External Video
What is Photosynthesis?
Subtitle
Learn about photosynthesis and how plants use it to feed the planet.
Topic
Learn and Explore
ARS in Your Pizza
Great pizza needs great ingredients! Did you know that two of those were developed by ARS?
The oblong-shaped Roma (or "plum") tomato was developed in 1955 in Beltsville, MD, by ARS scientist William Porte. It was bred from the San Marzano and Red Top varieties to resist wilt and pests and grow well in different climates. But it also has a heavy, fleshy outer wall that makes it perfect for making sauces for pizza and spaghetti. And it contains lycopene, a nutrient with anticancer properties.
Mozzarella cheese is gooey and tasty topping for pizza, but it adds fat. ARS scientists in Wyndmoor, PA, invented a technology for making lower-fat mozzarella cheese that retains its stretchy, meltable texture and delicious flavor. They did this by modifying the network of the milk protein casein. The cheese has been widely used in school lunch programs since 1995.
Topic
Learn and Explore
Can Baby Food Affect Your Health As An Adult?
Do you ever wonder what the future holds? No, we’re not talking about staring into crystal balls or reading tea leaves. A scientist in Houston, TX, has stumbled onto the answer of how what you eat at certain stages of life may determine your future health, and it’s call epigenetics.
Robert Waterland, professor of pediatrics-nutrition at the ARS Children’s Nutrition Research Center at Baylor College of Medicine, found a naturally occurring process in which DNA molecules are modified in ways that affect gene expression – including genes that regulate the body’s ability to use sugar. This premature epigenetic process may help explain how overnutrition during infancy increases the risk of diabetes later in life.
Waterland said we still have a lot to learn about these complex processes, but one promising insight is that this might present opportunities for pharmacological interventions to slow or even reverse epigenetic aging, if we can understand it.
Want to learn more? Read "Infant Overnutrition May Lead to Health Problems Later in Life".
Topic
Learn and ExploreAppendix A: Resource Material
Saline and Alkali Soils
Saline and alkali soils have excessive levels of soluble salts, consisting mainly of sodium, calcium, magnesium, chloride, and sulfate and secondarily of potassium, bicarbonate, carbonate, nitrate, and boron. Soluble salts in the soil water (soil solution) can be high enough to negatively affect plant growth.
Saline and alkali soils are common in arid and semi-arid parts of the world. Low precipitation and low soil permeability in arid ecosystems contribute to the buildup of salts in the soil that would be leached by water down to deeper soil layers below the plant root zone.
Excess levels of salts in the soil root zone limit the ability of plant roots to absorb soil water. Water flows osmotically from low salt concentration to higher salt concentration. Roots uptake water osmotically by having a higher salt concentration than the surrounding soil water pool. Saline and alkali soils reverse the osmotic potential of plant roots and soil water.
One agricultural solution to improve salt effected soils is to “leach” the salts down deep into the soil using a lot of water. By leaching the salts below the root zone, plants can grow normally; but not all salts are equally mobile in water. Table salt is more soluble in water than baking soda because of the difference in polarity, bond types, and compound size.
The Plant Growth and Osmotic Potential project was brought to you by the Great Basin Rangelands Research Unit in Reno, NV.
Topic
ProjectsPlant Growth and Osmotic Potential
Water is a critical element for plant growth. All water used by land plants is absorbed from the soil by roots through osmosis. Osmosis is the movement of a solvent (e.g.water) across a semipermeable membrane from low solute (e.g.salt) concentration towards higher solute concentration. Excess levels of salts in soils makes soil water solute concentrations higher than in the plant root cells. This can limit plant water uptake, making it harder for plants to grow. (See Appendix A for more information)
About the Experiment
For this experiment, we’re going to test the effect that high salt soil concentrations have on plant growth and root development.
 |
Details
|
 |
|
 |
|
What You'll Need
- 7 clear plastic cups (Solo cups)
- 7 non-clear plastic cups
- Potting soil (small bag)
- Wheatgrass or cat grass seed (250 seeds, can be found online or at local pet store)
- Salt
- Baking soda
- Measuring spoons
- Drill & small bit
When using table salt (sodium chloride) and baking soda (sodium bicarbonate) to create saline and alkali soils, you can observe the germination and growth of grass leaves at increasing levels of salt and ph. Then you can treat the salt/alkali effected soils with "leaching" and observe plant growth.
Let's Do This!
1. Drill 3 small holes in 7 clear plastic cups. Have an adult help with this step for safety.
2. Fill 1 clear cup (with holes) with soil 1” from top of cup and place cup inside non-clear cup (without holes).
Pour ½ cup of water into the soil cup and allow to absorb. Pour another ½ cup of water into the soil cup.
Place 30 grass seeds on top of the wetted soil and cover with 1/8” of new soil and gently wet. Make sure seeds are covered with soil (Label cup “Control”).
3. Fill 3 clear cups (with holes) with soil 1” from top. Add 1 teaspoon of salt to the soil of 1 cup (label cup “salt 1”). Add 1 tablespoon of salt to the 2nd cup (label cup “salt 2”). Add 3 tablespoons of salt to the 3rd cup (label cup “salt 3”).
Place each cup in a non-clear cup (no holes) and add ½ cup of water to each and let absorb. Add another ½ cup of water.
Place 30 grass seeds in each cup and cover with 1/8” of new soil and moisten new soil. Make sure seeds are covered with soil (Image 2).
4. Fill 3 clear cups (with holes) ¼ full with soil. Add 1 tablespoon of baking soda to 1st cup and add more soil to fill cup 1” from the top. Hold your hand over the cup so soil does not spill and shake the cup to mix the baking soda with the soil (label cup “alkali 1”).
Add 2 tablespoons of baking soda to the 2nd cup and fill with soil 1" from top. Again, with hand over cup, shake to mix baking soda and soil (label cup “alkali 2”).
Add ½ cup of baking soda to the 3rd cup, fill with soil 1" from top and shake to mix (label cup “alkali 3”).
Place each cup in a non-clear cup (no holes). Add ½ cup of water to each and let absorb, then add another ½ cup of water. Place 30 grass seeds in each cup and cover with 1/8" of new soil and moisten new soil. Make sure seeds are covered with soil.
5. Let grass germinate and grow for 1 week.
Let’s Look At The Results!
After 1 week count the number of plants in each cup and measure the tallest blades of grass in each cup. Record the numbers for each on the data sheet. Remove the clear cups and observe root growth.
After 1 week, remove “salt 2” and “alkali 2” clear cups from red cups and place in the sink or outside (where water can drain) and slowly pour 6 cups of water through each, making sure to not over-fill (pour ½ cup at a time and let drain).
Observe which cups drains fastest (alkali soils have poor drainage). Make sure seeds are still covered with soil (add some on top if necessary) and let them grow for 1 more week.
After 1 week (2 weeks total) observe if “leached” cups now have plants that are growing. Did leaching help the same for saline vs. alkali soils?
After 2 weeks, measure the height of plants in each cup and record the results. Again, observe the roots and record observations on the data sheet.
Summarize your data and observations.
- Why did plants grow or not grow in each cup?
- What effect did leaching have on plant growth and why?
- Did leaching work on both salt and baking soda equally and why?
Topic
ProjectsEat Fish! Which Fish? That Fish! Go Fish!
For a healthy heart, the American Heart Association and the Dietary Guidelines for Americans recommends eating two, 3.5 oz servings of fish per week. Questions like “Why? Which fish?” immediately come to mind. Also, “Is wild-caught fish better than farmed?”
Several studies have shown that eating fish reduces risk of heart disease. Fish is an excellent source of protein and many species are also rich in omega-3 fatty acids, particularly the long chain omega-3's EPA and DHA.
USDA scientists at the Grand Forks Human Nutrition Research Center are studying ways to lower the cost of farming fish while improving omega 3 content and fillet quality. To find out the nutrients in different fish or create a personal eating plan, the USDA provides a free interactive tool called SuperTracker.
Read this article to learn more.
Topic
AnimalsThe Dirty vs Clean Hand Challenge
We all know having clean hands is really important, right?
Well, you may think your hands are clean but how clean are they? Grab some bread and take the dirty/clean hand challenge to find out.
External Video
Hand Washing Experiment Update
Subtitle
As promised, we did the hand washing experiment too. Our results were surprising!
Topic
Projects
Nutrition experts Dr. Patrice Armstrong and Colleen Sideck, from the National Agricultural Library's Food and Human Nutrition Information Center, answer questions and provide tips and resources for eating better and maintaining a healthy diet.
What should I do to stay healthy?
When we think about our overall health and wellness, nutrition and exercise are key lifestyle factors, along with other factors such as sleep and stress management. Nutrition and exercise help to keep the body healthy and recover when you are not feeling your best. We understand that it can be challenging to start and stick with healthy habits over time, and tools like food and fitness trackers can help with staying accountable. Apps that monitor your progress over time and provide reminders to move, drink water, or track your intake may especially be helpful. Remember, starting with a few small changes can make it easier to meet your goals than making lots of changes at once. For example, you could start increasing your physical activity by taking the stairs instead of the elevator or walking for the first 10 minutes of your lunch break. Or, for example, you could start improving your diet by swapping your usual mid-afternoon chocolate for a piece of fruit.
Knowing the benefits of eating healthy can help to maintain motivation. By eating healthy, you may be able to reduce your risk of developing certain health conditions in the future. Your nutrition and what you eat can help with prevention of heart disease, type 2 diabetes, osteoporosis, and certain cancers. If you have already been diagnosed, you may be able to use nutrition to manage your condition. Nutrition also provides short-term benefits! By eating healthy, your body and mind might feel better since they are receiving the nutrients that they need to function. This could help you as you move through your day.
I have been trying to lose weight, but it is hard. Do you have tips for helping me meet my weight loss goals? (Patrice)
It can be challenging to manage your weight during a pandemic when we are at home and our lifestyles have changed. Everyone has different calorie needs based on their height, build, and weight goals. You can use a meal planner to create a basic healthy eating plan or find sample meal plans for certain calorie goals. You can also find articles on topics including portion sizes and calories, plus tools including food diaries, trackers, and apps. For a weight loss plan and meal ideas that consider your preferences and needs, we suggest working with a registered dietitian.
Can you recommend an app or tool for tracking my diet? (Colleen)
Technology can be helpful in supporting healthy eating habits. There are many apps online that can help you plan menus, purchase foods, store foods safely, create recipes, and incorporate other wellness habits such as exercise, sleep, drinking water, and mindful eating habits. When selecting an app, it is recommended to check the source of the content in the app. Many of today’s apps use content from USDA’s FoodData Central to calculate the calories and nutrients in the foods that you are eating. Today’s apps can also provide free and credible resources to help you make informed decisions about your diet.
Are there certain ages at which a body’s metabolism slows down? (Colleen)
As we age, the body naturally loses muscle mass through a process called sarcopenia, and we also may lose muscle from being less active. This loss of muscle can impact your metabolism. The good thing is that regular exercise can help us to maintain strength and muscle. Work to find an exercise routine that you enjoy and can stick with over time. You want your routine to meet your personal needs, and it may look different than what your friends or family do. To help stay on track, you could use fitness trackers or calendars to help with motivation. If you are new to exercise or have health conditions, be sure to talk to your doctor before starting a new fitness plan.
I am trying to learn what nutrients are in my food so I can eat healthier but it’s hard to find a list of nutrients that are in common foods. What do you suggest? (Patrice)
We would recommend first starting with evaluating your diet. Perhaps, you can schedule an appointment with your doctor or a registered dietitian to see where you may be deficient in those essential micro or macronutrients. Then, once you determine your calorie and nutrient needs based on your age, size, gender and activity level. There are resources online to support you in creating a well-balanced diet. For example, In Nutrition.gov’s What’s in Food section, you can find resources on compounds that are present in common foods, including carbohydrates, fats, proteins, vitamins and minerals, phytonutrients, fiber, salt and sodium, and food additives and compounds. the ARS nutrient database, FoodData Central, which is used by researchers and professionals to see what nutrients and compounds are in foods. It can also help you to understand factors that influence variability in nutrient content, like genetics and environment. You can search a food to see its nutrition content including calories, fiber, vitamins, minerals, caffeine, and more.
My friend gives her daughter candy for doing special chores around the house. Is having candy on occasion a bad thing? (Patrice)
Candy contains added sugars, which are sugars that are not naturally present in the food and are added during processing. Added sugars contain calories but lack other helpful nutrients like vitamins, minerals, or fiber. The Nutrition Facts Label was recently updated to include added sugars, and you can use it a tool to make healthy food choices.
Should I be worried about the sugar in fruit? (Colleen)
We touched on sugars a little bit when answering the previous question about candy. Candy is a food with added sugar, but fruit is different because the sugar it contains is naturally present as part of the growing process. Fruit also contains healthful nutrients, like vitamins, minerals, and fiber. Fruit can fit into a balanced diet and can be prepared in many flavorful ways.
My doctor says I need to cut back on carbs (too much sugar). I heard overnight oats are healthy for you, but oats seem high in carbs. Should I cut down on my overnight oats? (Colleen)
Some carbohydrates are needed by the brain and body as part of a healthy diet, but for people with certain health conditions or risks, it may be indicated to decrease the amount that you eat. We do not know your specific health needs, and we suggest that you work with your doctor or a registered dietitian to determine what goal is right for you. However, in general, when choosing carbohydrates to eat, it can help to choose types that provide nutrients like vitamins, minerals, protein, and fiber. Fruits, vegetables, beans or legumes, whole grains, and dairy products are examples of carbohydrates that also provide some of these nutrients that the body needs. Overnight oats typically contain oatmeal (a whole grain) and milk (dairy) and sometimes fruit, and they can be a healthy choice.
Which has more cholesterol, donuts or bagels? (Patrice)
Eating less dietary cholesterol can be part of a heart-healthy diet. Cholesterol is found in foods from animal sources, like meat and cheese, and it is also naturally made by the body. When we’re dealing with cholesterol from food sources, that is referred to as “dietary cholesterol.” There are many different recipes that can be used to make foods like donuts and bagels. Whether or not the food contains dietary cholesterol depends on if and what amounts of animal products (such as egg yolks, milk, or butter) are used in the recipe.
I don’t eat meat. How can I get enough protein? (Patrice)
There are many sources of protein other than meat that you can incorporate into your diet. If you eat seafood, fish and shellfish are options. Dairy and eggs may also be options. For people who are vegan, you can choose pulses, which include beans, dry peas, and lentils. You can also get protein from tofu, tempeh, seitan, and soy. Your individual protein needs will vary based on your age, activity level, and if you have a pre-existing health condition. You can also use calculators online to determine how much protein you should eat each daily.
Does my child have to drink milk to get calcium? (Colleen)
If your child does not drink milk, do not worry. Milk is not the only food or beverage that provides calcium. Many alternative beverages such as those containing soy, almond, oat and cashew are fortified with calcium, or have calcium added. You can also find calcium in foods like yogurt, sardines, fortified tofu, fortified breakfast cereals, kale, and broccoli.
What type of activities do you recommend for kids? My kids have been spending lots of time at home, and I am looking for things to keep them busy. (Colleen)
Definitely! Let’s first talk about how there are both fitness activities, such as yoga and dance videos, in addition to craft activities such as making holiday-themed decorations and preparing recipes based on storybook tales. There are also apps and websites that support education while keeping your child busy and engaged both on our websites and elsewhere.
Nutrition.gov’s Kids’ Corner page is the place to go for games, videos, word searches, crossword puzzles, coloring sheets, and other activities that your kids can do at home. Some activities can be done online. Other activities, like the worksheets, are printable. Whatever method is right for your family, know that your child will learn valuable lessons in making healthy food choices and keeping food safe to eat. We also have physical activity resources for kids, including videos for yoga, dance, and other activities that get kids moving. Find them on our Exercise Examples and Videos page. To any teachers who may be listening, these resources also make great additions to classroom lessons.
My son is a really picky eater. How can I get him to eat healthy and try more foods? (Patrice)
Every child has different preferences when it comes to food, and it can take time to get used to new flavors. One way to encourage your child to try new foods is through mealtime activities. For example, you could have them choose a new fruit to try at the store or stir together ingredients for homemade whole grain bread. You could also hide vegetables in meals that they like, such as mixing pumpkin in your mac and cheese or hiding spinach in your afternoon smoothie. If you have concerns about your child’s nutrition, it may also be helpful to talk to your pediatrician. Your pediatrician will be able to determine whether your son is getting the nutrients that they need and offer personalized suggestions for your child. They can also provide much needed reassurance to parents!
I want my family to eat better. How do I make the foods we like and still eat healthy? (Patrice)
Great question. We know food is an important part of culture and traditions, plus it is nice to be able to enjoy a meal and conversation as a family! There are many resources available that can show you how to cook your favorite ingredients in healthier ways, such as adding herbs to a recipe instead of salt. Or, when baking, substituting applesauce in place of oil. Baking or roasting versus frying may also be another method you might incorporate for your meals.
Our Meal Prep and Cooking Tips page on Nutrition.gov offers resources on how to cook your favorite ingredients in healthier ways. We would also encourage you to check out our recipes for a variety of family-friendly meals and snacks, including fried rice, enchiladas, pancakes, popsicles, healthy cookies, and so much more!
Do you have healthy eating resources and recipes for traditional foods that my family likes? (Colleen)
Traditional foods, flavors, and cuisines offer a variety of healthy choices. We currently have recipes for pupusas, enchiladas, yucca, fried rice, stir fries, and more. There are also more examples of traditional recipes for Latino, Asian, African American, and American Indian cuisines. We are working to add even more recipes, so we welcome you to submit suggestions on our Contact Us page! There may be some listeners who are looking for Spanish language nutrition resources. You click the “Español” toggle at the top right corner of all pages to view available healthy eating materials in Spanish.
The listeners who asked this question did not share details about their traditions and culture, so that makes it tough to provide specific recommendations. To receive nutrition tips that consider your cultural and personal preferences, we suggest working with a registered dietitian.
What are some tasty, and healthy ingredients to put in a morning energy shake?
You can add many vegetables and fruits in your smoothie, including spinach, kale, apples, and bananas. If you have any health conditions, it is important to consult your doctor or a registered dietitian to help customize a smoothly that is suitable for you.
I often hear that carbohydrates are bad for your diet. Is that true?
Thank you for your question. The body and brain need carbohydrates to function properly. There are many sources of carbohydrates, like fruits, vegetables, beans, dairy and whole grains, that provide important nutrients like vitamins, minerals, and fiber.
Additional Resources
- List of foods and beverages with calcium and how calcium helps the body
- Nutrition Facts Label Information
- Food Data Central
- Meal prep and cooking tips
- Activities for your children
Topic
Nutrition CornerAgLab: Science for a Growing Mind
Welcome to AgLab, ARS’s website dedicated to students, educators, and parents who are interested in exploring the intersection of where food meets science.
The Agricultural Research Service is the premier agricultural research agency in the world. We find solutions to agricultural problems that affect Americans every day, from field to table.
Geared toward k-12 students with an interest in food and science, AgLab offers a variety of content to promote a greater understanding of how agricultural research is helping meet the food, fiber, feed and fuel needs of a growing world population while also safeguarding our environment and natural resources.
Check back often to view new AgLab content, including videos, nutrition tips, science projects, apps and more.
Topic
About UsSoil Amendment Experiments
About the Experiment
Plants need suitable conditions to thrive and soil provides a physical medium for seeds to germinate and allow roots to explore, thereby anchoring the plant in place. Water and nutrients are needed along with an abundant supply of sunlight! There are two main sources of nutrient applications to soil – 1) inorganic fertilizers that can be purchased commercially and 2) organic amendments such as composted materials and discarded, natural foods. This experiment will focus on organic amendments.
Let's Find Out How With This Project
|
Details
|
|
|
|
|
What You'll Need
- A suitable space to grow your plants for up to 6 weeks. This can be a table next to a large window receiving lots of sunlight or a flat area outdoors that won't get disturbed and has plenty of sunshine.
- Containers to grow your plants. These can be of different sizes and shapes, but should be sturdy enough to hold moist soil for the duration of the experiment. They could be as large as 5-gallon buckets or as small as 6-ounce plastic drinking cups. Containers should have drainage holes on the bottom to allow excess water to drain from the soil. You will also need a large cookie sheet or similar item to hold the cups as well as the drained water.
- Seeds. Consider various broadleaves such as turnip, sunflower, or beans or some common grasses like wheat or corn. You may even consider radish, spinach, or collards, which are short-duration vegetables that can mature and be edible within 6 weeks.
- Soil. Enough to fill all containers. Any soil can be used, including soil from your garden, dirt from your backyard, or sand.
- Organic materials to amend the soil. Dried grass clippings, dried leaves, used coffee grains, egg shells, compost, cardboard egg containers, leftover fruits and vegetables. Any of these will do.
- Spreadsheet to track progress of the experiment.
Let's Do This!
1. Choose 1-3 organic amendments. You will also have a "soil only" plant, which will be the control experiment. For each experiment, you'll need three plant test subjects. For example, if you choose coffee grains, eggshells, and grass clippings, you'll need a total of 12 test subjects – three for each amendment and three for the control. You can also add a fifth test subject that includes a mixture of all three amendments.
2. Individually mix each organic amendment (generally about 2% of the soil weight should be of the amendment) with soil thoroughly and weigh out the desired amount of amended soil into the three containers (make sure you label the containers!). The containers should be 3/4th filled with the amended soil. Add soil without an amendment to the three control containers.
3. Place seeds into a small indentation of the soil in each container. Note that some seeds may not germinate or may die for various reasons. Therefore, plant 5-6 seeds for each container and thin to 3 plants per container a few days after emergence.
4. Add water to each container and allow excess water to drain through holes at the bottom.
- Note for more controlled experiments: You can determine the water-holding capacity of the soil before planting seeds by soaking the containers with full water and allowing ½" of water to accumulate in a tray in which the containers are held. After 1 day of soaking, weigh the containers and this will be the maximum weight of the container plus soil. If you weigh the container without soil and the weight of the container plus dry soil, you will be able to calculate with accuracy the soil water content at saturation. Plants often perform best when soil is maintained between 40 and 80% of saturation. As an example, if the container weighs 10 g and the dry soil is 500 g, then the total weight after soaking at saturation may be 660 g.
5. Place the containers in a room temperature environment not exposed to direct sunlight until seedlings emerge. Once most seedlings emerge, evaluate the need to thin out excess plants and then place in more direct sunlight for allowing plants to grow vigorously.
6. Water plants according to their needs. This could be once per week initially when plants are small to once per day when plants are large and growth conditions are most favorable. The plants will wilt and die if not enough water or too much water is provided.
Measurements to evaluate the experiment
7. There are a variety of measurements you can make to evaluate the results of the experiment. Create a spreadsheet and make a column for each container in the experiment and each row or line of information can be an observation that has a response recorded for each experimental unit
8. Take weekly photos to create a visual documentary of plant growth and changes
9. Simple qualitative measures might include color of the plant, tendency to wilt, stopped growing, has odd-shaped leaves, attracted by insects, etc. Simple quantitative measures might include days to emergence, number of seedlings emerged and height from soil at 1 week, 2 weeks, etc. up to the end of the experiment. Size of leaves could be determined periodically. Sensor measurements of leaf color can provide a quantitative evaluation of plant health.
10. After 6 weeks, consider whether sufficient evaluations have been made, or if plants should be evaluated further for product tasting (in the case of leafy greens), bulb growth (in the case of radish or turnip), or cutting plants at soil level and making measurement of wet weight and/or dry weight (after placing cut plants separated by container into paper bags and placed in direct sunlight to dry for several days or in an oven at 150 F for a day or until dry.
What did you learn?
- Which amendment produced the most growth potential? Why do you think some amendments are better than others?
- How did the different plants with amendments compare to the control plants?
- Did the plants taste different?
- Where there any color or size differences among the plants?
- Which plants grew fastest, which were the slowest growing?
- Do you think positioning of the plants and their distance to sunlight mattered?
- Which week had the most growth for the bulk of the plants?
- Do you think the experiment results would be different if another seed type was used?
- Could you grow other plants with organic amendments alone?
- Would you like to be a life-long gardener or farmer? Why/why not?