This experiment is in the ‘Try it Yourself’ section of Marlow Brown: Scientist in the Making. I’ve included it again here in case you’ve lent your copy to a friend (well done you!), returned it to the library (always best if you want to avoid late fines), or your dog has stolen yours and buried it in the far back corner of your garden. (I’d be having serious words with your dog if this is the case. Let me know if you’d like Rockstar to come over to sort things out. He’s good at finding buried stuff.)

Hypothesis

Decide what you want to test and write down your hypothesis. You might use the same hypothesis as Marlow (that putting dye in the water of a vase of flowers changes the colour of the flowers), or you could test one of these:

1. Adding red, blue and green food dye to the water of a white flower will turn the petals grey.

2. Some colours are absorbed by white flowers better than other colours.

3. How much a flower changes colour when you add food dye to the water depends on what type of flowers you use.

Equipment

This will vary depending on your hypothesis, but basically you will need:

1. White flowers (You could try carnations, daisies, roses or any other white flowers.)

2. One small glass jar for each flower stem

3. Water

4. Food dyes (You might want to try a different colour in each jar; or if you are testing out different flower types, you might want to use one colour only so you can compare your results more easily.)

5. Sharp scissors (Ask an adult for permission to use them, for safety’s sake!)

Method

1. Half fill each glass jar with fresh water.

2. Add the same amount of food dye to each jar so that the water is quite a deep colour. (It may be best to have a grown-up watch you do this part.)

3. Trim each flower stem with scissors to exactly the same length. (This is so that the water has the same distance to travel up every stem.) Make sure there are no leaves left on the stem. (It is best to cut the stem on an angle rather than straight across as it will absorb the water better.)

4. Place one flower stem in each jar.

5. Watch and wait! (But remember, it could take a few hours before you see any change. Or even a day or two. If you make a note of the time you start, you may be able to work out how fast your flowers drink. I wonder if some types of flowers drink faster than others. Now there’s another idea to test!)

Results and Conclusion

When you’ve done the experiment and found out if your hypothesis was correct or not, feel free to share your results (what happened) and conclusion (what you found out) by telling us about it in the comment box below.

Contributing Scientist: Marlow Brown