Inquiry Skills UsedThis is a research activity with students using observation and data collection.

Safety Considerations Even though this is an incredibly safe activity, it provides a great opportunity to model safety practices, such as using our senses safely when observing and working carefully. Make the celery stalks short enough so that the plastic cups will not tip over when the celery stalk is placed inside the cup. If using warm water, caution the students about the water temperature. If using a heat lamp, caution the students not to touch the heat source. Teachers are reminded when unplugging an appliance, unplug by pulling on the plug, not the cord.

BackgroundChildren can identify that water exists in 3 states within our natural environment. Plants can use this water, in either liquid or vapour form, to survive.

What You Need Ice cube trays Clear plastic cups Freezer and refrigerator Food colouring Water

Celery stalks Paraffin wax/vegetable oil Re-sealable plastic bags Recording sheets A heat lamp may be necessary if there is

no source of sunlight

What to Do1. Begin with a discussion asking where plants get the water they need to survive. Tell the students

that water comes in three states, solid, liquid, and gaseous. Plants are surrounded by water in the form of vapour in the air. Can plants use that water vapour in order to survive? Can plants get the water they need in winter from the frozen water in the ground? When roots bring water into the plant, where does it go and what is its state?

2. Mix food colouring into water to make coloured water. Make coloured ice cubes by putting some of the water into ice cube trays and allowing it to freeze.

3. In this activity, the students will use a different plastic cup for different states of water.

Cup 1—Fill the cup about one third full of coloured water and put in a celery stalk. Cup 2—Place coloured ice cubes into the bottom of the cup. Put the end of the celery stalk on top of the

ice. Put the cup in the freezer.

This activity is suggested for use with the Ontario Curriculum.

Grade 2: Earth and Space Systems

Contributed by: Ellen Webb

Changes to air and water affect living things and the environment.

Air and water are a major part of the environment.

Cup 3—Fill the cup about one third full of coloured water and put in a celery stalk. Put the cup in a sealed plastic bag. Flatten the top of the plastic bag in order for the condensation to form.

Cup 4 - Put a celery stalk into a cup. Put the cup into a sealed plastic bag. Do not put any water into the cup. Flatten the top of the plastic bag or order for any condensation to form.

Cup 5—Fill the cup about one third full of warm coloured water. Put in a celery stalk. Cup 6—Place a celery stalk in an empty cup.Cup 7—Fill the cup about one third full of cold coloured water and put in a celery stalk. Put the cup in the

refrigerator. This activity works best if the class is divided into 7 groups and each group is responsible for making and recording observations for each cup, and conducting any subsequent activities. Each group records their observations every half day for one week. They will present and compare each of their observations at the end of the week.

SummaryThe students should observe the colour moving up the stalk as the coloured water enters the celery. Coloured water will not move up the stalk from the frozen water. A little condensation will form on the bag in Cup 4, where no water is added. This is water transpiring from the celery stalk. The stalk will become flaccid as water leaves the celery. A greater volume of water will condense on the bag from Cup 3 and colour will move up the stalk. The colour will move up the stalk faster in Cup 5 with warm water, compared to Cup 1 with cooler water.

Where to Go from Here?Many vegetables are coated with wax (e.g., rutabaga) or vegetable oil (e.g., peppers, eggplant, tomatoes). Coat a celery stalk completely with vegetable oil or melted paraffin wax and leave it in a cup with no water added. Note the difference between this celery stalk and the celery stalk in Cup 6. Water should not be able to transpire through the stalk as the oil or wax forms a barrier, keeping the water in the stalk.

Try placing a potted plant into a large clear plastic bag and observe how many weeks or months the plant will survive without adding water.

STSE LinksDiscuss how grocers coat vegetables in order to extend their ‘shelf life’ so that they remain fresher longer for the consumer. Discuss the importance of washing fruits and vegetables to remove preservatives and pesticides from the skin or surface. Discuss how ‘eating local’ reduces our carbon footprint as less energy is needed to keep foods fresh before they reach the consumer.

Cross Curricular ConnectionsLanguage : Media Literacy

Take pictures of the celery stalks showing how they become flaccid over time or the colour rising in the stalks.

Social Studies Take students to a local grocery store. Note where the food originated on the fruit or vegetable

description (Product of….). Ask the grocer to show students methods they have for keeping vegetables fresh longer in the store (sprinklers, damp covers for overnight, vegetable oil, wax, cool temperatures, bags with air holes, cardboard containers, loose packaging, paper bags rather than plastic, etc.).

Mathematics

Measure the height of the colouring in the celery stalks. Scrape the condensation from the plastic bags and record the volume of water transpired by the

celery. Use data management skills to plot the height of colour on graphs.

Visual Arts Draw what students observe and label the diagram.

Credit Where Credit is Due

This activity was adapted from Activity 77—A Wilting Contest in Botany for All Ages by Jorie Hunken.