TESTING TIMERS TESTING

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.

Things to think about Some children may not have seen sand timers, so they need to play with manufactured ones first. Children can change the type and amount of sand and/or the size of the hole. Let them explore this without your support. Making the timers will be easier if children work in pairs. Children can use clocks to test their timer. If they find this difficult, let them compare their timer with a manufactured timer. Take it further The earliest records of sand timers date from the 14th century and they were often used as timers in factories and on sailing vessels. Sand timers are also known as sandglasses or hourglasses. Today, sand timers are frequently found in kitchens and board games. TESTING TIMERS It required great skill to create very accurate sand timers with the beautiful hourglass shape and a tiny hole to control the flow of the sand. Keywords • Time • Measuring TIMERS Watch out! Sand on the floor can be very slippery. Remind children not to rub their eyes when they are handling the sand and to wash their hands afterwards. Adult supervision may be required to make the holes in the cups. Make the hole from the inside of the cup. Use a soft surface underneath the cup. Find out more (links to further info) Egg timers normally run for three minutes. One minute timers are available via school suppliers see www. britishscienceassociation.org/creststar British Science Association Registered Charity No. 212479 and SC039236