Handkerchief (fine weave) - PDF document

1 Handkerchief (fine weave) 2 Water (add food colour if desired) 1 Use a rigid plastic cup if you are concerned about the safety of students repeating the demonstration with glass The glass does not need to be full to the brim 3 Push the centre of the handkerchief deep into the water so that it becomes thoroughly wet 4 Stretch the top of the handkerchief taut across the rim by pulling it down the outside of the glass – you should feel some resistance and there should be no creases on the rim Teacher Demo 14 – Magic Hanky | Page 1 2005 | ABC Science Online Nutrition and sugar in softdrinks Students can be encouraged to make better choices by discussing the difference between hunger and thirst. The following considerations may help your students make better choices in the future: Our amazing bodies use various sensations to let us know all kinds of important things such as when we are becoming too cold (which can lead to hypothermia and death), or too hot or when we are injured, so that we avoid further injury When our body requires energy, we experience a hunger sensation (ie rumbling tummy) When our body requires water, we experience a thirst sensation (ie dry mouth) If you drink softdrink, fruit juice, milk or cordial when you feel thirsty, you are also giving your body some energy which it wasn’t necessarily asking for (ie thirst is not the same as hunger – you don’t eat because you’re thirsty and vice versa) If you are going to drink softdrink, make sure you don’t drink too much and remember that a 250ml glass of softdrink contains about 7 teaspoons of sugar, a whole can contains about 10, and a 600 ml bottle contains up to 18! Make sure you always do at least 30 minutes of physical activity every day, and more if you can, and consider how much energy you’re putting into your body Take more notice of what you eat and how much energy your body is receiving through food and drinks by reading nutrition labels and don’t forget that even healthy choices such as fruit juice and milk contain energy! Consider the table below and calculate the fraction of the recommended daily energy intake contained in one 600 ml bottle of softdrink (depending on age and gender, it ranges from almost 10% to nearly 20%!) Recommended Energy Intakes for Males and Females Age Kilojoules per day Males Females 6 – 7 7900 7100 7 – 8 8300 7400 8 – 9 8700 7700 10 – 11 9000 7900 11 – 12 8100 – 9100 7300 - 8200 12 – 13 8300 – 9800 7700 – 8700 13 – 14 9200 – 10,300 8100 – 9100 14 – 15 9800 – 11,000 8400 – 9500 15 – 16 10,500 – 11,800 8600 – 9800 16 – 17 11,100 – 12,500 8300 – 9900 18 – 30* 11,700 – 13,200 8800 – 10,000 Recommended Dietary Intakes for Use in Australia * For Height 170cm / Weight 65.0kg More information: Australian National Health and Medical Research Foundation s for Use in Australia http://www.nhmrc.gov.au/publications/diet/n6p4.htm#app2 Australian Bureau of Statistics National Nutrition Survey: Nutrient Intakes and Physical Measurements Australia http://www.abs.gov.au/Ausstats/abs@.nsf/0/95e87fe64b144fa3ca2568a9001393c0?OpenD Safety notes There are no specific safety notes for this demonstration, however you should always consider the particular needs of your studen Teacher Demo 14 – Magic Hanky | Page 3 2005 | ABC Science Online