During this 60–90-minute activity, children ages 8–13 explore what living things need to survive and thrive by creating and caring for a garden plot (outdoors where appropriate) or a container garden (indoors) at the program facility. The garden will be used to beautify the facility with plant life with many planting and landscaping options provided. Children will consider the requirements of living things, compare the surface conditions on Mars to those found on Earth, view images/video of a NASA Astrobiology Institute “garden” where astrobiologists are studying life under extreme conditions, and consider the similarities and differences in the type of life that would be possible on Mars as compared to their garden on Earth.
What's the Point?
- Earth and Mars have many differences and many similarities.
- Scientists have gained a great deal of information about Mars in recent years, and there is still much to learn.
- Life as we know it requires liquid water, energy, nutrients, and shelter to survive.
- Astrobiologists use life found on Earth to help them understand how life may have formed on other planets, like Mars. Some of these life forms live in what are considered by scientists to be very “extreme” environments and are referred to as “extremophiles.”
- Astrobiologists are simulating extreme conditions in special gardens/labs here on Earth in order to study possible life on Mars.
- Astrobiologists are searching for life on Mars because it appears that conditions may have been — or may currently be — suitable for life on the Red Planet.
Tips for Engaging Girls in STEM:
- Expose girls to female role models who have achieved in math and science in order to promote positive beliefs regarding women’s abilities. If possible, have female speakers share the science of astrobiology. This activity addresses this tip by providing activity pages and trading cards featuring female (and male) astrobiologists, as well as link to online resources for connecting with female scientists and role models. Suggestions and links to online video resources featuring interviews with female scientists are also included within the activity for those not able to arrange for an in-person presenter.
- Foster girls’ long-term interest in math and science by choosing activities connecting math and science to careers (don’t reinforce existing gender stereotypes, and do choose activities that spark initial curiosity about content). This activity addresses this tip by providing a topic that most people are naturally interested in learning more about — the possibility of life elsewhere in the universe — in a context that is engaging (gardening). The corresponding activity pages, trading cards, and optional scientist involvement help to address this tip by providing a range of real-world examples of female scientists in the field of astrobiology (and its associated disciplines). Specifically, the activity resources present female scientists — in their own words — describing how they became interested in math and science, how they ended up their current role (astrobiology), and their advice for children interested in pursuing a career in math and science.
- A selection of books about gardening for children.
- A selection of books about Mars, astrobiology, and extremophiles
- 2–3 pitchers or watering cans (to be controlled by an adult)
- 1 set of the NAI Extremophile Trading Cards
Facilitator’s Note: Recommended Plants and Seeds
It is important to use plants and/or seeds that are appropriate for your intended garden location (indoors or outdoors). Particular attention should be paid to the lighting, soil, and water conditions of the intended planting location. It is recommended that you research appropriate plants for your growing zone or consult a garden center/plant nursery/master gardener in your area. There are many options for your garden — it can be edible, hardy/drought tolerant (xeriscaping), flowers (for cutting), etc. Below you will find a list of recommended plants that may be suitable and readily available (seasonally) for many locations, growing zones, and gardening options.
- Vegetables (cucumber, pepper, pumpkin, etc. — annual, edible
- Herbs (basil, thyme, parsley, mint, etc.) — annual, edible
- Marigolds (flowering) – annual
- Zinnia (flowering) — annual
- Petunia (flowering) — annual
- Cosmos (flowering) — annual
- Daylilies (flowering) — perennial, zones 3–10
- Hosta (flowering) — perennial, zones 3–9
- Columbine (flowering) — perennial, zones 3–9
- Seeds (annuals):
- Balloon Flowers
- Zinnia (cut flower)
- Sunflower (edible)
- Petunia (flowers)
- Shasta Daisy (cut flowers)
- Corn Flowers (cut flowers)
- Cucumber (edible, climbing)
- Basil (edible)
- Sweet Peas (climbing)
- Xeriscaping (see note below):
- Jade Plant (Crassula argentea) cuttings — Indoor and zones 9a–11 outdoors
- Hens and Chicks (Sempervivum) — Indoors and zones 3–11 outdoors
- Silver Mound (Artmesia) — Indoors or zones 3–7 outdoors
- Living Rock (Lithops spp. and Pleiospilos spp.) — Indoors and zones 9b–11 outdoors
*Prefers very dry conditions!
- Lavender (flowering, fragrant) — Indoor and zones 5–10 outdoors
- Pansy (flowering) — Indoor and zones 2–11 outdoors
- Sages (Salvia officinalis) — Zones 4–10 outdoors
- Purple Coneflower (flowering) — Zones 3–9 outdoors
*Draws many birds and butterflies
Note: Xeriscaping is a form of gardening that utilizes very hardy, drought-tolerant plants. One of the main goals of xeriscaping is water conservation, but this is not the only advantage. Additional benefits of xeriscaping include less maintenance, no need for pesticides or fertilizers, increased property value, and increased wildlife habitat. Most regions have a variety of native plants that may be used in this type of landscaping. Garden centers, plant nurseries, and master gardeners are excellent sources of information regarding appropriate plant selection when planning a xeriscaped garden in your area. To learn more about xeriscaping, please visit eartheasy.
- Garden Option #1: Outdoors Garden (select one or more of each plant)
- Select a garden plan appropriate for your geographic region
- Purchase plants/seeds appropriate for your geographic region
- 3–5 hand trowels/shovels
- Garden Option #2: Indoor Container Garden
- Select plants/seeds appropriate for your geographic region
- Purchase plants/seeds appropriate for your needs (light conditions, watering, etc.)
- 2–4, 1-cup-sized measuring cups or 8-oz. plastic cups for scooping dirt/sand/rock
- 1 (0.5 cubic foot or larger) bag of gravel or pea rock for the bottoms of containers
- Containers (pots or long window containers)
- Also consider recycled containers such as tomato or strawberry (produce) containers, etc.
- Soil, enough to fill your containers to approximately ½ inch below the rim
- For xeriscaping: Use a sandy mix, as described in the “Preparation” section or a “succulent and cactus” mix
- 1 pencil/pen
- 1 pair of scissors
- 1 set of the Explore: Life on Mars? Trading Cards and/or Scientist Spotlight pages
- Garden Option #3: Take–home Garden (Per child)
- Select and purchase seeds/plants
- Optional: Rooting hormone powder or gel (available at most garden centers or department stores with garden centers) *Note: This is needed only if you plan to use Jade or other plant cuttings.
- ½ cup to ¾ cup of Gravel or pea rock for the bottoms of containers
- 1 clean, empty 1L or 20 oz. plastic bottle (no lid/cap)
- 2 cups of Soil (sandy mix described in the “Preparation” section or a “succulent and cactus” mix)
- ½ cup of Water
- duct tape (in fun colors, if possible), approximately 4–6 inches per child
- 1 plant care label/card, including plant name, lighting, temperature, and watering/feeding requirements
- optional: A copy of the Extreme–O–File: Nurturing Life activity pages for this activity
- Review the activity procedures, activity pages, and background information about Mars and early life on Earth
- If possible, invite a Master Gardener to evaluate the library’s grounds for an outdoor garden and assist the children during the activity
- Print copies of the Explore: Life on Mars? scientist spotlight pages and trading cards
- Prepare the trading cards:
- Cut them out
- Optional: laminate the cards
- If possible, invite an astrobiologist, planetary scientist, or NASA Solar System Ambassador to help the children consider what life needs to survive, on Earth and perhaps on Mars, and to help them design a living garden for the library.
- Suggested online resources for connecting with scientists and female role models in your area:
- Prepare an area large enough for the children to be comfortably seated as a group
- Load the NAI Astrobiology Greenhouse Live Video Feed
Note: The live greenhouse feed can take a while to load and requires a Java plug–in. Please test it out and plan accordingly before your program.
- Optional: If you have difficulty in accessing the live NAI Greenhouse video feed, you may instead use this alternate resource, which features images and basic information about microbes and microbial mats of the variety grown and studied by scientists
- Load the NASA online video clips
- Decide which type of garden(s) best fits your facility’s/community’s needs (as well as your budget!). Take your growing zone and environmental conditions into consideration when selecting plants/seeds.
- Option #1: If planting your garden outdoors, prepare the soil and have the area ready for planting.
- If desired, involve your tween advisory council (if you have one) in the planning process. Perhaps even have them raise the funds to purchase plants for an “out–of–this–world” community garden!
- If desired, contact landscape architects, such as at the National Gardening Association, to work with your facility to create a custom garden, taking care to select plants appropriate to your location (or for xeriscaping, if that option is to be used).
- Option #2: If indoors, prepare an area for planting in containers.
- Option #1: If planting your garden outdoors, prepare the soil and have the area ready for planting.
Facilitator’s Note: A sandy soil mix may be purchased as a “succulent and cactus” mix at most garden centers. However, you may also create your own by following this easy (and less expensive) recipe: Mix together equal amounts of peat moss, coarse sand, and perlite. Perlite is used to help prevent water loss and soil compaction. All these ingredients should be readily available at a garden center or hardware store.
- Option #3: If creating take-home gardens, you should prepare the following:
- Precut the tops off the plastic bottles and tape the cut edge with a little duct tape (or masking tape) to avoid any sharp edges. You should cut the bottle a little over 1/2 of the way from the bottom.
- Check the fit of the bottle top and bottom. The bottle top should fit over the bottom section a bit (approximately 1 inch of overlap). You may need to make a small (1/2 inch) vertical slit down the side (near the top) of the bottom section to achieve the proper fit (see examples below).
Example of a plastic bottle properly prepared for the take–home garden (option #3)
- Prepare plants/seeds as needed. If using the jade plant (or plant cuttings), please review the facilitator’s note about propagating from this plant.
Facilitator’s Note: How to Take Cuttings and Propagate a Jade Plant
Propagation of selected succulents like the jade plant, Crassula argentea, is done mainly with cuttings; either leaf or stem cuttings will work. Leaf cuttings are easier to work with but take much longer to become a “jade plant.”
Materials needed: A sharp knife, liquid or powder rooting hormone (available at gardening and hardware stores), a pot, suitable soil, a parent plant (the plant from which you will take the cutting), an area where you can work, some paper towels or something to help clean up and on which to place cuttings. It is best to prepare cuttings before your program (day of).
Instructions for propagating using a Leaf Cutting:
- Place soil in the pot or container you will be using for your new jade plant and water thoroughly, letting it drain while you prepare the rest of your items.
- Cut the leaves off the parent plant and set them aside on a paper towel to dry.
(Do steps #1 and 2 before the program.)
- Give each child a leaf cutting.
- Have them dip the cut end into some rooting hormone, either liquid or powder. If using powder, you may need to moisten the stem to get the powder to stick).
- Have the children make a small hole in the dirt with a stick or their finger.
- Place the cutting into the hole, trying not to rub off too much of the rooting hormone in the process.
- Carefully press the dirt around the cutting.
- Place the planted cutting in a warm, shaded place for 3–4 weeks, and then gradually expose the plant to sunlight, moving it closer to full sun week by week. This allows the plant to develop a tolerance and increases the success of your plant. Explain to the children that it will take time, but that their leaf will develop roots and eventually grow into a jade plant that looks like the parent plant. Be sure to send plant care instructions home with the children if using with garden option #3.
Source: Jade plant care and propogation
- Optional: Review and make copies of the Extreme–O–File activity pages and/or Life on Mars? trading cards
Optional: Conduct the Ice Breaker activity: Is It Alive? to set the stage for the deeper explorations of this activity and a positive social experience.
1. Welcome the children and explain that today they will be learning about what life needs to survive and thrive and will discuss the possibility of life on Mars! By exploring what life needs and what conditions are like on Mars now and in the past, the children will work together to create a garden to both beautify the facility and share their experience with the community. Introduce the science of astrobiology – the search for life on other worlds. This activity will help them to understand why knowing what life needs is helpful to the scientists searching for it beyond Earth.
Hand out the Explore: Life on Mars? Scientist Spotlight Pages and Life on Mars? Trading cards. Give the children a few minutes to look over the scientist pages to learn more about astrobiology.
- Based on scientist features, what do you think Astrobiologists do (study)? Astrobiologists are scientists who study life on other planets.
- What is one surprising, unexpected, or interesting thing that you learned from the scientist features? Many possible answers.
- What suggestions did the featured scientists have for what it takes to be a scientist and how you can be successful? Point to specific examples in the scientist spotlight pages or trading cards: Curiosity, perseverance, asking questions, not being afraid to fail, etc.
2. Optional: Introduce and discuss the “Extreme–O–File” Activity Pages. Explain that these pages will be used during the course of the activity.
Note: You may choose to substitute the Extreme-O-File Activity Pages with the Life on Mars? Scientist Trading Cards if desired.
Optional (time permitting): Invite/Arrange for an astrobiologist to visit and speak with your group in person. Please see the “Preparation” section for suggestions.
Optional (time permitting): Play a short video of female scientists sharing what they do, such as NASA Aspire to Inspire
3. Discuss what life needs. Explain that in order for astrobiologists to detect life beyond Earth, they need to know what to look for — what life needs.Tell the children to pretend that they (the group) have been left out in the forest. They do not have anything with them.
Note: if the children have completed the icebreaker activity (Is It Alive?), then have them reflect on that experience here.
- What will you need to survive? Many possible answers.
- If someone said food — what do we get from our food? What does it do for us? Food gives us the energy and nutrients that we need to live and grow. We need energy and nutrients to live.
- Can you survive without protection? No, you will need a shelter (home).
- Can you survive without water (how long)? No, you cannot survive for more than 3 days without water! This is one of the most important/immediate needs.
- How will your needs change over time (the course of a day)? May need shelter more at night, depending on the weather, etc. Will only need to spend a part of your day on any one of your needs. The only constant need is energy – you need energy for every pursuit!
Summarize the 4 requirements for life: Nutrients (food), water, warmth (energy), and shelter (stable environment). Post them on the wall with brightly colored paper or Post–it® notes so that the children may refer to them during the activity if needed. Optional: Have the children record the 4 requirements for life in their Extreme–O–File activity pages.
Facilitator’s Note: What Does Life Need?
There are four main requirements that have been the focus of our search for life in the universe. Life as we know it needs an energy source, nutrients (something to eat or consume), protection from the elements, and liquid water. Scientists are looking for places in our solar system — and beyond — that have all the things that we know life needs.
Of the four identified necessities for life, the presence of liquid water is considered to be one of the most important and perhaps useful to scientists. Liquid water has been a focus in the search for life beyond Earth because, to date, we have only found living organisms where liquid water exists. Pure water is a liquid over a fairly wide range of temperatures — between 0°C (32°F) and 100°C (212°F). Under special circumstances, however, water can remain a liquid beyond this range. For example, at high pressures (like at the bottom of the ocean or deep in Earth’s crust), water can remain a liquid to higher temperatures. Similarly, saline water (water containing salt like our ocean water) has a lower freezing temperature, allowing it to remain a liquid at temperatures that are colder than the normal freezing point. Temperatures much above or below this normal range for liquid water, though, negatively affect the cellular structures of living organisms — potentially destroying them. The presence of water on a planetary body is one requirement for life to exist there (past or present), thus scientists are interested in identifying locations in the universe that possess water — especially liquid water — to better narrow their search for life beyond Earth!
For more information about the requirements of life, please refer to the Facilitator Background Information.
4. What is it like on Mars? Discuss the challenges that living things on Mars would face and describe that the children will use their understanding of life’s needs to create a garden.
Play the following video clips and then discuss, or as an alternate option, you may ask the children to browse through some non–fiction science books about Mars from your collection. Please see the module resource list for book suggestions.
Mars in a Minute: Is Mars Really Red?
Mars in a Minute: Is Mars Red Hot?
- Is it closer or farther from the Sun than Earth? Farther
- Is it hotter or colder than Earth? Colder
- What would it be like to live on Mars? Are there mountains? Rivers? Forests? What is the weather like? There are mountains but no forests or rivers. There are features that look like rivers on Mars, that may have been active long ago, but they do not contain water today. It is very cold, dry, windy (at times), and dusty on Mars.
- How is Mars different than Earth? Smaller, drier, colder, less atmosphere (less protection from radiation), longer year/seasons.
- Do you think Mars can — or could in the past — support life? We haven’t yet discovered life (past or present) on Mars. However, it is possible that Mars had life in the past — and perhaps still does. Thinking about what life needs, we know:
- Water? Mars has water ice at the surface and possible liquid water below the surface.
- Nutrients — Yes.
- Energy source — Yes (Sun).
- Shelter/protection — Yes (more atmosphere in past; below ground now?).
- What type of life might (have) exist(ed) on Mars? Plants? Animals? Bacteria?
- Optional: Have the children complete the “What is it like on Mars?” question on their Extreme-O-File activity page.
Note: If you have not previously completed the Mars by the Book activity, you may want to incorporate the non–fiction books and research from that activity here (time permitting). This will allow the children to discover what it is like on Mars for themselves instead of simply being told.
5. Discuss the similarities and differences of your garden compared to the life forms that could be on Mars. Hand out copies of the NAI Extremophile Trading Cards and have the children look at the images of Mars-like locations on Earth and the organisms that live there. Also have them look at the extremophile features in a set of Life on Mars? Trading Cards.
- Are there plants like the ones that we will plant in our garden on Mars? No! Show images of the Mars landscape here, if desired.
- What type of life might exist — or have existed — on Mars? Dogs? Flowers? Bacteria? Mold? Microbes! If life exists or ever existed on Mars, it was likely in the form of microbes! Microbes (microscopic organisms) are very tiny — you can’t see them with the naked eye because most of them are single-celled — you would need a microscope to see them! Some examples of microbes include bacteria, fungus (mold and yeast), and protists (microscopic plants), like green algae.
Note: If you have previously conducted the Searching for Life activity, remind the children of their experiment involving the three soil samples. Recall that the soil sample containing life had yeast (a type of fungus) and sugar in it. Remind them that we use yeast in our food — such as breads and pastries — yum!
Optional (time permitting): Give the children a few minutes to browse through nonfiction books about extremophiles and life beyond Earth from your local library.
Optional: Have the children complete the final question on their Extreme-O-File activity page.
It is important for the children to understand the connections between their garden and the types of life that may have existed on Mars in the past. In particular, they are planting a garden with multicellular plants, but any possible life forms on Mars are likely much less evolved or complex (i.e., microbes) and not visible with the naked eye. Use the questions above to help them to picture the conditions on Mars, focusing their attention on what life needs. Use the NAI Extremophile Trading Cards to help them to understand the differences between the type of life that would be possible on Mars and the Earth analog. Explain to them that an analog is a place/organism on Earth that has some important similarities to the places/possible life forms on another planet, such as Mars. Analogs help scientists to understand how life may have developed on other planets and places, such as Mars.
Might There be Life on Mars?
Conditions on early Mars may have been much more like conditions on early Earth (geologically active, warmer, wetter, etc.). By understanding early life here on Earth (analogs), astrobiologists are hoping to discover how best to search for it elsewhere, such as on Mars. Scientists are using this understanding to narrow our search for life beyond Earth to those places that possess the requirements of life (e.g., liquid water, moderate temperatures, etc.).
All life as we know it requires liquid water, hence the interest in finding evidence of past liquid water on Mars, and understanding the history of this water. There is strong scientific evidence that liquid water once occurred on the surface of Mars, so it is possible that life could have become established. The first conclusive fossil evidence for life on Earth, in the form of fossil bacteria, occurs about 3.5 billion years ago — the time that the martian environment was changing from warmer and wetter to colder and drier. Microbial life on Earth probably existed before this time period, possibly becoming established after the period of intense asteroid bombardment was over, but there is no record of it. In short, it may have taken life up to a billion years to become established on Earth, although it may have happened more quickly, and so scientists consider this to be a reasonable timeline for Mars as well.
Given this start, and using Earth as a model, conditions on much of Mars would have been suitable for life for about 500 million years before the climate deteriorated. However, the features recording flooding events suggest that there were occasional warmer and wetter periods, and there may have been refuges for life, such as moist areas near warm volcanic regions. Given the harsh conditions, and lack of evidence, it is unlikely that life evolved into complex multicellular forms, like it did on Earth between 1 billion years and 500 million years ago.
6. Optional (time permitting): Research how to grow a garden. Explain that they will use what they learn to help build a garden to beautify the library. Please allow 15–20 minutes to complete this step, keeping this in mind when planning your children’s program. Note: This garden may use xeriscaping, a type of gardening that uses hardy, drought-tolerant plants, to help represent the harsh climate on Mars if desired.
- Divide the children into groups of 3–4 and give each group 1–2 books about gardening. Ask each group to spend 5–10 minutes looking through the books together and discuss useful tips for gardening. What will they need to do?
- Discuss the groups’ findings. Let each group share something that they learned or found in their books. These questions may be useful in shaping your discussion:
- Who has ever helped in the garden (at home)? Ask for a show of hands.
- What do we need to grow a garden? A place/soil, sunlight, water, etc.
- One-time needs: Soil, seeds/plants, pot/garden area, etc.
- Ongoing needs (i.e., life’s needs): Sunlight, nutrients, water, etc.
- Summarize the group’s findings.
7. Create a garden. Have the children work as a group to put their knowledge of life to the test by sustaining life in a garden! Make sure to follow the planting instructions that came with your plants or seeds. Conduct one or more of these options:
Garden Option #1: Plant an outdoor garden on the grounds of the facility. Discuss how your garden is related to life that would be possible on Mars. Work as a group, taking turns, to plant the garden. Make sure to water the new plants/seeds carefully after planting (with close adult supervision).
Garden Option #2: Plant an indoor garden in a container(s). Discuss how your garden is related to life that would be possible on Mars. Work as a group, taking turns, to plant the garden. Make sure to water your new container garden after planting, using either a pitcher or watering can.
Garden Option #3: Invite participants to construct a take-home garden in a bottle. Explain that their bottle will require all of the ingredients for life that were discussed, and they will be responsible for taking care of them at home. Give them a note card or label with plant care instructions. Optional: Have the children record the directions for caring for their plant at home in their journal and show them the area in their journal for recording observations at home. Option #3 is recommended to be conducted in support (conclusion) of either option #1 or option #2, but may be used on its own if desired.
- Constructing a Take-Home Garden:
- Put ½–¾ cup (you may use an 8-oz. plastic cup) of rock into the bottom of the bottle.
- Add 2 cups of your soil mix into the bottle. The soil level should be located about 1/2–1 inch below the top of the bottom section of the bottle.
- Plant your plants or seeds according to package directions. For jade plant (or other) cuttings please see the jade plant facilitator’s note for instructions.
- Add about ½ cup of water to your bottle, or until there is approximately 1 inch of water in the bottom of the bottle (in the rocks).
- Replace the top of the plastic bottle so that it fits around the outside of the bottom.
- Secure the top of the bottle (without cap) in place with a piece of duct tape.
- Have the children take their “garden” in a bottle home and encourage them to keep a daily journal of their plant.
- Optional: Hand out preprinted plant care labels to each child and have them affix it to the side of their bottle, in order to help them remember how to care for their plant at home.
8. Discuss how the garden has the same needs as life that might exist — or have existed — on Mars in the past. They will be responsible for providing for the needs of their plants to take home and/or the garden at the library!
9. Discuss briefly how astrobiologists search on Mars for the same support for life that they created in their garden(s): water, nutrients, shelter (or at least a stable environment), and energy.
Summarize what life needs to survive (water, sunlight, warmth, nutrients) may have been present on Mars in the past. Today, astrobiologists are using their understanding of life on Earth to better understand life beyond our planet in places such as Mars, where it appears that the right ingredients for life may have been present (or may still be). While life was beginning on Earth, it may have also been present on Mars! Your garden is a reminder of life’s needs. However, the type of life in your garden is quite different — much more evolved and complex than what life forms on Mars would be. Any life on Mars would likely be simple, single-celled microbes, similar to the extremophiles that you discussed during the activity.
Create a poster as a group about your garden to put on display in the facility for your community. Using what you have learned and the Extreme-O-File astrobiology resources, have the children work as a group to create a poster describing the project to put on display. You may cut out and use parts of the activity pages and resources (make sure to have extra copies available for this purpose), as well as creating text and artwork to include on the poster. They should be sure to include the following:
- The four requirements for life? Water, energy, protection, nutrients.
- What is it like on Mars? Compare temperature, water, etc., on Mars versus Earth.
- Why are scientists searching for life on Mars (past or present)? Mars has water — evidence of liquid water at the surface in the past — and may be able to support some forms of life (such as extremophiles).