Station 1

Giant Sequoias The giant sequoia tree is one of the largest trees on earth. It starts as a small seedling and grows into an enormous tree. Five children can stretch their arms across the width of the trunk of one of the large sequoia trees! Where did most of the matter that makes up the wood and leaves of this huge tree originally come from? Write down the best answers: sunlight water soil carbon dioxide oxygen minerals chlorophyll

Station 2

Plants in the dark and Plants in the light

Four friends wondered how light affected the growth of plants. They decided to test their

ideas using young bean plants. One set of plants was put in a dark closet for eight days. The

other set of plants was put on a shelf near a sunny window for eight days. The friends then

measured the height of the plants after eight days.

This is what they predicted:

Carl: “I think the plants in the dark closet will be the tallest.”

Monique: “I think the plants by the sunny window will be the tallest.”

Jasmine: “I think the plants will be about the same height.”

Drew: “I think the plants in the closet will stop growing and die.”

Which friend do you agree with?

Station 3

Is it food for plants?

Organisms, including plants, need food to survive.

Which of these things do you think plants use as food?

sunlight

soil

plant food from a garden

store

water

sugar

leaves

carbon dioxide

oxygen

minerals

chlorophyll

fertilizer

vitamins

Station 4

Is it a plant?

Each of the things listed below can be found living and growing in its environment.

Which of these things are NOT plants?

fern

grass

moss

vine

grasshopper

tomato

mold

flower

tree

onion

weed

bush

cactus

bacteria

mushroom

cabbage

dandelion

carrot

Station 5 Seedlings In A Jar

Imagine you have a sealed jar containing five bean seeds, air, and a moist paper towel. Nothing can get in or out of the jar. The total mass of the jar and its contents is 500 grams. Imagine the same jar with its contents 12 days later. During that time the jar remained sealed. Nothing could get in or out of the jar. The seeds have germinated to form 6-centimeter seedlings. The total mass of the jar and its contents after the 12 days is recorded. Which statement is the best comparison of the total mass of the jar and its contents before and after the seeds sprouted to form seedlings? A The total mass of the original jar with seeds will be more than the total mass of the jar with the seedlings. B The total mass of the original jar with seeds will be less than the total mass of the jar with the seedlings. C There will be no change in the total mass of the jar with seedlings after 12 days.

Station 6 Respiration

Which organisms on this list use the process of respiration?

human

grass

duck

frog eggs

mushroom

tomato plant

fish

chick inside an egg

human body cell

germinating seed

horse

apple tree

worm

single-celled pond organism

honeybee

bacteria

butterfly larvae inside a

chrysalis

Station 7 Chlorophyll

Chlorophyll is a substance found in the cells of plants. Which of these are functions of chlorophyll? -Provides protection for the leaf -controls the odors that come from a plant -serves as a storage product in a plant -is a source of food for a plant

-absorbs light energy -absorbs carbon dioxide -strengthens plant cells -breaks down sugars and starches -gives most plants their green color

-is a vital liquid in plants that acts similar to blood in animals -attracts bees and butterflies to the plant for pollination -manufactures food for the plant

Station 8 Apple Tree

Six friends were picking apples. They each had different ideas about where the apple tree makes the food it needs to live and grow. This is what they said: Molly: “I think the food is made in the tree’s roots.” Joan: “I think the food is made in the leaves of the tree.” Bonnie: “I think the food is made in the apples the tree produces.” Bev: “I think the food is made in the tiny tubes in the trunk and the branches.” Susie: “I think the food is made in the apple blossoms.” Jared: “I disagree with all of you. I don’t think apple trees make their own food.” Which friend do you agree with the most?

Station 9 Light and Dark

Five friends were talking about when plants carry out the processes of photosynthesis and respiration. This is what they said: Janet: “Photosynthesis and respiration occur both when it is light and when it is dark.” Calvin: “Photosynthesis occurs when it is light; respiration occurs when it is dark.” Mika: “Photosynthesis occurs when it is light; respiration occurs both when it is light and when it is dark.” Turner: “Photosynthesis occurs both when it is light and when it is dark; respiration happens at night.” Sophie: “Photosynthesis occurs in the light; plants don’t carry out the process of respiration.” Whom do you agree with the most?

Station 10 Food For Corn

Eight farmers were talking about their cornfields. They each had different ideas about the food their corn needed to grow. This is what they said: Mrs. Farrin: “My corn plants use sunlight as their food.” Mrs. Tobias: “My corn plants use food they get from the soil.” Mr. Cullenberg: “My corn plants use sugar as their food.” Mr. King: “My corn plants use food from the fertilizer I give them.” Mrs. Joslyn: “My corn plants use carbon dioxide and water as their food.” Mr. Cody: “My corn plants use food from the chlorophyll in their leaves.” Mr. Trask: “My corn plants use food from the ears of corn they produce.” Mrs. Ahlholm: “My corn plants don’t use food; instead, they make food for animals to eat.” Which farmer do you agree with the most?

Answer Key Station 1: The best response is D, carbon dioxide. Plants take in carbon dioxide (a gas) through their leaves and water from the soil and use the energy from sunlight to rearrange the atoms into new substances—sugar and oxygen. Most of the matter, including the leaves and wood, that makes up the structure of the tree can be traced back to the carbon dioxide that was transformed into sugar through photosynthesis and used for building material. The mass contributed by the carbon dioxide is much greater than the mass contributed by the water.

Station 2: There is no one correct answer for this probe because plant growth depends on several conditions.

Station 3: The best response is sugar. Sugars, such as glucose, are simple carbohydrates made and used by plants as food. Plants differ from animals in that they are able to use the energy from sunlight to transform inorganic carbon dioxide and water, which they take in from their environment, into food. This process is called photosynthesis. Part of the confusion among children and adults is due to how we define the word food and use the words food and nutrients interchangeably. Nutrients are substances that organisms require to carry out their life processes; they can be organic or inorganic. Not all nutrients provide energy. Examples of inorganic nutrients that do not provide energy are vitamins, minerals, and water. Examples of organic nutrients that provide energy are carbohydrates (including simple sugars), lipids (fats), and proteins. Food is a nutrient that contains energy, and it may contain inorganic nutrients as well. Food provides energy and the building blocks for growth and tissue repair; it can be used immediately or stored for later use. For example, many plants store food in the form of starch. All foods can be considered nutrients, but not all nutrients are considered food. To be considered food in a biological sense, the substance must contain energy that can be released during cellular respiration.

Station 4: The items on the list biologically considered to be plants are fern, grass, moss, vine, tomato, flower, tree, onion, weed, bush, cactus, cabbage, dandelion, and carrot. Plants are multicellular organisms that are generally able to make their own food through photosynthesis. Many plant cells contain pigments capable of absorbing light. Plants have a structure called a cell wall, which is made mostly of cellulose. Plants can vary in size, from tall trees to short mosses. Some of the items on this list are “plantlike” but are not plants. For example, mushrooms and mold are classified as fungi. Their cell walls are generally made of chitin instead of cellulose, and they do not make their own food or contain light-absorbing pigments within their cells. The grasshopper is a green animal; some students think that anything green is a plant. Bacteria are prokaryotic organisms, meaning they lack membrane bound organelles like those found in plants, even though bacteria have a cell wall and some bacteria are capable of photosynthesis.

Station 5: The best response is C. The probe explicitly states that nothing can get in or out of the jar—it is a closed system. An interaction occurs as food contained in the seed is transformed chemically into new matter that makes up the plant structures of the seedling. An interaction also occurs between water, oxygen, and carbon dioxide in a cycle of photosynthesis and respiration that results in the building of additional plant material. All of this occurs inside a closed system. The atoms that made up the original matter in the seed, air, and water are rearranged and found in new plant structures, but no mass is added or lost in the total system.

Station 6: Everything on the list uses the process of respiration. Respiration is an essential life process carried out by all living organisms—from single-celled to multicelled—to provide the energy that organisms need to function.

Station 7: There are two best responses—E and I. Chlorophyll is a pigment found in the chloroplast of plant cells (as well as many single-celled organisms). The primary function of chlorophyll is to absorb light energy (E). Chloroplasts convert light energy to chemical energy using chlorophyll. Chlorophyll also makes most plants appear green (I), although this is a passive function as the chlorophyll molecule simply reflects green light rather than absorbs it and makes plants appear green to our eyes.

Station 8: The best response is Joan’s: “I think the food is made in the leaves of the tree.” Trees are plants and,

therefore, they make their own food.

Station 9: The best answer is Mika’s: “Photosynthesis occurs when it is light; respiration occurs both when it is light and when it is dark.” The word photosynthesis means to “make with light.”

Station 10: The best response is Mr. Cullenberg’s: “My corn plants use sugar as their food.” Plants take in carbon dioxide through their leaves and water through their roots and use energy from sunlight to break apart and reassemble these molecules into a carbohydrate in the form of a simple sugar. This simple sugar (glucose) is often converted to a more complex sugar such as sucrose, starch, or cellulose. Plants can use the food (sugars) they make immediately or store it for later use. Sunlight is the source of energy for the food-making process of photosynthesis, but, by itself, it is not food.