Discuss Talk to your
Discuss Talk to your buddy about how you will find out which is the best material for a hankie. Getting started EEZE Get some different materials. Put a piece of material in a tray. Drip coloured water onto the material. Does it soak up the water? How will you decide which is best at soaking up the drips of water? How will you make sure that everything is fair? Test your ideas Can you think of other ways to find out? Share your ideas Put the best hankie on the winners’ podium. Extra things to do Can you do any other tests to decide which hankie is the best? Find out why it might be better to have a hankie that you can throw away after you have used it. British Science Association Registered Charity No. 212479 and SC039236 28
TESTING TIMERS TESTING TIMERS Testing Timers Organiser’s Card About the activity This activity is designed to get children thinking about how sand timers work. Cosmic and Gem are practising for sports day. They need a timer to work out how many balls they can get into the bucket in one minute, but they are not allowed to throw balls in the kitchen near the clock. They want to make a timer to take into the garden. Uncle Astro thinks that they can use sand to make a timer. Through this activity you will support your group to: • Compare real sand timers and observe what variables effect the time they measure • Experiment with different hole size and quantities of sand in their own sand timer • Test their sand timer and reflect on how it could be improved Kit list • Sand timers • Dry paper cups (washed used ones will be fine) • Dry sand • Covering for tables • Sharp pointed pencil to make holes • Stopwatch or clock with second hand • Water, sugar, salt etc (optional) What to do 1. Introduce the activity by reading the story on the activity card together. Get the children to talk to a buddy about the questions and the opinions of Cosmic, Gem and Uncle Astro. 2. Discuss how to make sure they carry out the task safely. 3. Let the children look at real sand timers first. Then encourage them to explore different cups and sizes of hole before they try to make their one-minute timer. 4. Talk together about what they have found out. Can they explain why they have different answers to how much sand you need? What would they change to improve their timer? 5. Children can create labelled pictures or photographs of their timer. Encourage them to add as much detail as possible including design features and the amount of sand. 6. There are follow up activities for children who have finished or who want to do more finding out at home and earn a bonus sticker. They can try out each other’s timers by playing the ‘ball and bucket’ game. 29
