Oh, Say Can You C? for 4 th grade

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) pencils 6 packs of markers

Location of All Materials Drawer 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 Content 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 1 Step 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 1 Step 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 1 Step 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 , the sum is 30, the average would be 30 divided by 5, the number of numbers you added. Therefore the average is 6.)