Part 10 – Scientific Discovery

(The World Around Us)

Complete any TWO of the following:

Plant a seed in cotton wool. Keep it moist and watch what happens You will need (for each cub):
  • a plastic disposable cup or bowl
  • cotton wool
  • about 10 wheat seeds
What to do

Write the cubs’ name on the edge of the bowl
Cover the bottom of the bowl/cup with cotton wool.

Place wheat seeds in the bowl. It helps if you place the seeds with their grooved side upwards.

Wet the cotton wool and take the bowl home. At home put in a light place. Keep the seeds moist — you could cover the bowl with clear plastic wrap to prevent the seeds from drying out.

Within four or five days, the seeds should begin to grow.

Observe the seeds growing for a few more days.
Mustard and Cress seeds are even better, as the cubs can then trim the sprouts and have them on a sandwich when they have grown enough.


Identify five different rocks and tell where you found them One site that will make it easier for cubs to identify their rocks is


Explain the composition of air
  • 99.998% of our air consists of
  • Nitrogen (78.084%)
  • Oxygen (20.947%)
  • Argon (0.934%)
  • Carbon Dioxide (0.033%)
The Remaining .002% is made up of
Neon, Helium, Krypton, Sulfur dioxide, Methane, Hydrogen, Nitrous Oxide, Xenon, Ozone, Nitrogen dioxide & Iodine, plus a tiny trace of Carbon monoxide & Ammonia


Perform an Experiment that shows how oxygen can be used up WHERE DID THE AIR GO?

You will need –

  • A Small candle (a tea candle is often the best for this)
  • A drink glass
  • Small plate or deep saucer
  • A milk bottle lid
  • 3 small nails, screws or similar
  • Matches/lighter
Instructions –
  1. Place about 1cm of water into the plate
  2. Place the candle on the bottle-top, in the middle (candle should be clear of the water)
  3. Place the 3 nails/screws equally around the candle in the water. The glass will go upside down supported by the screws. (this allows the water to flow in/out and avoids any risk of a vacuum forming inside the glass).
  4. Light the candle.
  5. Place the glass over the candle, with the open end sealed by being under the water.
  6. Observe the results!
Explanation: Air is made up of many different gasses, however 99% is only 2 gasses – being Nitrogen (78%) and Oxygen (21%).

How do we prove there is actually oxygen in the air? – We know that one of the things that fire needs to sustain itself is oxygen. If we remove the oxygen, the fire will go out. In this experiment we isolate the candle from the atmosphere using the glass. If there is oxygen in the air the candle will keep burning.
However, if that oxygen gets used up, the flame should go out. So we should observe the flame being extinguished. This is due to the oxygen in the glass being consumed by the flame, while carbon dioxide is being produced at the same rate causing no real change in the amount of gas. What is happening though is the candle is warming the air in the glass while it is alight, increasing the volume (causing bubbles out of the bottom of the glass). When the candle goes out the air in the glass cools causing a decrease in volume and hence causing the water to be drawn into the glass.
You will notice by doing the experiment that the water only creeps up the glass when the candle dies down and keeps creeping up after it has gone out!

Measure your foot and hand.
Using this knowledge, estimate
  • the width of your hall,
  • the height of a Cub Scout in your Pack
You will Need:
  • a ruler
  • your scout hall
  • A cub scout
Instructions –
  1. Using the ruler, measure the length of your hand in Centimetres
  2. Using your hand, count how many “hands” tall one of the other cubs is.
  3. Using the known length of your hand, work out how high the cub is.
  4. Using the ruler again, measure the length of your foot in Centimetres
  5. Using your foot, count how many “feet” wide the hall is.
  6. Using the known length of your foot, work out how wide the hall is.
Explanation – Often it is not possible to accurately measure distances. For instance, the rulers we use are usually only 30cm long, but we want to measure something much larger, and that is why we estimate.
This task demonstrated one method of estimating. It uses an object of known length (hand or foot) to estimate something much larger than that object.

A common use of this method is during a hike. The hiker counts how many paces they have taken to estimate how far they have traveled. Another is the odometer in a car, which in simple terms, works by counting how many times the car wheels have turned to estimate the distance the car has travelled.


© 2008 Ian Moggs - rights are given for copying and printing for personal use or use in cub-scout or similar groups.