Up and Down and Water Smart Activity

Up and Down

The Earth's huge mass exerts a gravitational force which pulls us down. This force is the reason things fall towards the Earth. Up is what we consider to be the opposite of down. All around us we have signs that help us figure out which is up and which is down. The sky, the ceiling, and the cookie jar on top of the fridge are all perceived by human eyes as being "up". On the other hand, the grass, the floor, and toys beneath the bed are all things we think of as "down". Aboard the Space Shuttle or the International Space Station (ISS), astronauts live in microgravity where there are no gravitional or visual cues to help them determine which is up and which is down. As a result, when an astronaut first reaches space, a period of adjustment (about two days) is required to have their senses adapt to the weightless environement.

Here is an activity that will challenge your senses into figuring out which way is up and which down.


For each team or group (four to five people)

You will need:

  • A box large enough for someone to sit in, opened at both ends and decorated on the inside
  • A large piece of cardboard to act as a box lid


Decorate the inside of the box and the lid with wall paper, coloured shapes or magazine pictures make sure the images are all facing the same direction

  1. Choose one team member to sit inside the box on the floor. Cover the top with the lid. Ask what he/she sees.
  2. Remove and invert the box over the person, while he/she is sitting with his/her eyes closed. Replace the lid. Ask again what he/she sees.
  3. Repeat with another team member and compare their reactions
  4. Together decide what explanation there might be for any differences.
  5. Share and compare your team's findings with another team.

Did you reach the same conclusions?


  1. Help students see the importance of our eyes in helping orient us to "Up" and "Down", by asking what sense(s) they used to decide if the box was right side up or upside down.
  2. Point out that even though some students may have felt somewhat disoriented they still had the floor to help orient themselves. Relate this to the experience of the astronauts in microgravity who have no up or down cues at all.

Water Smart Activity

Since water is a rare commodity in space, astronauts on the International Space Station (ISS) will be recycling their water. This includes respiration, perspiration, shower and shaving water, and even urine. This wastewater will be purified and then recycled for drinking and other uses.

Biological treatments are used to purify water on Earth. The micro-organisms used in this process destroy contaminants in the water. The International Space Station (ISS) will use physical and chemical processes to remove contaminants, along with filtration and temperature sterilisation to ensure the water is safe to drink.

Try this water filtration activity with your classmates. Note: This experiment only demonstrates a type of water filtration. The experiment will not purify water for drinking purposes.


You will need:

  • Clear plastic soda bottle (2-litre)
  • Gravel (aquarium)
  • Sand
  • Aquarium charcoal (activated)
  • Cheesecloth (a nylon stocking can be used instead)
  • Muddy water
  • Rubber bands


  1. Cut the bottom off the soda bottle. Cover the mouth with several layers of cheesecloth and secure the cloth with a rubber band. Suspend the bottle upside down with its mouth over a glass to catch the filtered water.
  2. Fill the bottle with charcoal to a depth of 5–8 centimetre (cm). 
  3. Place 8–10 cm of sand on top of the charcoal. Place 5–8 centimetre cm of gravel on top of the sand.
  4. Stir the muddy water and pour it into the filter. Watch closely as the water seeps down through the three filtering layers of gravel, sand, and charcoal.


  • What happened to the water while it passed through the different layers of the filter?
  • Compare the muddy water to the filtered water. Is there a difference?
  • Would it make a difference if one of the layers had been left out?