher prep• For 6 tables with 3-5 students at each table

– Fill juice cups:• 3 different juices for each station - Orange, white grape, apple (or other available juices as

long as you have 3 different juices – not red or purple color)• You will need 6 cups with orange juice, 6 cups with grape juice and 6 cups with apple juice.

Fill the cups to the lower indentation near the bottom of the clear cups. You will have about ¼” of juice in each cup. You will end up with 18 cups of juice.

– Fill indicator solution cups• Add indicator solution to 18 more cups.• Fill to the lower indentation near the bottom of the cup. You will have about ¼” of

solution.

– Assemble materials from the next page.• You can place the cups on the 6 tables or let the students get them from you.

– One cup of each juice on each table– 3 cups of indicator solution on each table.

• Place the following in each of 6 bins for each table of 3-4 students

– 3 droppers– 3 wooden craft sticks– 1 copy of Vitamin C Data Chart– 1 piece of white paper– 1 marker

Materials• Pre-mixed 2,6 dichlorindiphenol solution

(blue, clearly marked “2,6 dichloroindipheonl Solution)

• 3 different bottles of fruit juice (not red or purple)

• 36 clear plastic cups• 18 eye droppers• 18 wooden craft sticks• 6 sheets of copy paper• 6 copies of Vitamin C Data Chart – stored

in lower left filing drawer in mechanical room

• 24 safety goggles (enough for everyone)• 24 pairs of vinyl gloves (enough for

everyone)• 24-30 pencils• 6 packs of markers

Location of All MaterialsDrawer 2a1 contents:• Droppers• Mechanical pencils• Wooden craft sticks (tongue depressors)• Water soluble markers, variety of colors

Drawer 2a2 contents:• White copy paper

Drawer 2a3 contents:• Clear plastic cups• Bottles of 2, 6 dichloro indophenol

(vitamin C indicator solution)• Disposable vinyl gloves

Drawer 2a4 contents:• White grape juice• Pineapple juice• Orange juice• Apple juice• Pear juice

Goggles are located in Drawer 5b4

2a1

2a2

2a3

2a4

Worksheet – Vitamin C Data Chart

Challenge• Your school is going to install a new drink machine. The principal

has asked you to select three of the healthiest (low sugar, high vitamin C) drinks from the following list.– Orange “sports” drink– Orange “energy” drink – Orange juice– “Low” sugar orange juice– Orange diet soda– Citrus flavored green tea (in a bottle)

• You must use chemical or physical tests to determine vitamin C content NOT the label or a nutrient guide book or the internet.

• You can use the label to determine and compare sugar content.

Guiding question

• How can we use chemical substances to determine the Vitamin C content of fruit juice?– What is vitamin C?

• List several good sources of vitamin C (food).• What does vitamin C do for our bodies?

– What is an indicator solution?• What physical change in the indicator solution will indicate

the presence of Vitamin C?• What is the difference in change within the indicator

solution for a good source of vitamin C and a poor source of vitamin C?

– What does “physical change” mean?

Activity 1 – Discuss Vitamin C (5-10 minutes)• Vitamin C is a water-soluble vitamin that is necessary for normal growth and development.

– Water-soluble vitamins dissolve in water. – Leftover amounts of the vitamin leave the body through the urine. That means you need a continuous supply of such

vitamins in your diet.– The body is not able to make vitamin C on its own, and it does not store vitamin C. It is therefore important to include

plenty of vitamin C-containing foods in your daily diet.– Cooking vitamin C-rich foods or storing them for a long period of time can reduce the vitamin C content. Microwaving

and steaming vitamin C-rich foods may reduce cooking losses. The best food sources of vitamin C are uncooked or raw fruits and vegetables.

• Function– Vitamin C is needed for the growth and repair of tissues in all parts of your body. It is used to:

• Form an important protein used to make skin, tendons, ligaments, and blood vessels• Heal wounds and form scar tissue• Repair and maintain cartilage, bones, and teeth

• Sources:– Fruits with the highest sources of vitamin C include:

• Cantaloupe• Citrus fruits and juices, such as orange and grapefruit• Kiwi fruit• Mango• Papaya• Pineapple• Strawberries, raspberries, blueberries, cranberries• Watermelon

– Vegetables with the highest sources of vitamin C include:• Broccoli, Brussels sprouts, cauliflower• Green and red peppers• Spinach, cabbage, turnip greens, and other leafy greens• Sweet and white potatoes• Tomatoes and tomato juice• Winter squash

Activity 2 – Test Vitamin C Content20-25 minutes

WARNING!!!!• Do not drink the indicator solution!!!

• Do not drink the fruit juice!!!

• If you get the indicator solution on your skin, rinse with cool water. It may temporarily stain your skin.

Safety!!!

• Everyone should wear vinyl gloves throughout the experiment.

• Everyone should wear goggles throughout the experiment.

Set up your work station• Put a sheet of white paper on your work station.• Write the names of the fruit juice on a piece of

copy paper.

Obtain juice and indicator solution• Get three small cups of fruit juice from your

teacher. You should have 3 different kinds of juice.• Get three small cups of indicator solution from

your teacher.

• If your teacher has prepared them, these cups may already be on the table!

Prepare for testing

• Put the juice cups in the back row behind their appropriate label.

• Place one cup of indicator solution in front of each type of juice.

Record the properties of the liquid in each cup

• What color is the indicator solution?• Is it clear or cloudy?• What color is each juice?• Are they clear or cloudy?• Record in Vitamin C Data Chart.

General Guidelines for Lab Experiment• Set 1 dropper in each of the fruit juice cups.– Use the droppers ONLY in the fruit juice!– Do not stir the indicator solution with the dropper.

• Set 1 craft stick in each cup of indicator solution.– Use the craft sticks in the indicator solution ONLY!!!!

• Do not mix the droppers and craft sticks!!!!!– If you mix the two tools, you will alter the results of

the experiment by contaminating the juice and indicator solution.

Test for Vitamin C Content – Juice 1Step 1

• Use an eye dropper to drip one drop of juice 1 into a container of indicator solution. – Squeeze the bulb on the dropper. Place in juice 1.– Let go of the bulb and draw up the juice.

• Remember to return the dropper to the same juice cup.You decide which juice is Juice 1, Juice 2, and Juice 3. Be sure to record this.

Test for Vitamin C Content – juice 1Step 2

• Stir the solution carefully with the craft stick.• Remember to keep the craft stick in the indicator

solution cup.

Test for Vitamin C Content – Juice 1Step 3

• Keep dropping juice, one drop at a time, counting each drop and stirring after each drop until the solution turns clear pink.

• Count the number of drops it takes until the solution turns from blue to clear, light pink. (A very pale pink color is OK.)

Record the number of drops of juice 1 it took to turn the solution clear in your Vitamin C Data

Chart.

Test for Vitamin C content – Juice 2

• Use an eye dropper to drip one drop of juice 2 into a container of indicator solution.

• Stir the solution carefully with the craft stick.• Keep dropping juice, counting and stirring

until the solution turns clear, light pink.• Count the number of drops it takes until the

solution turns from blue to pink.• Record in your Vitamin C data chart.

Test for Vitamin C content – Juice 3

• Use an eye dropper to drip one drop of juice 3 into a container of indicator solution.

• Stir the solution carefully with the craft stick.• Keep dropping juice, counting and stirring

until the solution turns clear, light pink.• Count the number of drops it takes until the

solution turns from blue to pink.• Record in your Vitamin C Data Chart.

Note the appearance of the indicator solution.

• Record the appearance of the indicator solution with each of the fruit juices added to it in your Vitamin C Data Chart.

• Is the indicator solution truly clear? Or cloudy?• Does it have color?

Compare Vitamin C Content with other groups in the Class

• Discuss vitamin C content of each juice across the class.

• Calculate the average number of drops of juice necessary to turn the juice clear, light pink.– Were there variations between groups for the

same type of juice?– If variations were present, why?– What could you do to minimize variations?

What does all this mean?

• The fewer the number of drops of juice needed to turn the indicator solution clear, the higher the Vitamin C content of the juice.

• Which juice had the greatest amount of Vitamin C?

The directions tell us not to use purple or red juice.

• Why do you think this is?

Does this mean that these fruits (apple, grape, and orange)

really have vitamin C?

• After completing your experiment, ask your teacher to show the labels of each of the juices.

• Did any of them have added vitamin C?• Where could you get fruit juice without added

vitamin C?

What physical characteristics of the indicator solution demonstrated Vitamin C content?

• What does Vitamin C do for our bodies?• Name some good sources of vitamin C.• Define indicator solution.

Go Public – Revisit Challenge (5-10 minutes)

• Your school is going to install a new drink machine. The principal has asked you to select three of the healthiest (low sugar, high vitamin C) drinks from the following list.– Orange “sports” drink– Orange “energy” drink – Orange juice– “Low” sugar orange juice– Orange diet soda– Citrus flavored green tea (in a bottle)

• You must use chemical or physical tests to determine vitamin C content NOT the label or a nutrient guide book or the internet.

• You can use the label to determine and compare sugar content.

Vocabulary

• Chemical property – the traits of an object that make it unique. Its building blocks, called atoms are arranged differently for each chemical.

• Physical property – properties that you can see – color, size, shape, texture, etc.• Physical change – a change in physical property. You can see this type of change.

The substance does not turn into another substance.• Chemical change – change that occurs at the molecular level. Creates a new

substance. The atoms are arranged differently. You may not be able to see a chemical change.

• Indicator solution – liquid that undergoes a change in physical change to indicate a chemical change.

• Vitamin C – ascorbic acid. An essential nutrient important to skin health, immunity, and absorption of other vitamins.

• Average – a mathematical term meaning to add several numbers together and divide by the quantity of numbers that you added. (If you add 5+4+7+9+5, the sum is 30, the average would be 30 divided by 5, the number of numbers you added. Therefore the average is 6.)